A 3ILVICAL STUDY OF CERTAIN FACTORS
CONTRIBUTING TO THE DIFFERENTIAL HEIGHT GROWTH OF
PLANTATION-GROWN TULIP POPLAR
(LIRIODENDRON TULIP IF ERA L .)

By
R o bert Dean Shipman

A THESIS
S u b m itte d to th e School o f G radu ate S tu d i e s o f M ichigan
S t a t e C o lle g e o f A g r i c u l t u r e and A p p lie d S cien ce
i n p a r t i a l f u l f i l l m e n t o f th e r e q u ire m e n ts
f o r th e d e g re e o f
DOCTOR OF PHILOSOPHY
DEPARTMENT OF FORESTRY

1952

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AOKNOVILEDGrMSKDS

The a u th o r i s in d e b te d t o many p e r s o n s f o r a s s i s t a n c e , a d v i c e , and
s u g g e s t i o n s i n t h e a n a l y s i s o f r e s e a r c h upon w hich t h i s d i s s e r t a t i o n i s
b a s e d and i n t h e c o l l e c t i o n o f f i e l d d a t a .

P a r t i c u l a r acknowledgment i s

g iv e n to t h e f o l l o w i n g members of th e f a c u l t y of M ichigan S t a t e C o lle g e ,
who th r o u g h t h e i r e n co u ragem ent, i n t e r e s t , and p r o v i s i o n o f a s s i s t a n c e
f a c i l i t a t e d th e e x e c u tio n o f th e r e s e a r c h ;

D r. T e r r i l l D. S te v e n s ,

whose a d m i n i s t r a t i v e h e l p c o n t r i b u t e d to th e c o l l e c t i o n and assem bly o f
f i e l d d a ta ;

D r. Eugene P . W h ite s id e , who a id e d in mapping t h e s o i l s of

th e e x p e r im e n t a l a r e a .

D r. K irk Lawton, who gave in v a l u a b l e a d v ic e on

c e r t a i n c h e m ic a l d e t e r m i n a t i o n s o f th e s o i l s ;

D r. Lloyd M. Turk, whose

c r i t i c i s m o f th e m i c r o b i o l o g i c a l s t u d i e s was i n e s t i m a b l e ;

D r. S ta n a r d G.

B e r g q u i s t and D r. W illia m B. Drew, whose s u g g e s tio n s and a d v ic e on th e
g e o lo gy and b o ta n y o f t h e a r e a r e s p e c t i v e l y , c o n t r i b u t e d to th e e c o lo g ­
i c a l p h a s e s o f th e s tu d y ;

D r. Edward D. D evereux, who p r o v id e d b a c t e r i a l

media f o r t h e m i c r o b i a l d e t e r m i n a t i o n s ; and Dr. W illiam D* B a te n , who
a d v is e d upon th e s t a t i s t i c a l a n a l y s i s of th e d a t a .
The w r i t e r d e e p ly a p p r e c i a t e s th e f i n a n c i a l s u p p o rt o f f e r e d th ro u g h
th e Alumni P r e - B o c t o r a l F e llo w s h ip , School of G raduate S t u d i e s , M ichigan
S t a t e C o lle g e .
The i n v e s t i g a t o r e x te n d s h i s s i n c e r e th a n k s to Mr. C. I n g e r s o l l
A rn o ld , F o r e s t e r - i n - C h a r g e , Russ E x p e rim e n ta l F o r e s t , f o r h i s a s s i s t a n c e
and p e r m i s s i o n to u se m a t e r i a l s and equipment on th e Russ F o r e s t , Cass
C ounty, M ich ig an .

To my w i f e , L o u e l l a Shipman, who c o n t r i b u t e d t o th e t y p in g of
c e r t a i n p h a s e s o f t h e m a n u s c r ip t , g r a t e f u l acknowledgment i s g iv e n
fo r her p a tie n t effo rt*
The a u t h o r w is h e s t o e x p r e s s h i s s i n c e r e th a n k s to a layman,
Mr* L o u is R. P o t t s , S u p e r in t e n d e n t o f S c h o o ls , M a r s h a ll County,
West V i r g i n i a , u n d e r whose c o n tin u e d en cou ragem en t, i n s p i r a t i o n , and
u n f a i l i n g i n t e r e s t t h i s i n v e s t i g a t i o n was c o m p le te d .

R o b e rt Dean Shipman
c a n d i d a t e f o r th e d e g re e o f
D o c to r o f P h ilo s o p h y

P i n a l e x a m in a tio n :

D isse rta tio n :

O c to b er 2 2, 195^* 2:00 P . M,

Room 11, F o r e s t r y B u ild in g

A S i l v i c a l Study o f C e r t a i n F a c t o r s C o n t r i b u t i n g to th e
D i f f e r e n t i a l H e ig h t Growth o f P la n ta tio n - G r o w n T u lip
P o p l a r ( L ir io d e n d r o n t u l i p i f e r a L .)

O u tlin e of S tu d ie s :
M ajor s u b j e c t : F o r e s t r y
Minor s u b j e c t s : S o i l S c ie n c e , B otany
B i o g r a p h i c a l Ite m s :
B o rn , May 12, 1921, M o u n d s v ille , West V i r g i n i a
U n d e rg ra d u a te S t u d i e s , S y rac u se U n i v e r s i t y , 1939“ ^2 ,
U n i v e r s i t y o f M ichigan,
G ra d u a te S t u d i e s , U n i v e r s i t y of M ichigan, 19*+7-^9*
M ichigan S t a t e C o lle g e , 1950-52
E x p e r ie n c e :

Member;

F o r e s t S o i l s R e se a rc h A s s i s t a n t , C h ild s -W o lc o tt F o r e s t , 19^-2;
Member U n ite d S t a t e s Army A ir F o r c e , 19^2-A-6; P a rk F o r e s t e r ,
West V i r g i n i a , 19^7? A g r i c u l t u r a l A id e , U .S. F o r e s t S e r v i c e ,
19^9; F o r e s t R e s e a rc h Ass i s t a n t , M ichigan S t a t e C o lle g e , 1950;
G ra d u a te A s s i s t a n t , M ichigan S t a t e C o lle g e , 1950-5^1 G ra d u ate
F e llo w , M ichigan S t a t e C o lle g e , 1951-52

Xi Sigma P i , R a t i o n a l F o r e s t r y H onorary; P h i E p s ilo n P h i ,
R a t i o n a l B o t a n i c a l H on o rary ; S o c ie ty of American F o r e s t e r s ;
A merican F o r e s t r y A s s o c i a t i o n ; S o i l S c ie n ce S o c ie ty o f America

A SILVICAX STUDY 05* CERTAIN FACTORS CONTRIBUTING TO THE DIFFERENTIAL HEIGHT
GROWTH OF PLANTATION-GROWN TULIP POPLAR ( LIRIODENDRON TULIPIFERA L«)

By
R obert Bean Shipman

AN ABSTRACT
S ubm itted to th e School o f G raduate S tu d ie s o f M ichigan
S ta te C o lleg e o f A g r ic u ltu r e and A p p lied Science
in p a r t i a l f u l f i l l m e n t o f th e re q u ire m e n ts
f o r th e degree of

DOCTOR OF PHILOSOPHY

D epartm ent o f F o r e s tr y

Approved

ABSTRACT
A com prehensive s i l v i c a l s tu d y o f p la n ta tio n -g ro w n t u l i p p o p la r
(L irio d o n d ro n t u l i p i f e r a L*) was conducted a t th e F red S uss E x p erim en tal
F o r e s t i n Cass C ounty, M ichigan, d u rin g th e grow ing seasons 1951-52.
T h is i n v e s t i g a t i o n In c lu d e d th e r e s u l t s o f b o th f i e l d and la b o r a to r y
s tu d ie s i n an e f f o r t to d eterm in e th e s i l v i c a l req u ire m e n ts o f p l a n t a t i o n grown t u l i p p o p lar*

A knowledge o f th e grow th h a b its o f t h i s s p e c ie s

under th e c lim a tic c o n d itio n s o f so u th w estern M ichigan seemed a d v isa b le *
In th e v i c i n i t y o f th e ex p e rim e n ta l a r e a th e re i s a la r g e number o f
fa rm e rs and p r i v a t e la n d owners who a r e i n t e r e s t e d i n c o n v e rtin g abandoned
farm la n d in to t r e e farm s

a s a c o n tin u e d investm ent*

S ince t u l i p p o p la r

i s a d e s ir a b le s p e c ie s from th e s ta n d p o in t o f econom ical r e f o r e s t a t i o n ,
th e p r e s e n t stu d y was I n i t i a t e d to determ ine th e f e a s i b i l i t y o f recom­
mending t u l i p p o p la r p la n tin g s f o r such e n te r p r is e s *
The r e s e a r c h work was c a r r i e d o u t on a 15 y e a r o ld -2 0 a c re t u l i p
p o p la r - c a ta lp a p la n ta tio n *

O b serv atio n o f th e t u l i p t r e e s i n t h i s

p a r t i c u l a r p l a n t a t i o n r e v e a l a marked d i f f e r e n t i a l r a t e o f h e ig h t grow th
on t r e e s o f th e same age and d e n sity *

T his d if f e r e n c e i n h e ig h t grow th

i s a s s o c ia te d w ith th e p re se n c e o f an o ld -g ro w th hardwood s ta n d a d jo in in g
th e p l a n t a t i o n on th e so u th and west*

The e x p e rim e n ta l a r e a was a r b i ­

t r a r i l y d iv id e d i n t o two d i s t i n c t s i t e s (A rea X and A rea Y) f o r r e s e a r c h
p u rp o s e s .

E daphlc ( p h y s ic a l and c h e m ic a l), m icro c li m a tic , and q u a n t ita t iv e

s o i l m ic ro b io lo g ic a l d a ta were o b ta in e d a t th e same sam pling p l o t s i n b o th
a re a s*

The app ro ach to th e problem was to d eterm in e what f a c t o r o r s e t o f

f a c t o r s were c o n tr ib u tin g to th e marked d i f f e r e n t i a l h e ig h t grow th o f
p la n ta tio n -g ro w n t u l i p p o p la r .

2

L a b o ra to ry e x p erim e n ts on th e p h y s ic a l-e d a p h ic f a c t o r s o f th e two
compared s i t e s , r e v e a le d o n ly two p r o p e r t i e s o f an a c tu a l and s t a t i s t i c a l l y
s i g n i f i c a n t d iff e r e n c e *

These two r e l a t e d f a c t o r s , th e amount o f f in e

c la y and th e w a te r-h o ld in g c a p a c ity , were th e o n ly p h y s ic a l-e d a p h ic f a c t o r s
w h ic h

d i f f e r e d s i g n i f i c a n t l y betw een A rea

X

and A rea T.

Ten p h y s ic a l-

e d ap h ic p r o p e r t i e s were s tu d ie d i n d e t a i l and t r e a t e d s t a t i s t i c a l l y by
a n a l y s i s o f v a ria n c e *

The p h y s ic a l s o i l f a c t o r s in v e s tig a te d i n r e l a t i o n

to h e ig h t grow th were s o i l t e x t u r e , s p e c i f i c g r a v i ty , volume w e ig h t,
p o r o s i t y , h y g ro sc o p ic c o e f f i c i e n t , w a te r-h o ld in g c a p a c ity , m o istu re
e q u iv a le n t, s o i l e v a p o ra tio n l o s s , depth o f l a t e r a l r o o t p e n e t r a tio n ,
and th e w a te r t a b l e f lu c tu a tio n *
A s t a t i s t i c a l tre a tm e n t o f seven im p o rta n t ch em ical-ed ap h ic f a c t o r s
in each a r e a in d ic a te d no o u ts ta n d in g a c t u a l o r s t a t i s t i c a l l y s i g n i f i c a n t
d i f f e r e n c e betw een th e a r e a s o f good and p oor h e ig h t grow th o f t u l i p
p o p la r*

F u r th e r v e r i f i c a t i o n of th e la c k o f an y chem ical s o i l d if f e r e n c e

was s u b s t a n t i a t e d by a stu d y o f seven in d iv id u a l m ajor n u t r i e n t elem ents*
A grow ing seaso n stu d y o f Beven m lc ro c lim a tic f a c t o r s in r e l a t i o n to
s o i l f a c t o r s o f b o th a r e a s in d ic a te d in v i r t u a l l y e v ery case t h a t th e
i n t e g r a te d elem en ts o f e v a p o ra tio n , r e l a t i v e h u m id ity , a i r te m p e ra tu re ,
s u rfa c e s o i l te m p e ra tu re , p e r c e n t a v a ila b le m o is tu re , and l i g h t i n t e n s i t y ,
were c lo s e ly r e l a t e d to th e marked d i f f e r e n t i a l h e i ^ i t grow th o f t u l i p
p o p l a r , i n s o f a r a s th e s e f a c t o r s c o n d itio n e d th e s o il- m o is tu r e regimen*
S upplem ental s tu d ie s on grow th r a t e s , sun s c a ld , b a rk th ic k n e s s , h erbaceous
p l a n t s u c c e s s io n , and s o i l m ic ro b io lo g ic a l co u n ts f u r t h e r s u b s ta n tia te d
th e e f f e c t o f m ic ro c lim a te on s o l 1 -m o istu re requirem ents*
The co n tin u o u s s o il- m o is tu r e regim en th ro u g h o u t th e grow ing season

R obert D. Shipman

3

was found to be th e p r i n c i p a l l i m i t in g f a c t o r c o n tr ib u tin g to th e marked
d i f f e r e n t i a l h e i g h t grow th o f p la n ta tio n -g ro w n t u l i p p o p lar*

R obert D. Shipman

COHTENTS
Page
Acknowledgments
X.
II.
III.
IV.
V.
V I.

V II.
V III.
IX.

X.
X I.

S ta te m e n t o f th e P roblem

1

Review o f L i t e r a t u r e

7

H i s t o r y o f Russ F o r e s t and D e s c r i p t i o n o f E x p e rim e n ta l A rea

19

Scope o f E x p e rim e n ta l Work

144

S o i l Sam pling T echnique and S t a t i s t i c a l A n a ly s is o f D ata

*+7

L a b o r a t o r y E x p erim en ts (Phys i c a l - E d a p h ic )

51

A.

Summary and I m p l i c a t i o n o f R e s u l t s

B.

Root P e n e t r a t i o n in R e l a t i o n to Edaphic F a c t o r s

101

C.

W a te r-T a b le F l u c t u a t i o n and P h y s ic a l - E d a p h ic F a c t o r s

107

96

L a b o r a to r y E xp erim ents ( C hem ical-E daphic)

110

Summary and I m p l i c a t i o n of C hem ical-E daphic F a c t o r s

1^3

F i e l d - P l a n t a t i o n E x p erim ents

151

A.

Growth R ate of T u lip P o p l a r

151

B.

P r e c i p i t a t i o n and Tem perature in R e l a t i o n to Growth

l6H

C.

R a d i a l Growth in A d jo in in g Hardwoods

17S

D.

S u n s c a ld i n R e l a t i o n to H e ig h t Growth

181

E.

H erb aceo us V e g e ta tio n in R e l a t i o n to S o i l M o is tu r e

187

F.

M i c r o c l i m a t i c F a c t o r s and H e ig ht Growth

198

S o i l M i c r o b i o l o g i c a l E x p erim en ts

212

Summary and C o n c lu sio n s

2^0

L i t e r a t u r e C ite d

2^6

A SILVICAL STUDY OF CERTAIN FACTORS
CONTRIBUTING TO THE DIFFERENTIAL HEIGHT GROWTH
OF PLANTATION-GROWN TULIP POPLAR (LIRIODENDRON TULIPIFERA L .)

By
R o b e rt Dean Shipman

STATEMENT OF THE PROBLEM
T u l i p P o p l a r ( L i r io dend r on t u l i p i f e r a L .)

i s one o f th e most

v a l u a b l e hardwood t r e e s from th e s t a n d p o i n t o f th e f o r e s t e r .

A c co rdin g

to Harlow ( 1 9 ^ 1 ) , t h i s s p e c i e s may r e a c h a maximum h e i g h t o f tw o-h u nd red
f e e t w i t h a maximum d ia m e te r o f tw e lv e f e e t .

The a v e r a g e - s i z e d o ld

g ro w th t r e e i s a p p ro x im a te ly o n e -h u n d re d f e e t t a l l and f o u r to s i x f e e t
in d i a m e t e r .

The b o l e i s s t r a i g h t , t a l l ,

c l e a r o f s i d e b ra n c h e s f o r a

c o n s i d e r a b l e d i s t a n c e above gro u nd l e v e l , and i n f o r e s t s ta n d s i t s u p p o r ts
a r a t h e r n a rro w , open crown.

I t s r o o t system i s u s u a l l y deep and w ide-

s p r e a d in g and b e s t g row th i s o b t a i n e d on m o is t b u t w e l l - d r a i n e d s o i l s of
lo o s e t e x t u r e and o f m oderate d e p th .

I n o ld f o r e s t s ta n d s i t i s n e v e r

v e ry a b u n d an t and o c c u r s u s u a l l y in m ix tu r e w ith o t h e r hardw oods.

In

M ich ig an , i t i s o f t e n a s s o c i a t e d w i t h b e e c h , m aple, basswood, b l a c k
c h e r r y , and th e o a k s .

Some s e e d i s p ro d u ced a n n u a l l y and th e minimum

com m ercial se e d b e a r i n g age o f t h i s s p e c i e s i s f i f t e e n to tw e n ty y e a r s ;
th e a v e r a g e g e r m in a tiv e c a p a c i t y is low (a b o u t 10 to 12 p e r c e n t ) .

1.

S u b m itte d in p a r t i a l f u l f i l l m e n t of th e re q u ire m e n t f o r th e
d e g re e o f D o c to r of P h ilo s o p h y to th e School of G ra d u a te S t u d i e s ,
M ichigan S t a t e C o lle g e o f A g r i c u l t u r e and. A p p lie d S c ie n c e .

2.

Names and d a t e s r e f e r to " L i t e r a t u r e C i t e d . "

2

A n o th e r s i l v i c a l c h a r a c t e r i s t i c o f t h i s s p e c i e s i s th e d e c id e d i n t o l e r ­
ance o f t h e t r e e , end o f t e n i t w i l l n o t compete s u c c e s s f u l l y even w i t h
th e o a k s .

N a t u r a l s e e d l i n g s o c c u r most f r e q u e n t l y in abandoned f i e l d s

o r o t h e r p l a c e s where a m in e r a l seed bed i s a v a i l a b l e and com peting
v e g e ta tio n sp arse .

S in c e t h i s s p e c i e s i s h i g h l y d e s i r a b l e a s a f o r e s t

t r e e , w i t h i t s f a i r l y r a p i d grow th and o t h e r d e s i r a b l e s i l v i c a l c h a r a c ­
t e r i s t i c s , a t t e m p t s a r e b e in g made to grow and p l a n t l a r g e numbers o f
se e d lin g s.

B ecause o f i t s u t i l i t y f o r numerous wood p r o d u c t s , i t s low

s u s c e p t i b i l i t y to s e r i o u s d i s e a s e s and i n s e c t s , t h i s s p e c i e s w i l l c o n tin u e
to be a p o p u l a r one in r e f o r e s t a t i o n and p l a n t a t i o n e n t e r p r i s e s .
I n s o u t h e r n M ich ig an , w hich r e p r e s e n t s t h e n o rth e rn m o s t l i m i t o f
i t s r a n g e i n t h i s s t a t e , t u l i p p o p l a r has be en p l a n t e d i n s e v e r a l e x per­
im e n ta l f o r e s t s u n d e r v a r i e d s p a c in g c o n d i t i o n s and in b o t h p u r e and
mixed p l a n t a t i o n s .

One such e x p e r im e n t a l t u l i p p o p l a r p l a n t a t i o n i s

l o c a t e d a t th e Russ E x p e rim e n ta l F o r e s t in V o l i n i a Township, Cass County,
M ic h ig a n .

The d i s s e r t a t i o n h e r e p r e s e n t e d d e a l s s p e c i f i c a l l y w i t h a

15 y e a r o ld - 2 0 a c r e t u l i p p o p l a r - c a t a l p a . p l a n t a t i o n on t h e Russ F o r e s t .
T h is p l a n t a t i o n was e s t a b l i s h e d in o r d e r to o b s e rv e t h e g ro w th and
s i l v i c a l r e q u ir e m e n ts o f t h i s s p e c i e s u n d e r th e e n v iro n m e n ta l c o n d i t i o n s
o f s o u th w e s te r n M ich ig an ,

I t i s a w e ll known f a c t t h a t many o f th e

abandoned a g r i c u l t u r a l s o i l s in t h i s a r e a a r e r e l a t i v e l y p o o r i n n u t r i ­
e n t s and so low in c o l l o i d s and o r g a n ic m a t t e r t h a t th e y p o s s e s s unde­
s i r a b l e p h y s i c a l and c h em ica l q u a l i t i e s f o r a g r i c u l t u r a l u s e .

T u l ip

p o p l a r t r e e s were p l a n t e d on t h e s e abandoned la n d s in o r d e r to o b s e rv e
t h e m ag n itu d e of t h e s e a p p a r e n t d e f i c i e n c i e s w ith r e s p e c t to t r e e s , and
to s tu d y th e re s p o n s e o f t u l i p p o p l a r to f a c t o r s o t h e r t h a n s o i l .

3

The f o l l o w i n g e c o l o g i c a l s tu d y on t u l i p p o p l a r has be en p ro p o s e d and
c a r r i e d o u t in c o n j u n c t i o n w i t h and s u p p le m e n ta l to a r e s e a r c h s tu d y begun
by t h e M ichigan A g r i c u l t u r a l Experim ent S t a t i o n u n d e r d i r e c t i o n of th e
F o r e s t r y D epartm ent o f M ichigan S t a t e C o lle g e .

As o r i g i n a l l y s e t u p , t h i s

r e s e a r c h p r o j e c t was e s t a b l i s h e d to s tu d y o n ly t h e m i c r o c l i m a t i c and
e d a p h ic f a c t o r s a f f e c t i n g th e r e s p o n s e end groiwth o f t u l i p poplar* on a
15 y e a r o l d - 20 a c r e p l a n t a t i o n .

A l l d a t a c o n ce rn e d w ith t h e two above

m e n tio n e d f a c t o r s a r e t h e p r o p e r t y o f A g r i c u l t u r a l E xperim ent S t a t i o n
r e c o r d s and a r e to be u se d in t h i s d i s s e r t a t i o n as s u p p o r t i n g c r i t e r i a
o n ly .

S p e c if ic a l ly , th e se f i e l d d a ta r e f e r to seasonal reco rd s o f s o i l

m o i s t u r e , r a t e o f e v a p o r a t i o n , r e l a t i v e h u m id ity , s o i l t e m p e r a t u r e , and
a i r te m p e ra tu re .

A l l o t h e r d a t a o f an edaphic., c l i m a t i c , o r b i o l o g i c a l

n a .tu re , a s w e ll as i t s i n t e r p r e t a t i o n and a n a l y s i s , a r e t h e p r o p e r t y of
th e i n v e s t i g a t o r .

H e e d le s s to s a y , i n an e c o l o g i c a l s tu d y o f th e ty p e

h e r e p r e s e n t e d , a l l f a c t o r s must be i n t e g r a t e d and w e ig h te d as t o t h e i r
e c o l o g i c a l and s t a t i s t i c a l s i g n i f i c a n c e .
H e igh t G-rowth D i f f e r e n t i a l
I t h a s be en o b s e rv e d t h a t t r e e s of t u l i p p o p l a r in t h i s p a r t i c u l a r
p l a n t a t i o n show marked d i f f e r e n t i a l r a t e s o f h e i g h t g ro w th on t r e e s o f
s i m i l a r ag e and d e n s i t y ( F i g s . 1 and 2 ) .

An a tte m p t is h e re b y made to

a s c e r t a i n th e e x t e n t o f th e c au se o r c a u s e s f o r t h i s marked v a r i a t i o n in
h e i g h t g ro w th .

I t i s th e c o n t e n t i o n of th e a u th o r t h a t i f t h e s e v a r i ­

a b l e s can be i s o l a t e d and p ro v e n s i g n i f i c a n t from an e c o l o g i c a l end
s i l v i c a l v ie w p o in t, th e n t h e s e f i n d i n g s may become a p p l i c a b l e to f u t u r e
p l a n t a t i o n s of t u l i p p o u l a r on t h i s and r e l a t e d a r e a s .

The answer would

k

F i g . 1.
A view showing t h e marked d i f f e r e n t i a l h e i g h t grow th o f
t u l i p p o p la r.
I n t h e fo r e g r o u n d , th e d im in u ti o n i n h e i g h t
g row th can he o b s e rv e d . I n th e b ack g ro u n d , s o u th o f th e p l a n ­
t a t i o n p r o p e r , i s Woods HB " , an o ld grow th mixed-hardwood f o r e s t .
T re e s a d j a c e n t to th e woods a r e !§■ - 2 tim e s th e h e i g h t o f th e
t r e e s n o r t h o f th e woods in th e same p l a n t a t i o n . Note th e b a s a l
s p r o u t i n g o f t u l i p t r e e s in th e immediate f o r e g r o u n d .

F ig . 2.
T h is view o f th e e x p e r im e n ta l p l a n t a t i o n shows th e g r a d a t i o n
in h e i g h t g row th p r o c e e d in g from th e o ld g ro w th woods i n t h e back­
g ro u n d t o t h e t u l i p t r e e s i n t h e f o r e g r o u n d . Note t h e t u l i p t r e e s
in immediate fo r e g r o u n d which were "drowned o u t" a s a r e s u l t o f
e x ce ssiv e s o i l m o istu re .

6

m a t e r i a l l y a i d t h e f a r m e r in t h i s r e g i o n and p r o v i d e a sound in v e stm e n t
f o r c o n v e r t i n g abandoned l a n d to f o r e s t p l a n t a t i o n s in s o u th w e s te r n
M ic h ig a n ,
I n o r d e r to expand and s tu d y t h i s problem more c o m p re h e n s iv e ly ,
a n o t h e r p h a s e o f th e o v e r a l l a n a l y s i s was added,

With th e c o n s e n t o f th e

F o r e s t r y D epartm ent o f M ichigan S t a t e G o lie g e , i t was deemed a d v i s a b l e to
c a r r y o u t a s tu d y to i n v e s t i g a t e some o f th e s o i l b i o l o g i c a l f a c t o r s t h a t
m igh t be in v o lv e d in th e d i f f e r e n t i a l h e i g h t g ro w th .

T his p h a s e o f th e

s tu d y w i l l a tte m p t t o d e te rm in e i f any d i r e c t c o r r e l a t i o n e x i s t s betw een
th e numbers o f organism s in th e s o i l and th e o t h e r f a c t o r s b e in g s t u d i e d
by th e F o r e s t r y D e p artm en t.

No a tte m p t w i l l be made to a s c e r t a i n a l l of

t h e b i o l o g i c a l i n t e r p r e t a t i o n s as r e l a t e d to th e d i f f e r e n c e in h e i g h t
g ro w th .

The m i c r o b i a l p h a se o f th e s tu d y w i l l r e s t r i c t i t s e l f to th e

i n v e s t i g a t i o n o f th e q u a n t i t a t i v e m i c r o f l o r a o f th e sam pling a r e a s .

T h is

p o r t i o n o f t h e d i s s e r t a t i o n w i l l a tte m p t to p l a c e m i c r o b i o l o g i c a l s t u d i e s
i n su ch a p e r s p e c t i v e as to d e m o n s tra te th e e c o lo g y o f th e s o i l o rg a n ism p l a n t community a s r e l a t e d t o th e f o r e s t e r ' s c o n c e p t o f s i t e q u a l i t y .
r e s u l t s o f t h i s i n v e s t i g a t i o n from i t s i n c e p t i o n in May 1951
1952 form th e b a s i s f o r t h i s s t u d y .

The

Septem ber

7

REVIEW OP LITERATURE

That toil ip p o p l a r ( L i r io d e n d ro n t u l i p i f e r a L .)

is a r a th e r c r i t i c a l

and. e x a c t i n g s p e c i e s w ith r e g a r d to i t s s i t e r e q u ir e m e n ts h a s been
d e m o n s tr a te d by v i r t u a l l y a l l r e s e a r c h w ork ers s tu d y in g th e s i l v i c a l
re q u ir e m e n ts o f t h i s s p e c i e s .

T u l i p p o p l a r h a s been l i s t e d by numerous

w r i t e r s a s b e i n g an i n t o l e r a n t t r e e , p r i m a r i l y w ith r e s p e c t to i t s l i g h t
re q u ire m e n ts.

More r e c e n t r e s e a r c h by th e p r e s e n t i n v e s t i g a t o r and

o t h e r s shows t h a t t u l i p p o p l a r must be c o n s id e r e d i n t o l e r a n t w i t h c e r t a i n
q u a lific a tio n s.

S p e c i f i c a l l y , t h i s s p e c i e s v a r i e s in i t s d e g re e of

i n t o l e r a n c e th r o u g h o u t i t s p h y s i o l o g i c a l g ro w th and de v elo p m en t.

For

exam ple, young t u l i p p o p l a r must have a c e r t a i n amount o f l i g h t in
e a r l y l i f e , b u t n o t to o much, and in more m ature days a l l th e l i g h t i t
can g e t .

Thus, i n d i s c u s s i n g th e s i l v i c a l re q u ir e m e n ts o f t h i s s p e c i e s

w i t h s p e c i a l r e f e r e n c e to p l a n t a t i o n g ro w th and s u r v i v a l , i t would a p p e a r
t h a t th e f o r e s t e r w ould p r o f i t by u n d e r s ta n d in g i t s r e q u ir e m e n ts a t
v a r i o u s s t a g e s o f c o n tin u in g grow th r a t h e r th a n a t a f i x e d s t a g e of
m a tu rity .
L i t e r a t u r e p e r t a i n i n g to t h e s p e c i f i c ty p e of d i s s e r t a t i o n h e r e
p r e s e n t e d i s n o t v o lu m in o u s.

F o r t h i s r e a s o n , t h e i n v e s t i g a t o r h as

sou g ht t o f i n d and r e v ie w in f o r m a t io n which b e a r s p r i n e i p a J . l v upon
p e r i p h e r y s t u d i e s r e l a t e d to th e p r e s e n t t h e s i s .

Those s t u d i e s c l o s e l y

r e l a t e d to t h i s i n v e s t i g a t i o n a r e p r e s e n t e d f i r s t and s u p p le m e n ta l s t u d i e s
fo llo w .
C ra ib (1929) made e x h a u s tiv e a n a l y s e s o f s o i l m o is tu r e in th e open
and i n th e f o r e s t a t Keene, New H am pshire.

He fo u n d t h a t in d ry p e r i o d s

s

th e s o i l s i n open s i t u a t i o n s c o n t a i n c o n s i d e r a b l y more m o is tu r e th a n th e
f o r e s t s o i l s , "based upon e i t h e r volume o r w eig ht d e t e r m in a tio n s *

T his

means t h a t th e l o s s o f w a te r th ro u g h th e combined a c t i o n of t r a n s p i r a t i o n
and e v a p o r a t i o n in t h e f o r e s t exceeds t h a t in th e open.

F orest s o ils

were fou n d to become p r o g r e s s i v e l y d r i e r w ith i n c r e a s e in d e p th , d e s p i t e
th e f a c t t h a t th e t r e e r o o t s were c o n c e n t r a t e d l a r g e l y i n th e s u r f a c e
la y e r s *

I n th e o pen, d u r in g v e r y d ry p e r i o d s , more m o is tu r e i s fo un d i n

th e s ec o n d 10 c e n t i m e t e r s o f s o i l t h a n in th e f i r s t .

T his i s due to th e

d r y in g e f f e c t o f th e e x p o su re o f th e f i r s t l a y e r t o sun and x^rind.

He

fo u n d th e m o i s t u r e c o n t e n t o f th e s u r f a c e l a y e r in th e two a r e a s te n d e d
to b e e q u a l .

I n t h i s l a y e r th e h ig h l o s s o f m o is tu r e by t r a n s p i r a t i o n

i n t h e f o r e s t te n d s to be e q u a l i z e d by an e q u a l l y h ig h l o s s o f m o is tu r e
by e v a p o r a t i o n in th e open.

His work i s c o r r e l a t e d w ith th e t r e n c h i n g

e x p e r im e n ts o f Tourney ( 1 9 2 9 ) .
S te w a r t (1933) c o n d u c te d a s tu d y to g iv e a p i c t u r e o f th e m ajor
p h y s i c a l , c h e m ic a l, and b a c t e r i o l o g i c a l d i f f e r e n c e s betx^een th e v a r i o u s
g ro u p s o f f o r e s t and p a s t u r e a s s o c i a t i o n s .

He s t u d i e d s o i l p r o f i l e s in

t h e f i e l d , d e te r m in e d p e r m e a b i l i t y o f s o i l s in th e f i e l d , and c o n d u cte d
o t h e r p h y s i c a l and c h e m ic a l s o i l i n v e s t i g a t i o n s .

The b a c t e r i o l o g i c a l

work c o n s i s t e d o f t h e d e t e r m i n a t i o n o f t h e amounts o f

and

formed

a f t e r s t o r a g e , c o u n ts on A z o to b a c te r and th e p r e s e n c e o r a b se n c e o f
legume o rg a n is m s .
A u te n (19^5) c o n d u c te d a s t u d y on 77 n a t u r a l , s e c o n d -g ro w th y e llo w
p o p l a r s ta n d s v a r y in g i n age from 12 to 6 l y e a r s in T e n n e ss e e , K entucky,
O hio, I n d i a n a , and I l l i n o i s , f o r th e p u rp o s e o f s e t t i n g v a lu e s on s o i l
p r o p e r t i e s and to p o g r a p h ic f e a t u r e s as a g u id e i n p r e d i c t i n g s i t e q u a l i t y

9

f o r y e llo w p o p la r .

He e s t a b lis h e d the f a c t th a t th e depth o f in c o r p o r a tio n

o f o rg a n ic m atter in th e su r fa c e s o i l h o rizo n a ffo r d s a u s e fu l c r i t e r i o n o f
th e s i t e in d ex .

I f th e depth o f in c o r p o r a tio n (A^ h orizon ) i s l e s s than

one in c h , t u l i p poplar* does not show s a t i s f a c t o r y developm ent; average or
b e t t e r s i t e s f o r y e llo w p op lar occur where depth o f th e A-^ h o rizo n i s
th re e in ch es or more.

Auten found the depth to t ig h t s u b s o il was a b e tt e r

c r i t e r i o n o f s i t e in d ex f o r t u l i p p o p la r .

The p resen ce o f a t ig h t s u b s o il

l e s s than tw e n ty -fo u r in ch es below the s u r fa c e r e s u lt s in p oorer than
average s i t e s .

P o o r e st growth o f t u lip p op lar was observed on r id g e s and

exposed s i t e s .

W ithin the range o f s o i l s s tu d ie d , he found no c o r r e la tio n

betw een s i t e
of s o ils .

index and cs,lcium , magnesium, phosphorus, and potassium co n ten t

A lso s i t e index m s not r e la t e d to r e a c tio n (pH v a lu e) o f the

s o i l o f any h o r iz o n .
Prom 190S to 1919 P n g le r (1919) co n d u cted e x p e rim e n ts on s o i l d e n s i t y ,
p o re s p a c e , w a t e r - h o l d i n g c a p a c i t y , w a te r c o n t e n t , p e r m e a b i l i t y and evapo­
r a t i o n , c o r r e l a t i n g i n each c a s e t h e e f f e c t o f t h e f o r e s t on t h e f a c t o r in
q u e stio n .

A f t e r an e x h a u s tiv e e l e v e n - y e a r s tu d y , H ngler c o n c lu d e d t h a t

t h e combined l o s s o f w a te r from t r a n s p i r a t i o n and e v a p o r a t i o n from open
s o i l s ex ce e d s t h a t from f o r e s t s o i l s , t h u s mailing th e f o r e s t e x e r t a
b e n e f i c i a l i n f l u e n c e on th e w a te r re g im e n .

F o r t h i s r e a s o n he c o n c lu d e s

t h a t more m o is tu r e i s fo u n d in f o r e s t s o i l s d u r in g d r y p e r i o d s o f summer
th a n i s fo u n d in s i m i l a r open s o i l s .

These r e s u l t s were s i m i l a r to

s t u d i e s made by B u rg e r ( 1 9 2 3 ) w ith t h e e x c e p tio n t h a t B u rg e r fo u n d t h a t ,
d u r in g th e d r i e s t p e r i o d s o f th e summer months, t h e f o r e s t s o i l c o n s i s t e n t l y
m a in ta in e d a low er w a te r c o n te n t th a n s i m i l a r a g r i c u l t u r a l o r meadow s o i l s .
T h i s , he s t a t e s , i s due to th e h ig h r a t e o f w a te r l o s s th ro u g h t r a n s p i r a t i o n
by th e f o r e s t .

10

The work o f E ngler has been r e fu te d and c o n tr a d ic ts th e work o f v a rio u s
in v e s t ig a t o r s such as Ebermayer (1 8 8 9 ). Burger (1923)* and Halden ( 1926) .
These l a t t e r in v e s t ig a t o r s found th a t th e f o r e s t e d a rea s co n ta in ed co n sid ­
era b ly l e s s m oistu re than th e open areas during th e growing season*

Halden

(1926) a ls o found th a t both in the open and in th e f o r e s t th e su r fa c e la y e r
i s th e more m o is t, bu t during p e r io d s of drought t h is d is t r ib u t io n in th e
open may be r e v e r se d .
McCarthy (1933) p o in ts out th a t th e r e are many in d ic a tio n s in th e
ob served b eh avior o f younger t u l i p p op lar t r e e s , th a t in e a r ly youth the
s p e c ie s must have adequate l i g h t and m o istu re .

In a d d itio n to t h i s , t u lip

p o p la r must be fa v o r e d by c lim a te , both in p r o te c tio n from extrem es of
tem perature and a ssu ran ce o f a rea so n a b ly lo n g growing sea so n .

I n d ic a tio n s

of th e e f f e c t of c lim a te are found in in ju r y to th e th in bark o f young
tr e e s through sun s c a ld s , which have been noted by McCarthy in southern
In d ia n a .

In i t s extreme sou th ern range, y e llo w pop lar grows o n ly on m oist

s i t e s where i t is p r o te c te d from extrem e d ry in g .

McCarthy was unable to

determ ine to what d egree tem perature i s a fa c to r in grow th.
McCarthy p o i n t s o u t t h a t good g ro w th o f t u l i p p o p l a r on sandy s o i l s ,
a s on th e Cumberland P l a t e a u o f T e n n e s s e e , a p p e a rs to be s u i t a b l e o n ly i f
f r e e from e x c e s s i v e d r y i n g .

He s t a t e s t h a t t h r i f t y t r e e s a r e n e v e r fou nd

on v e ry d r y o r v e r y wet s o i l s ; t h e t r e e i s c h a r a c t e r i s e d by b e in g v e ry
e x a c t i n g in s o i l - m o i s t u r e r e q u i r e m e n t s .

He found t h a t th e i n f l u e n c e o f

c h em ica l c o m p o sitio n o f s o i l on th e g ro w th of p o p l a r i s a p p a r e n t l y s l i g h t ;
i t grew w e ll on s o i l s h ig h in lim e and on th o s e d e f i c i e n t in lim e .

McCarthy

o b s e r v e s t h a t d ry s i t e c o n d i t i o n s a r e r e f l e c t e d in a marked r e d u c t i o n o f
g row th r a t e and l o v e r d e n s i t y o f n a t u r a l s t a n d s .

On s te e p h i l l s i d e s y e llo w

11

p o p la r w ill
d ista n ce

o f t e n e x h i b i t a marked d i f f e r e n c e in h e i g h t g ro w th w i t h i n a

o f 50 f e e t up o r down t h e s l o p e .

He p o i n t s o u t t h a t marked d i f f e r e n c e s in h e i g h t and d ia m e te r grow th
may o c c u r on e ro d e d f i e l d s , w ith t r e e s o f th e same a g e .

The r a t e o f d i a ­

m e te r g ro w th o f y e llo w p o p l a r i s d e te rm in e d by th e s i z e o f t h e crown formed
and r e t a i n e d by t h e t r e e .

I f a g o o d ly p o r t i o n o f th e t o t a l h e i g h t i s

o c c u p ie d by t h e crown, th e t r e e w i l l grow r a p i d l y i n d ia m e te r , b u t t h e b o le
w i l l t a p e r v e r y s h a r p l y w i t h i n t h e crown.
S h i r l e y (1929) in d i s c u s s i n g t h e h e i g h t and d ia m e te r g ro w th o f t r e e s
sta te s,

nlow l i g h t i n t e n s i t i e s s t i m u l a t e h e i g h t g ro w th a t th e expense o f

d ia m e te r grovvrth, to p grow th a t t h e expense o f r o o t grovrth, l e a f a r e a dev­
elopm ent a t th e exp en se o f l e a f t h i c k n e s s , and s u c c u le n c e a t th e expense
o f s t r e n g t h and s t u r d i n e s s .
A c co rd in g t o T a y lo r (1917) t u l i p p o p l a r i s e x a c t i n g i n i t s s o i l ,
m o i s t u r e , and l i g h t r e q u i r e m e n t s .
y e t m o ist.

I t demands a s o i l t h a t i s w e ll d r a in e d

L ig h t san d s and heavy c l a y s a r e u n f a v o r a b le to i t s grow th.

T u l ip p o p l a r w i l l n o t t h r i v e in th e sh a d e ; i f o v e rto p p e d f o r a s h o r t
tim e by o t h e r t r e e s i t soon d i e s .

The c l e a n , smooth t r u n k i s e v id e n c e t h a t

i t c an n o t t o l e r a t e sh a d e .
Tourney and K o r s t i a n (1937) made th e o b s e r v a t i o n t h a t a v a i l a b l e w a te r
and e v a p o r a tio n work t o g e t h e r in c a u s in g d i f f e r e n c e s in gro w th form.
p ira tio n

i s a p h y s i o l o g i c a l p r o c e s s d e te rm in e d

f a c t o r s . The e x t e r n a l f a c t o r s a r e e v a p o r a tio n

T ran s­

by b o th e x t e r n a l and i n t e r n a l

which i n f l u e n c e s p a r t s above

g ro u n d , and a v a i l a b l e s o i l w a te r which in f l u e n c e s t h e p a r t s below g ro u n d .
E v a p o r a tio n th u s by a f f e c t i n g s o i l c o n d i t i o n s , a l s o i n f l u e n c e s t h e p a r t s o f
t r e e s below th e s u r f a c e .

12

A c o r r e l a t i o n a p p e a r s to e x i s t "between h e i g h t grow th o f t r e e s and a v a i l a b l e
w a te r s u p p ly .

A d e c r e a s e in th e w a te r r e q u ir e m e n ts f o r optimum g ro w th r e s u l t s

in a r a p i d f a l l i n g o f f in h e i g h t growth* e s p e c i a l l y d u r in g t h e grow ing s e a s o n .
T h in s o i l s i n which t h e r e i s a s c a n t y su p p ly o f m o is tu r e d u r in g th e growing
s e a s o n p ro d u c e t r e e s o f low h e i g h t f o r th e s p e c i e s ( C o i l e , 1 9 3 5 )-

Dry s o i l

and h i g h e v a p o r a t i o n c a u s e t r e e s to assume a c h a r a c t e r i s t i c s t u n t e d g ro w th .
H ic o ck , Morgan, L u tz , B u ll and L unt (1931) s t u d i e d th e r e l a t i o n s h i p be­
tween s o i l ty p e and v e g e t a t i o n on f o u r e x p e r im e n ta l t r a c t s , a g g r e g a t i n g 210
a c r e s in C o n n e c t i c u t .

Woody v e g e t a t i o n was c h a r t e d on t r a n s e c t s and t h e

h e rb a c e o u s v e g e t a t i o n s t u d i e d by means o f q u a d r a t s .

C o r r e l a t i o n o f a g iv e n

t r e e s p e c i e s w ith a s p e c i f i c s o i l ty p e was l a r g e l y u n s u c c e s s f u l .

By c l a s s ­

i f y i n g t h e s o i l s i n t o f o u r b ro a d g ro u p s on th e b a s i s o f m o is tu r e c o n d i t i o n s ,
some c o r r e l a t i o n was e v i d e n t .

T u l ip p o p l a r formed l e s s th a n one p e r c e n t o f th e

t o t a l and t h r e e p e r c e n t o f th e p r i n c i p a l s t a n d .

I t was found t o some e x t e n t

on a l l b u t th e d r i e s t s o i l s , b u t was most abundant on s o i l s h a v in g a h ig h
m o istu re c o n te n t.

P o p l a r was n o t fo u n d on muck, and i t seemed to show a

marked p r e f e r e n c e f o r t h e h e a v i e r w e l l - d r a i n e d s o i l s .
D a ta o b t a i n e d by t h e s e i n v e s t i g a t o r s i n d i c a t e t h a t th e s lo w ly d r a i n e d
s o i l s s u p p o r t a g r e a t e r number o f b o th s p e c i e s and i n d i v i d u a l s o f h e rb a c e o u s
and shru bb y p l a n t s th a n t h e r a p i d l y d r a i n e d s o i l s .

A tte m p ts were l a r g e l y

u n s u c c e s s f u l in u s in g p l a n t s a s i n d i c a t o r t y p e s , e x c e p t in b ro a d s o i l d i v i s ­
io n s b a se d upon s o i l - w a t e r r e l a t i o n s .

They found m eso ph ytic s p e c i e s on th e

slo w ly d r a i n e d loams and x e ro -m e s o p h y tic p l a n t s on th e more r a p i d l y d r a i n e d
and d r i e r s o i l s .

The g e n e r a l l a c k o f c o r r e l a t i o n betw een c e r t a i n p l a n t s and

s o i l ty p e s was p o s s i b l y due to th e f a c t t h a t th e g e n e r a l e x c e l l e n c e o f c l i m a t i c
f a c t o r s may com pensate to some e x t e n t f o r p o v e r ty of c e r t a i n s o i l c o n d i t i o n s .

13

T h is would "be p a r t i c u l a r l y t r u e w i t h i n r a t h e r n arrow l i m i t s o f s o i l v a r i a t i o n .
K ie n h o lz (19^-1) s t u d i e d th e s e a s o n a l c o u rs e o f h e i g h t g row th in c e r t a i n
hardwoods i n C o n n e c t i c u t ,

The s e a s o n a l c o u rs e o f h e i g h t g ro w th o f t r e e s ,

f i r s t y e a r s p r o u t s , and second y e a r s p r o u t s was m easured d u r in g f o u r grow­
in g s e a s o n s .

Most o f t h e s p e c i e s s t a r t e d h e i g h t gro w th l a t e in A p r i l o r

v e r y e a r l y May; t h e r e was a s u r p r i s i n g l y l i t t l e d i f f e r e n c e "between th e
d i f f e r e n t s p e c i e s examined in th e tim e o f s t a r t i n g g row th .

K ie n h o lz g ro up ed

t h e hardwoods i n t o two main c l a s s e s on t h e b a s i s o f t h e i r s e a s o n a l h e i g h t
gro w th b e h a v i o r .

The seco n d c l a s s i s r e p r e s e n t e d by g ra y and w h ite b i r c h ;

s c a t t e r e d m easurem ents i n d i c a t e d t h a t t u l i p p o p l a r has s i m i l a r g ro w th c u r v e s .
Growth f o r s p e c i e s a l l i e d to t u l i p p o p l a r s t a r t e d in l a t e A p r i l , r o s e
g r a d u a l l y t o a p e a k o f maximum grow th in m id -Ju n e , f e l l o f f g r a d u a l l y t o
c e a s e i n m id-A ugust — a grow ing s e a s o n o f 110 d a y s .

N in e ty p e r c e n t o f th e

h e i g h t g ro w th was co m p le ted in a bo ut 60 days from May 20 to J u l y 20.

The

s e a s o n a l p r o g r e s s o f g ro w th was g r a p h i c a l l y shown by p l o t t i n g a v e ra g e d a i l y
in c re m en t in m i l l i m e t e r s a g a i n s t w eekly p e r i o d s .

The curve o f g ro w th o f any

g i v e n s p e c i e s was q u i t e s i m i l a r from y e a r to y e a r , e s p e c i a l l y th e tim e o f
r e a c h in g th e p e ak o f most r a p i d g row th .
D i l l e r ( 1930 ) c o n d u cte d an i n v e s t i g a t i o n on t h e r e l a t i o n o f te m p e r a tu r e
and p r e c i p i t a t i o n to th e g row th o f b e ec h i n n o r t h e r n

In d ia n a .

He d e te rm in e d

t h e a v e ra g e a n n u a l r i n g w id th f o r t e n dominant b e ec h t r e e s in e ach o f sev en
beec h -m a p le woodlands f o r th e p e r i o d 1913-1933•

From h i s r e s u l t s , y e a r l y

v a r i a t i o n s in th e w id th o f a n n u al r i n g s f o r a 2 0 - y e a r p e r i o d were i n v e r s e l y
c o r r e l a t e d w ith th e a v e r a g e te m p e r a tu r e f o r th e month o f J u n e .

Y e a rly v a r ­

i a t i o n s i n th e w id th of th e a n n u a l r i n g s f o r t h e same p e r i o d were c o r r e l a t e d
d i r e c t l y in c e r t a i n woodlands w ith th e t o t a l p r e c i p i t a t i o n f o r th e month o f

Ik

J u n e a t s t a t i o n s n e a r e s t th e woodlands s t u d i e d .

D i l l e r fo u n d t h a t in most

c a s e s , d r o u g h t y e a r s showed t h e i r e f f e c t s on g ro w th t h e f o l l o w i n g y e a r
p r o b a b ly due t o an a cc u m u la te d d e f i c i e n c y in s o i l m o i s t u r e , w hereas wet
y e a r s showed an i n c r e a s e in g row th t h e same y e a r .

He s u rm is e s t h a t i f t h i s

p e r i o d o f d ro u g h t y e a r s c o n tin u e s o v e r an e x ten d e d p e r i o d t h e r e p r o b a b ly
would be a g r a d u a l r e t r o g r e s s i o n o f t h e b e ech-m ap le ty p e w ith t h e c o rre s p o n d ­
in g ad van ce o f th e oak-m aple and o a k - h ic k o r y f o r e s t t y p e s .
Bogue ( 1905 ) d e te r m in e d th e a v e ra g e w id th o f th e a n n u a l r i n g s o f k2
t r e e s n e a r L a n s in g , M ich ig an , f o r th e y e a r s 1%92 and 190^ and fo u n d a
c o r r e l a t i o n betw een p r e c i p i t a t i o n and w id th o f a n n u al r i n g s .

He s t a t e s t h a t

an a b n o rm a lly l a r g e o r sm a ll an n u al p r e c i p i t a t i o n i s e v id e n c e d by th e t r e e
g ro w th t h e f o l l o w i n g y e a r .
S te w a r t ( 1 9 1 3 ) compared th e w id th o f a n n u a l r i n g s o f an oak stump a t
York, Hew Y ork, w ith w e a th e r r e c o r d s a t R o c h e s te r , 25 m ile s n o r t h .

G reater

c o r re s p o n d e n c e was fo u n d betw een v a r i a t i o n s in r a i n f a l l f o r June and J u l y and
r i n g w id th t h a n betw een r a i n f a l l f o r th e e n t i r e grow ing s e a s o n and r i n g w id th .
P e a r s o n (1918) compared t h e a n n u al h e i g h t g row th o f P o n d e ro s a P in e
s a p l i n g s and th e p r e c i p i t a t i o n f o r v a r i o u s p e r i o d s .
p re c ip ita tio n

He fo u n d t h a t s p r i n g

( A p r i l and May) was a p p a r e n t l y th e c o n t r o l l i n g f a c t o r .

F a c to rs

r e f l e c t i n g th e a tm o s p h e r ic c o n d i t i o n s i n c lu d in g e v a p o r a tio n showed a c l o s e ,
tho u g h n o t c o n s i s t e n t , r e l a t i o n to h e i g h t gro w th .

The h e i g h t grow th v a r i e d

i n v e r s e l y w ith th e te m p e r a t u r e p ro b a b ly b e ca u se o f th e in f l u e n c e of tem per­
a t u r e on t r a n s p i r a t i o n and t h e r e f o r e on th e r e l a t i v e w a te r s u p p ly .
A r e c e n t s tu d y by Tryon and Myers (1952) shows t h a t p e r i o d i c p r e c i p i t a t i o n
th ro u g h o u t th e summer months (May 1 to June 3$) f o r a l o c a l i t y in West V i r g i n i a ,
was h i g h l y c o r r e l a t e d w ith w id th o f a n n u al r i n g f o r t u l i p p o p l a r .

Hine t u l i p

15

p o p l a r t r e e s i n th e co -d o m in a n t and dom inant c r o w n - e la s s e s were examined f o r
r a d i a l g ro w th by means o f in c re m en t c o r e s f o r t h e p e r i o d 1929 to 19 ^ 9 *

E e su lts

i n d i c a t e d a b e t t e r r e l a t i o n s h i p betw een r a d i a l g ro w th and p r e c i p i t a t i o n
d u r in g May 1 t o Ju n e 3^» t h e e a r l y p o r t i o n o f t h e grow ing s e a s o n , th a n f o r th e
p e r i o d most n e a r l y c o v e r in g th e e n t i r e grow ing s e a s o n , May 1 to August 31*
C o r r e l a t i o n c o e f f i c i e n t s f o r th e f i r s t p e r i o d was 0 .6 7 5 and t h a t o f t h e
l a t t e r 0 .5 5 9 -

Growth r i n g b o r in g s on t r e e s ta k e n on o t h e r s p e c i e s in th e

s t a n d showed no a p p a r e n t c o r r e l a t i o n w ith p r e c i p i t a t i o n , i n d i c a t i n g t h a t
t h e s e s p e c i e s a r e l e s s s e n s i t i v e to low s o i l m o is tu r e th a n t h e y e llo w p o p l a r .
M in c k le r (19^-1, 19^3) r e p o r t e d on f i r s t - y e a r s u r v i v a l o f t u l i p p o p l a r
on o l d - f i e l d p l a n t a t i o n s i n t h e G re at A p p a la c h ia n V a lle y .

S e e d lin g s o f 1-0

s t o c k o f t u l i p p o p l a r were p l a n t e d on o n e - f o u r t h a c r e e x p e r im e n ta l p l o t s ,
each p l o t c o n t a i n i n g 297 t r e e s .

A n a ly s is o f t h e d a t a was b a se d upon p e r ­

c e n ta g e s u r v i v a l p e r p l o t a t th e end o f t h e f i r s t grow ing s e a s o n .

Three s o i l

t y p e s , two s lo p e a s p e c t s and two grow ing s e a s o n s were u s e d a s c r i t e r i a f o r
su rv iv a l.

M in c k le r fo u n d t h a t in a v e r y d ry y e a r , t u l i p p o p l a r gave o n ly

f a i r s u r v i v a l on lim e s to n e s o u th s lo p e s and f a i l e d e n t i r e l y on s h a l e s o u th
slo p es.

White p i n e was much l e s s a b l e to t o l e r a t e heavy v e g e t a t i v e comp­

e t i t i o n t h a n was y e llo w p o p l a r .

M o r t a l i t y c aused by d ro u g h t was g r e a t e s t f o r

t u l i p p o p l a r on s h a l e and l im e s to n e s o u th s l o p e s .

When a l l s o i l t y p e - a s p e c t

c l a s s e s were c o n s i d e r e d t o g e t h e r , a s h and xiralnut c o n s t i t u t e d th e h i g h e s t
s u r v i v a l g ro u p , y e llo w 1 p o p l a r was sec o n d , and w h ite p i n e and s h o r t l e a f p in e
were t h i r d .

The im p o rtan c e o f th e c o n d i t i o n o f th e B s o i l h o r iz o n was

i l l u s t r a t e d by th e f o l l o w i n g com p arison s on v a r i o u s s i t e s .

On f r i a b l e ,

p l a s t i c , and s t i f f B h o r i z o n s , y e llo w p o p l a r mean h e i g h t g ro w th i n two y e a r s
was 2 . 5 , 1.5» a^d 0 .8 f e e t r e s p e c t i v e l y .

These r e s u l t s show t h e re s p o n s e o f

16

h e i g h t g ro w th to c o n d i t i o n of re d u c e d r a i n f a l l on y e llo w p o p l a r i s much
g r e a t e r on s o i l s w i t h a r e l a t i v e l y h a r d and im perv io us B h o r i z o n ; t u l i p
p o p l a r showed b e t t e r g ro w th on n o r t h e r l y th a n on s o u t h e r l y s l o p e s .

In

g e n e r a l , t h e h e i g h t g ro w th of t u l i p p o p l a r was r e l a t e d to d e p th o f th e A
s o il h o riz o n .

F o r y e llo w p o p l a r , 35 p l a n t a t i o n s w ith an A h o r iz o n d e p th

o f s e v e n in c h e s o r o v e r grevr 30 p e r c e n t more th a n Ul com parable p l a n t a ­
t i o n s w i t h a c o r r e s p o n d in g d e p th of l e s s th a n sev e n in c h e s .

B in e p l a n ­

t a t i o n s on s i t e s abandoned s i x y e a r s o r more grew 1*5 f e e t a s compared
w i t h O.g f e e t on ^1 p l a n t a t i o n s l o c a t e d on s i t e s abandoned l e s s t h a n s i x
years.

The d r y - y e a r p l a n t i n g s o f y e llo w p o p l a r showed a marked r e d u c t i o n

in g ro w th as compared to w e t- y e a r p l a n t i n g s .

Yellow p o p l a r d r y - y e a r

p l a n t i n g s grew a s w e ll as w e t- y e a r p l a n t i n g s on f r i a b l e s o i l , b u t o n ly
62 p e r c e n t and

36 p e r c e n t a s w e ll r e s p e c t i v e l y on p l a s t i c and s t i f f s o i l s .

P e a r s o n (1930) a tte m p te d to a s c e r t a i n w h ether t h e u p p e r f o o t o f s o i l
a c t u a l l y becomes d r i e r un der o r n e a r g ro up s of t r e e s , th a n in open s i t u a ­
tio n s.

H is r e s u l t s were o b ta in e d a t th e S o u th w e ste rn F o r e s t E xperim ent

S ta tio n .

He found i n e v e ry i n s t a n c e t h a t t h e r e was more m o is tu r e a t

d e p th s o f s i x and tv /elv e in c h e s un d er th e t r e e g ro u p s th a n j u s t o u t s i d e
th e crowns to t h e e a s t o r w e s t.

Shade and l e a f l i t t e r p ro b a b ly e x p l a i n

th e h i g h e r m o is tu r e c o n t e n t u nd er th e t r e e s .

P e a rs o n c o n clu d e d t h a t in

f o r e s t s o f th e S o u th w e s t, h e a t a p p e a rs to be s c a r c e l y l e s s im p o r ta n t t h a n
m o istu re .

S o i l m o is tu r e i s a c r i t i c a l f a c t o r in th e e a r l y l i f e of seed­

l i n g s i n t h e S o u th w e s t, b u t a f t e r t h e r o o t s have p e n e t r a t e d a f o o t or
more t h e e f f e c t s o f d e f i c i e n t m o is tu r e a r e m a n if e s t e d more in slow grow th
th a n i n a c t u a l d e a t h .

17

K ozlo w sk i (19^9) s t u d i e d th e e f f e c t s o f s h a d in g on a p p a r e n t p h o to ­
s y n th e s is f o r s e e d lin g s of t u l i p p o p la r.

I n o r d e r t o t e s t th e e f f e c t o f

re d u c e d l i g h t i n t e n s i t y on th e p h o t o s y n t h e t i c c a p a c i t y of t u l i p p o p l a r ,
s e e d l i n g s o f t h i s s p e c i e s were grown u n d e r c h e e s e c l o t h sh ad es a t f i v e
d iff e r e n t lig h t in te n sitie s*

P h o to sy n th e tic r a t e s o f t u l i p p o p la r,

e x p r e s s e d a s m illi g r a m s o f C0? p e r s q u a r e d e c im e te r o f f o l i a g e p e r h o u r,
were d e te r m in e d and a n a ly z e d s t a t i s t i c a l l y from a L a t i n s q u a re arrangem ent*
An a n a l y s i s o f v a r i a n c e i n d i c a t e d no r e a l d i f f e r e n c e s c o u ld he a t t r i b u t e d
to t h e s h a d in g p r e t r e a t m e n t a lon e*

P h o t o s y n t h e t i c r a t e s o f y e llo w p o p l a r

shoved no s i g n i f i c a n t d i f f e r e n c e s betw een sh ade grown and l i g h t grown
groups.

He found t h a t y e llo w p o p la r re a c h e d a v e r y h ig h p e r c e n t a g e o f

p h o t o s y n t h e s i s a t low l i g h t i n t e n s i t y .

The e f f e c t o f l i g h t i n t e n s i t y

was s t a t i s t i c a l l y s i g n i f i c a n t f o r p i n e and r e d m aple, b u t n o t f o r t u l i p
p o p la r.
E l l i o t t (1915) p o i n t s o u t t h a t tw o -y e a r s e e d l i n g s grew as w e ll as
c o u ld be e x p e c te d f o r th e f i r s t y e a r i n an open f i e l d b o rd e re d on one
end and a lo n g i t s two s i d e s by v i r g i n f o r e s t s which c a s t a shadow o v er
t h e b o r d e r o f th e f i e l d .

At th e end o f th e f o u r t h y e a r p r a c t i c a l l y a l l

were dead e x c e p t th o s e e n jo y in g th e shade o f th e a d j a c e n t f o r e s t ; th e
c o n d i t i o n o f th o s e i n p a r t i a l shade v a r i e d in th e r a t i o o f t h e i r n e a r n e s s
to t h e f o r e s t ; th e p l a n t s in th e rows n e x t to t h e woods b e in g f a r th e b e s t .
E l l i o t t s u rm is e d t h a t th e " f o r e s t f l o o r " had som ething to do w ith th e
re su lt.
Ho m a t t e r how e x a c t i n g f o r l i g h t th e t u l i p t r e e may be when p e s t
th e age o f i t s in f a n c y , i t can have to o much l i g h t and s u n s h in e in i t s
e arly l i f e .

He s u g g e s t s r e d p in e or European l a r c h as " n u rse t r e e s " f o r

18

t u l i p p o p l a r p l a n t a t i o n s , s e t o u t ©, few y e a r s b e f o r e th e t u l i p t r e e s to
g iv e th e n eed ed s h a d e , t h e s e to be p l a n t e d in a l t e r n a t e rows o r a l t e r ­
n a t e l y i n th e ro w s.
in t h i n n i n g .

I f p u re t u l i p i s d e s i r e d , remove th e n u r s e t r e e s

E l l i o t t say s t h a t young t u l i p p o p l a r must have a c e r t a i n

amount o f l i g h t i n e a r l y l i f e , b u t n o t too much, and in l a t e r l i f e a l l
th e l i g h t t h e y can g e t .

19

HISTORY OF RUSS FXPHRIMMTAL F0R3ST

The sam plin g a r e a u n d e r c o n s i d e r a t i o n r e p r e s e n t s a f o r e s t p l a n t a ­
t i o n i n Cass County, s o u th w e s te r n M ich ig an, which was p l a n t e d to t u l i p
p o p l a r "by Mr. F r e d Russ in 193&* u s in g h a n d - p l a n t i n g m ethods.

The Russ

F o r e s t o f 5 SO a c r e s was d o n a te d to M ichigan S t a t e C o lleg e in 19^2 hy
Mr. F r e d

Russ o f C a s s o p o lis , M ichigan.

I t in c lu d e s most o f th e a r e a

f o r m e r l y known as th e Newton Farm, an e a r l y government l a n d

g r a n t to

th e Newton f a m ily in whose hands t h e p r o p e r t y rem ain ed f o r 99 y e a r s .
Some 220 a c r e s a r e co v ered w ith m ature tim b e r and 320 a c r e s a r e in
p la n ta tio n s.

An e x t r a c t from th e d i a r y o f Mr. F re d R uss, d o n o r, i s

q u o te d a s f o l l o w s :
" I n J u n e , 1935» 1 bought a c r e s o f th e Newton Farm —
known a s th e Newton Woods. There were a b o u t 2^0 a c r e s o f woods
on th e p a r t I b o u g h t.
Soon a f t e r th e purcha.se I d e c id e d to p l a n t th e n o r t h h a l f
of th e s o u t h e a s t q u a r t e r s e c t i o n 29 to T u l i p s . This SO a c r e s
had ab o u t e i g h t a c r e s o f young t r e e s m o s tly Beech and Maple
i n th e s o u th w e s t c o r n e r . The r e s t o f t h e la n d had been r u n
q u i t e b a d l y . I t was la n d where T u l ip s grew n a t u r a l l y and th e
SO a c r e s j u s t s o u t h o f i t has some o f th e l a r g e s t T u l ip s in
t h i s p a r t o f M ich ig an . The w a te r l e v e l on t h i s la n d i s a b ou t
s i x f e e t below th e s u r f a c e . I t i s a s i l t sand w ith some c l a y
in t h e s u b s o i l .
I t was p r o b a b ly a la k e bottom a t one t i m e . "
The l a t t e r p o r t i o n of th e above d i a r y e x t r a c t r e f e r s to t h e a r e a
in which th e p r e s e n t i n v e s t i g a t i o n was c a r r i e d o u t .

With th e excep­

t i o n o f Mr. R u s s 1 d i a r y and s e v e r a l p e r s o n a l a c c o u n ts g iv e n bj?" l o c a l
r e s i d e n t s , th e in f o r m a t io n c o n c e rn in g t h i s p l a n t a t i o n i s r a t h e r s c a n t .
The o n ly o t h e r in f o r m a t io n r e l a t i v e to th e grow th and c o n d i t i o n of
t h i s p l a n t a t i o n i s a s u r v i v a l and g ro w th s tu d y made in 19^9 by

20

Mr* C. I n g e r s o l l A r n o ld , F o r e s t e r , Russ

F o rest.3

T his s tu d y i s r e s t r i c t e d

to h e i g h t and d i a m e t e r m easurem ents and e x t e n t o f s u r v i v a l f o ll o i- ’ing
p a th o lo g ic a l in ju ry .

No a tte m p t was made in th e above r e p o r t to d e t e r ­

mine th e c au se o r c a u s e s f o r d i f f e r e n c e s in h e i g h t grovrth, o t h e r th a n
sp ec u la tio n .

3.

A rn o ld , C. I n g e r s o l l . E a r ly S u r v i v a l , Growth, and D is e a s e in
T u l ip Tree P l a n t a t i o n s in S o u th e rn M ich ig an . U n p u b lish ed
m a n u s c r ip t . M ichigan S t a t e C o lle g e , J a n u a r y , 19^9*

21

DESCRIPTION OP EXPERIMENTAL AREA,

A l l d e s c r i p t i v e d a t a f o r th e p l a n t a t i o n •under c o n s i d e r a t i o n as v e i l
as i n f o r m a t i o n on t h e hardwood f o r e s t a d j a c e n t to th e e x p e r im e n ta l a r e a
r e f e r to a 15 y e a r o ld -2 0 a c r e mixed t u l i p p o p l a r - c a t a l p a p l a n t a t i o n
(P ig . 3 ) .

T h is a r e a l i e s w i t h i n t h e Gray-Brown P o d z o lic s o i l g rou p of

s o u th w e s te r n M ich ig an .

The to p o g ra p h y i s m a in ly l e v e l o r g e n t l y undu­

l a t i n g w i t h an e l e v a t i o n o f a p p r o x im a te ly 900 f e e t above s e a l e v e l .

The

e x p e r im e n t a l a r e a c o n s i s t s o f an outw ash p l a i n and o t h e r sandy d r i f t of
g la c ia l o rig in .

The s o i l was form ed from sand and g r a v e l d e p o s i t e d by

w a te r i s s u i n g from t h e i c e b o r d e r betw een th e in n e r and o u t e r r i d g e s of
th e Kalamazoo M o ra in e.
b o u ld e rs or s to n e s .

S o i l s in t h i s a r e a a r e g e n e r a l l y f r e e from l a r g e

The s o i l s on th e e x p e r im e n ta l p l o t a r e a c i d v a r i a n t s

o f t h r e e r a t h e r c l o s e l y r e l a t e d s o i l ty p e s , th e Pox sandy loam, Warsaw
sandy loam , and B ronson sandy loam (Map 1 ) .

In i s o l a t e d s p o t s , loam

o r c la y e y loam may o v e r l i e t h e g r a v e l l y s u b s o i l as a r e s u l t of p a s t
m ixing o f t h e p r o f i l e by p lo w in g .

The a r e a i s d r a i n e d by m eandering

D ovagiac Creek and t h e o v e r a l l d r a in a g e i s m oderate t o good, w ith th e
e x c e p tio n o f s e v e r a l d e p r e s s i o n s p o t s .

D e tailed p r o f i l e d e s c rip tio n s

o f each s o i l ty p e a r e in c lu d e d f o r r e a d y r e f e r e n c e to ed ap h ic and
m ic ro b ia l r e la tio n s h ip s .
The f i e l d s in q u e s t i o n had be en h e a v i l y farm ed f o r many y e a r s p r i o r
to t h e t u l i p p o p l a r p l a n t i n g .

Very l i t t l e a t t e n t i o n had b e en g iv e n to

r e b u i l d i n g t h e s o i l w i t h f e r t i l i z e r of any t y p e .

As a r e s u l t , t h e s o i l s

v e re so d e p l e t e d t h a t f o r th e l a s t few y e a r s p r i o r to t h e d is p o s a l, o f th e

22

MAP 1 .

S O IL S MAP OF THE PLANT AT I ON-GROWN
T U L IP POPLAR EXPERIMENTAL AREA WITH IT S
CORRESPONDING SOIL BOUNDARIES

N

B r a d y s a n d y lo a m
a c id v a ria n t

LEGEND:

'
B ronson
s a n d y lo a m
a c id
v a ria n t
A IV
W

W arsaw l o a m
a c id v a ria n t
A III

Fox s a n d y lo a m
a c id v a ria n t
AI

A II

-A -

c lim a tic
S ta tio n

S c a le : l"

= 220'

23

li&flYiLLOW POPLAR
^

L IR IO D fN O R O N T U U P IF B * * -

L
Sr
H

,f

8

p | \ N T f f i BY M R. R U S S IN I f t 8 _

tm

1

F ig . 3 .
A g e n e r a l view o f th e e x p e r im e n ta l a r e a lo o k in g s o u th w e s t.
T his p h o to was t a k e n A p r i l 19, 1952, p r i o r to "budding o f th e t r e e s .
Note t h e a b se n c e o f c u l t i v a t i o n betw een rows and th e e x t e n t o f
fo rest l i t t e r .
T h is p a r tic u la r * p o r t i o n o f th e 15 y e a r o l d - 20 a c r e p l a n t a t i o n
i s d e s i g n a t e d as A rea l,Y", o r th e a r e a o f po o r h e i g h t g ro w th.

MAP NO. l a

2k

MAP OF THE PROBLEM AREA AND ADJOINING LANDS

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25

p r o p e r t y "by th e o r i g i n a l owner, t h e le n d was u n a b le to p ro d u c e p a y in g
cro p s,

“Wheat and c o rn were th e two c h i e f c ro p s grown, and no th o u g h t

was g i v e n to c ro p r o t a t i o n o r s o i l e n r i c h i n g a g e n t s .

Where th e s o i l

had n e v e r be en u s e d f o r a g r i c u l t u r a l p u r p o s e s , t h e to p s o i l was a. r i c h ,
b l a c k , s a n d y - c l a y loam o c c u r r i n g a s a rem nant o f th e o l d p r a i r i e o f
s o u th w e s te r n M ich ig an .
I n 193$» tw en ty a c r e s o f t u l i p p o p l a r were p l a n t e d on t h e Sg- of
N-Jr o f SBy o f Sec 29, T^S, RlUw, Oass County, M ich igan.

These t r e e s

were home grown by Mr. Russ and p l a n t e d in th e s p r i n g .

T ree s were s e t

l ^ ' S ’1 a p a r t w ith s t a g g e r e d rows 7 ,^ n a p a r t , and c u l t i v a t e d th e f i r s t
year o n ly .
year.

T here was a v e ry low m o r t a l i t y o f young s e e d l i n g s th e f i r s t

In 1939» c a t a l p a t r e e s were p l a n t e d in rows betw een t h e t u l i p

p o p l a r and were n o t c u l t i v a t e d .
g ro w th and s u r v i v a l .

These t r e e s have s i n c e shown v e ry p o o r

By O c to b e r, 19^1, th e t u l i p p o p l a r t r e e s were

m o s tly f o u r f e e t to e i g h t f e e t t a l l w ith some o f them tw e lv e f e e t or
m ore.

The f i r s t , t h i r d , f i f t h , and s e v e n th rows a c r o s s th e n o r t h end

o f t h e p l a n t a t i o n were grown from see d ta k e n from t h e l a r g e t u l i p p o p l a r
s o u th o f th e p l a n t a t i o n .

The t o t a l number o f t u l i p t r e e s l i v i n g and

dead in t h e e n t i r e tw e n ty a c r e s i s £ft-63» o r *4-23 t r e e s p e r a c r e .

R e fe re n c e

to Maps l a and 2 - g i v e an a c c u r a t e d e s c r i p t i o n o f th e e x p e r im e n ta l a r e a
and th e a d j a c e n t hardwood s t a n d .

An a e r i a l p h o to g ra p h ( F i g . h) ta k e n in

1950 has been in c lu d e d t o show t h e f o r e s t c o v e r and s u rro u n d in g la n d .

The 15 y e a r o ld -2 0 a c r e p l a n t a t i o n ru n n in g 660' e a s t - w e s t and 1320'
n o r t h - s o u t h i s b o r d e r e d by a d e n s e , m a tu re , mixed hardwood f o r e s t l o c a t e d
n o r t h , s o u t h , and w est o f th e p l a n t a t i o n .

Those t u l i p p o p l a r t r e e s which

a r e p l a n t e d c l o s e to th e f r i n g e o f Woods A, B, and C (waps l a and 2) a r e

26

one and. o n e - h a l f to two tim e s t h e a v e r a g e h e i g h t o f t r e e s o f t h e same a g e,
d e n s i t y , and same p l a n t a t i o n f u r t h e r removed from t h e woods (T a b le 1 ) .
The a v e r a g e d ia m e te r g row th i s one and o n e - h a l f tim e s g r e a t e r on t r e e s
l o c a t e d c l o s e t o t h e o ld - g r o w th vn od s.

This o b s e r v a t i o n of th e d i f f e r ­

ence in h e i g h t g ro w th th u s n e c e s s i t a t e s th e e s ta b lis h m e n t o f a l i n e to
d i s t i n g u i s h t u l i p t r e e s l y i n g i n s i d e and o u t s i d e t h i s l i n e .

k

The

" i n f l u e n c e l i n e " i s u sed to d e s i g n a t e p o s s i b l e cau se from e f f e c t .

T his

term was s e l e c t e d in o r d e r to a v o id any p r e s u p p o s i t i o n as to t h e s o u rc e
o f th e c a u se f o r re d u c e d o r in c r e a s e d h e i g h t g ro w th on o p p o s i t e s i d e s o f
th e " i n f l u e n c e l i n e . "

Having e s t a b l i s h e d th e f a c t from o b s e r v a t i o n t h a t

th e d i f f e r e n c e in h e i g h t grow th is s t r i k i n g l y marked, th e term " in c id e n c e "
was s e l e c t e d to d e n o te a cau se o r s e t o f c au ses f o r t h i s d i f f e r e n c e , b u t
n o t y e t v e r i f i e d by i n v e s t i g a t i o n . ^

A c c o rd in g ly , f o u r s t r a i g h t - l i n e

t r a n s e c t s were ru n (two in each c a r d i n a l d i r e c t i o n )

in o r d e r to t a l l y

th e h e i g h t s and d ia m e te r s of t u l i p t r e e s along t h e s e t r a n s e c t s (Map 2 ) .
Some c r i t e r i a was n eed ed to d e s c r i b e t h e s e t r a n s e c t s in term s o f b o th
i n f l u e n c e and in c i d e n c e , and f o u r c l a s s e s o r d e g re e s o f in c id e n c e were
s e t up f o r e ach t r a n s e c t i n t a b u l a r form (T ab le 1 ) .

4.

In t h i s s t u d y , t h e " i n f l u e n c e l i n e " of th e woods i s u se d to
d e n o te an e f f e c t o r r e s u l t , so as to p r e c l u d e any p re s u p ­
p o s i t i o n of i t s cau se o r c a u s e s .

5.

The te rm , " i n c i d e n c e , " i s used t o d e n o te some c a u s a l f a c t o r
or se t of fa c to rs .
These c a u s e s mar be in term s o f p r o t e c ­
t i o n o f f e r e d by t h e woods, such as s h a d in g , re d u c e d tem per­
a t u r e , re d u c e d e v a p o r a t i o n , o r re d u c ed wind, v e l o c i t y .

27
MAP NO. 2

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28
TABLE 1.
INCIDENCE CRITERIA
T ransect
Number

A verage H e ig h t i n R e l a t i o n
t o " I n f l u e n c e " L in e

D i r e c t i o n and E x te n t o f
I n c id e n c e Along T r a n s e c t

O u ts id e

In sid e
1

^ 7 .0 ± ^ . 2 *

2 3 .5 ± S . 5*

From SW p l u s no in c id e n c e

2

3 6 . 0 ± lH .O '

2 5 .0 i

8.3 *

From S and SW

3

2 3 .0 ±

7 .1 '

1 7 .1 t

6.11

No in c id e n c e N, S, and E
(some in c id e n c e W)

if

2 8 .0 ±

9 *2 '

1 9 .0 i

2.5'

I n c id e n c e S p l u s no
in c id e n c e from S

A verage

3 3 .5 1 s . 6 *

1 9 .8 ± 6 . 3 '

U sing t h e above in c id e n c e c r i t e r i a as a "basis, th e a v e r a g e h e i g h t s and
d ia m e te r s a s w e ll a s th e h e i g h t s and d ia m e te r s o f i n d i v i d u a l t r e e s were
p l o t t e d to show t h e e f f e c t s of p r e s e n c e o r a b se n c e of woods on o p p o s i t e
s i d e s o f th e " i n f l u e n c e l i n e , "

I n a d d i t i o n , p r o f i l e diagram s were p l o t t e d

to s c a l e in o r d e r to f u r t h e r b r i n g o u t th e r e l a t i o n s h i p o f th e in c id e n c e
c r i t e r i a u s e d , and t h e a p p a r e n t e f f e c t o f t h i s in c id e n c e .

The s ta n d a r d

d e v i a t i o n was computed f o r h e i g h t and d ia m e te r in a l l f o u r t r a n s e c t s on
b o th sid es of th e " in flu e n c e l i n e . "
F o r p u r p o s e s of s i m p l i f i c s . t i o n and f u r t h e r r e f e r e n c e to t h e two a r e a s
s e p a r a t e d by th e " i n f l u e n c e l i n e , " two d i s t i n c t p o r t i o n s of th e experim en­
t a l a r e a e x i s t ass
AREA X - The a r e a e x h i b i t i n g good h e i g h t g ro w th , l i t t l e o r no
s u n s c a l d , good d ia m e te r g ro w th, and l y i n g a d j a c e n t to
Woods A and B. ( F i g s . U-, 5> a &d 6 ) .
AREA Y - The a r e a e x h i b i t i n g p o o r h e i g h t gro w th , extrem e
s u n s c a ld w ith su b se q u e n t wind b r e a k a g e , p o o r d ia m e te r
g ro w th , end o c cup yin g a p o s i t i o n in th e c e n t e r of th e
p l a n t a t i o n d i s t a n t from th e o ld -g r o w th woods.
(F ig s. 3,
and 7 ) .

29

P i g . H.
An a e r i a l p h o to g ra p h ta k e n August 10, 1950, showing
t h e e x p e r im e n ta l p l a n t a t i o n and a d j a c e n t m a tu re , mixedhardwood f o r e s t . A w h ite arrow d e s i g n a t e s th e r e c t a n g u l a r
20 - a c r e e x p e r im e n t a l p l o t .
X s

A rea o f good h e i g h t grow th

Y -

A rea o f p o o r h e i g h t grow th
N
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30

G r a p h ic a l R e p r e s e n t a t i o n o f Pour
S t r a i g h t - L i n e T r a n s e c t s TaJcen in th e E x p e rim e n ta l A rea **

** T r a n s e c t number d e s i g n a t i o n s c o rre s p o n d to
th e same t r a n s e c t s shown on Map 2.

31
TRANSECT NO. 1
100

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80

H t . 60
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40
T u lip P o p la r

20

PROFILE DIAGRAM ALONG A SOUTH TO NORTH TRANSECT
SHOWING INCIDENCE FROM SOUTHWEST PLUS NO INCIDENCE
|<-----------------------------------

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TRANSECT NO. 2

100
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80

O ld
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H a rd w o o d

H t . 60
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20

PROFILE DIAGRAM ALONG A WEST TO EAST TRANSECT
SHOWING INCIDENCE FROM SOUTH AND SOUTHWEST
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SD = Standard
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32

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33

TRANSECT N O . 1

3^

fig . 5 .
A view ta k e n in A rea X (good h e i g h t g ro w th ) . The a v e ra g e
d ia m e te r o f t u l i p p o p l a r i n t h i s a r e a i s 6 .3 in c h e s w ith an
a v e r a g e h e i g h t o f ^7-0 f e e t . Note t h e o ld g row th hardwood
(Woods ,,Att) in t h e "background a d j o i n i n g t h e p l a n t a t i o n .

35
TRANSECT NO.

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TRANSECT NO . 2

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TRANSECT WITH TREES OP THE SAME AGE

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37

F ig . 6 .
A t y p i c a l view o f A rea X lo o k in g n o r t h w e s t . The c a t a l p a
t r e e i n t e r p l a n t i n g shows v e r y p o o r g ro w th . Compare t h e l e a f l i t t e r
on t h e f o r e s t f l o o r w ith t h e l i t t e r shown in F ig . 3* T h is photo
was ta k e n in A p r i l , 1952, p r i o r to budding o f th e t r e e s . Uo su n s c a l d i s o b s e r v a b le in t h i s a r e a .

38
TRANSECT NO. 3

20
T u lip P o p la r
15
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10
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PROFILE DIAGRAM ALONG A WE3T TO EAST TRANSECT
SHOVING- ABSENCE OF INCIDENCE N, S , AND E .

TRANSECT NO. 4

100
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PROFILE DIAGRAM ALONG A SOUTH TO NORTH TRAN3E
SHOWING INCIDENCE FROM SOUTH PLUS NO INCIDENC
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A view taken in th e a rea o f poor h e ig h t growth (Area Y ).
Sunscald i s o b serv a b le on th e t u lip p op lar to th e r ig h t o f th e
p h o to . Note th e dark p a tch es appearing as burns; th e s e are mats
o f Haircap Moss (Polytrichum commune H edw.). The t u lip poplar
in t h is area e x h ib it s e x te n s iv e sprout growth from the base o f
th e t r e e s ; t h i s abn orm ality i s th e r e s u lt o f su n sca ld and tr e e
c r ic k e t a c t i v i t y . The average h e ig h t o f tr e e s in t h is area is
17.1 f e e t w ith an average diam eter o f 3
i nches .

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44

SCOPE OF EXPERIMMIEAL WOBK
The s tu d y s.s o r i g i n a l l y c o n c e iv e d "by t h e F o r e s t r y D epartm ent in
J u n e , 1951»

d e v is e d to measure th e e d a p h ic and a tm o s p h e ric f a c t o r s

w i t h i n th e t u l i p p o p l a r p l a n t a t i o n .

D uring t h e summer o f 1951 f o u r sample

p l o t s w ere e s t a b l i s h e d a s c l i m a t i c s t a t i o n s .

Two o f t h e s e s t a t i o n s were

l o c a t e d on t h e s o u t h and w est s i d e s of th e p l a n t a t i o n b o rd e re d by woodland
where t h e t r e e s e x h i b i t th e g r e a t e s t h e i g h t g row th ; th e re m a in in g two
s t a t i o n s were l o c a t e d n e a r th e c e n t e r o f th e p l a n t a t i o n where th e t r e e s
show l i t t l e h e i g h t g ro w th .

Measurements ta k e n d a i l y by t h e F o r e s t r y

D epartm ent th r o u g h o u t two grow ing s e a s o n s b e g in n in g in 1951 were th e
fo llo w in g :

( l ) a tm o s p h e ric f a c t o r s , end (2) e d a p h ic f a c t o r s .

The f i r s t

o f t h e s e f a c t o r s in c lu d e measurement o f th e e v a p o r a tio n r a t e by u s e o f
th e L i v i n g s t o n atm om eter b u lb ; a i r te m p e r a tu r e and r e l a t i v e h u m id ity by
u s e o f t h e h y g ro th e rm o g rap h and s l i n g p s y c h r o m e te r .

The e d a p h ic f a c t o r s

s t u d i e d were s o i l m o is tu r e by u se o f Bouyoucos s o i l - m o i s t u r e b lo c k s a t
d e p th s o f s i x and e i g h t e e n in c h e s r e s p e c t i v e l y ; s o i l te m p e r a tu r e was ta k e n
d a i l y u s in g a s o i l therm om eter a t a one in c h d e p th below th e s o i l s u r f a c e .
The f i e l d d a t a on th e above f a c t o r s was measured d a i l y where p o s s i b l e .
A lth o u g h o t h e r s o i l p h y s i c a l d e t e r m in a tio n s were p ro p o s e d in th e
o r i g i n a l p l a n o f th e F o r e s t r y D ep artm en t, th e a c t u a l c o l l e c t i o n and
a n a l y s i s o f t h e s e d a t a were l e f t to th e p r e s e n t i n v e s t i g a t o r .

The f o l l o w ­

ing d e t e r m i n a t i o n s on t h e p h y s i c a l - e d a p h i c f a c t o r s a r e th e j o i n t p r o p e r t y
o f th e F o r e s t r y D epartm ent and th e p r e s e n t a u t h o r : ( l ) P h y s i c a l d e t e r ­
m in a tio n s,

in c l u d i n g t o t a l , c a p i l l a r y , and n o n - c a p i l l a r y p o r o s i t y , volume

w e ig h t, maximum w a te r - h o ld in g c a p a c i t y , s p e c i f i c g r a v i t y , m o is tu re

^5

e q u i v a l e n t , h y g ro s c o p ic c o e f f i c i e n t , s o i l e v a p o r a t i o n , and a mechanical,
a n a ly sis,

F u r t h e r f a c t o r s in c lu d e ( 2 ) chem ica l d e t e r m i n a t i o n s such a,s

o r g a n i c m a t t e r c o n t e n t , pH, t o t a l n i t r o g e n , C/il r a t i o , "base exchange
c a p a c i t y , e x c h a n g e a b le hy d ro g e n , t o t a l b a s e s , and t h e n u t r i e n t c o n te n t
of in d iv id u a l h o riz o n s.
To g i v e g r e a t e r co m p reh en siv en ess and scope to t h e p r o j e c t , th e
f o l l o w i n g b i o l o g i c a l d e t e r m i n a t i o n s were deemed a d v i s a b l e : ( l ) Micro­
b i o l o g i c a l d e t e r m i n a t i o n s , which were in c lu d e d to show q u a n t i t a t i v e s o i l
o rg a n ism d i f f e r e n c e s f o r b o th th e a r e a o f good h e i g h t grow th (A rea X) and
p o o r h e i g h t grow th (A rea Y) w ith r e f e r e n c e t o :
a . D epth o f s o i l h o r iz o n
b . Seasonal v a r ia tio n

in m i c r o b i a l c o u n ts

c . The pH in r e l a t i o n

to m ic r o b ia l c o u n ts

d . M o is tu r e c o n te n t in r e l a t i o n to abundance o f organ ism s
e . The numbers o f f u n g i , b a c t e r i a , and a c tin o m y c e te s as
r e l a t e d t o t h e e co lo g y o f each a r e a .
I n o r d e r t o o b s e rv e th e e f f e c t s

o f th e h e rb a c e o u s v e g e t a t i o n

upon

m i c r o b i a l and e d a p h ic f a c t o r s , a s y s t e m a t i c g r i d sam pling o f th e l e s s e r
v e g e t a t i o n was t a l l i e d and p h o to g ra p h e d th ro u g h o u t th e growing s e a so n as
an in d e x t o t h e s u c c e s s i o n o f f l o w e r i n g
tio n

to th e

p o ssib le c o rre la ­

s o i l m o i s t u r e c o n te n t o f each h a b i t a / t .

O b s e r v a tio n o f t h e stems o f
a t i o n show

p l a n t s and t h e i r

t u l i p t r e e s in th e c e n t e r of th e p l a n t -

t h a t t h e s e t r e e s have extrem e s u n s c a ld damage.

In ord er

to

6 . The term " s u n s c a ld " as u sed h e r e r e f e r s to damage r e s u l t i n g
from an extrem e d e g re e o f f l u c t u a t i o n in te m p e r a tu r e on th e
young b a r k . T his damage may be th e r e s u l t o f combined d e s i c c a t i o n
e f f e c t s and r e p e a t e d p a s s i n g back and f o r t h th ro u g h th e f r e e z i n g
po i n t .

^6

s tu d y t h e e f f e c t and e x t e n t o f t h i s damage to t h e p l a n t a t i o n , a com plete
stem anaJLysis o f i n d i v i d u a l t r e e s was made as w e ll as m a cro sc o p ic c r o s s
s e c t i o n s o f damaged t r e e s , so as to e x h i b i t th e e x t e n t , d a t e o f s u n s c a ld ,
and i t s p o s s i b l e r e l a t i o n s h i p to h e i g h t and d ia m e te r grow th o f th e s t a n d .
To o b t a i n t h e t o t a l scope o f th e e c o l o g i c a l problem a d d i t i o n a l d a t a
were o b t a i n e d on (a ) d e p th to t h e w a te r t a b l e th ro u g h o u t t h e s e a s o n (b)
k i n d and e x t e n t o f f o r e s t l i t t e r (c ) c o n c e n t r a t i o n and p o s i t i o n o f r o o t s
in t h e s u r f a c e s o i l h o r i z o n , and (d) l i g h t i n t e n s i t y m easurements a t
v a r i o u s p o i n t s w i t h i n t h e sam pling a r e a .
The s tu d y as shown by th e above e x p e r im e n ta l c r i t e r i a was in te n d e d
to be com preh en sive in i t s s co p e .
in v e stig a te d c o n sist of:
so il-c h em ica l)

A b ro a d c l a s s i f i c a t i o n of th e p h a se s

(1) L a b o ra to ry e x p e rim e n ts ( s o i l - p h y s i c a l and

( 2 ) F i e l d - p l a n t a t i o n e x p e rim e n ts (grovrth, m ic r o c lim a te ,

and p l a n t s u c c e s s io n ) and ( 3 ) S o i l m i c r o b i o l o g i c a l e x p e rim e n ts ( q u a n t i t a t iv e ).
These p h a s e s w i l l be ta k e n up i n d i v i d u a l l y in th e above named o r d e r .
A summary o f a l l f a c t o r s i s p r e s e n t e d a f t e r d i s c u s s i n g each v a r i a b l e .

*+7

SOIL SMILING TECHNIQUE
L a b o r a to r y E xp e rim en ts - P h y s i c a l and Chemical
Equipment Used
The s o i l sam ples f o r "both t h e p h y s i c a l and chem ical s o i l determinart i o n s were ta k e n w i t h a f i e l d s o i l - c o r e s a m p le r.

T h is sam p ler h a s been

u s e d e x t e n s i v e l y by t h e U n ite d S t a t e s S o i l C o n s e rv a tio n S e r v ic e f o r s o i l s
research .

The ty p e u s e d in t h e s e i n v e s t i g a t i o n s employs

a3x3

in c h

aluminum c y l i n d e r w ith a w e ig h te d d r i v i n g assem b ly.
Sampling P r o c e d u re
P i t s were dug a t e ach sam pling s t a t i o n and each s o i l h o r iz o n o f th e
p r o f i l e was sampled s e p a r a t e l y .

The h o r iz o n sampled was b a se d upon th e

a c t u a l d e p th o f a p a r t i c u l a r h o r i z o n as mapped in t h e f i e l d .
were t a k e n a t o r n e a r f i e l d c a p a c i t y .

A l l samples

The s o i l c o r e s o b t a i n e d were th e n

b ro u g h t i n t o th e l a b o r a t o r y and th e p h y s i c a l and ch em ical d e t e r m i n a t i o n s
made.

Where a m o d i f i c a t i o n i n t h e te c h n iq u e o f making a p a r t i c u l a r

d e t e r m i n a t i o n was n e c e s s a r y , a p p r o p r i a t e n o t a t i o n i s made u n d e r th e
e x p e r im e n ta l method f o r t h a t p r o c e d u r e .
P lo t D e sc rip tio n
The sam plin g a r e a s were s e t up in su ch a manner t h a t a s t a t i s t i c a l
a n a l y s i s c o u ld be a p p l i e d to th e d a t a .

F o r most o f th e s o i l f a c t o r s

i n v e s t i g a t e d , sam ples were ta k e n a t f o u r main c l i m a t i c s t a t i o n s d e s ig ­
n a t e d by Roman n u m e ra ls , as S t a t i o n s I , I I , I I I , and IV.

S t a t i o n s I and I I

a r e l o c a t e d in t h e a r e a o f good h e i g h t grovrth (A rea X) and S t a t i o n s I I I
and IV a r e in th e a r e a o f p o o r h e i g h t grow th (A rea Y ) .

At each main

s t a t i o n , f o u r s u b s t a t i o n s were e s t a b l i s h e d a t random and d e s i g n a t e d as

ks

S u b s t a t i o n s 1, 2 , 3» aud

S o i l h o r iz o n s f o r each p r o f i l e were d e s ig ­

n a t e d i n t h e u s u a l m anner, a s AQ »

e tc .

The above n o t a t i o n f o r each

s o i l sam ple i s a p p l i e d to a l l t h e ed ap h ic f a c t o r s i n v e s t i g a t e d .

Thus, an

i n d i v i d u a l sam ple m ight be d e s i g n a t e d a s I I 3 Ag , which r e f e r s to main
s t a t i o n , s u b s t a t i o n , and s o i l h o r iz o n r e s p e c t i v e l y .

R e fe re n c e to a l l

s o i l p r o f i l e s i s p r e s e n t e d u n d e r th e c a p t i o n R e p r e s e n t a t i v e P r o f i l e and
D e s c r i p t i o n f o r e ac h s o i l ty p e a s shown l a t e r .
S t a t i s t i c a l A n a ly s is o f D ata
The s o i l e x p e rim e n ts ( p h y s i c a l and chem ical) were so d e s ig n e d t h a t
a l l data, c o n c e rn in g a p a r t i c u l a r s o i l f a c t o r c o u ld be s u b j e c t e d to a n a l y s i s
of v a ria n ce .

I n a l l c a s e s , th e v a r i a n c e betw een a r e a s h as been s e g r e g a te d

from t h e t o t a l v a r i a n c e .

The s h o r t - c u t method f o r i n d i v i d u a l d e g re e s of

freedom h a s been u s e d to c a l c u l a t e th e mean s q u a re and E - v a lu e as shown
by S n e d e co r (19^-6).

Experim ents were d e s ig n e d f o r i n d i v i d u a l com parisons

among t r e a t m e n t s , where th e sum o f s q u a r e s f o r n tr e a t m e n t s i s s u b d iv id e d
in t o n - 1 p a r t s , each c o rre s p o n d in g to a s i n g l e d e g re e o f freedom ; t h e s e
p a r t s were th e n t e s t e d i n d i v i d u a l l y a g a i n s t e x p e r im e n ta l e r r o r .

The

r e s u l t s o f t h i s method g iv e a n o t a b l e i n c r e a s e in t h e in f o r m a tio n f u r ­
n i s h e d by th e e x p e r im e n t.

T h is method i s a p p l i c a b l e where th e two sums

a r e made up o f th e same number o f i n d i v i d u a l s .

By comparing th e e r r o r

v a r i a n c e betw een a r e a s , th e p r e s e n c e o r absence o f s i g n i f i c a n t d i f f e r e n c e
can b e d e t e c t e d from t h e E - t e s t .

I n o r d e r to d e te rm in e betw een a r e a s i f

a s i g n i f i c a n t d i f f e r e n c e e x i s t s , i t i s n e c e s s a r y to e x p re ss what c o n s t i t u t e s
a s i g n i f i c a n t d i f f e r e n c e in term s o f th e u n i t in which th e s i l v i c a l f e a t u r e
was m e asu re d .

I n t h e c a s e o f w a te r - h o ld in g c a p a c i t y , th e u n i t i s p e r c e n t

m o i s t u r e ; in t h e c a s e o f a v a i l a b l e c alc iu m c o n t e n t , t h e u n i t i s

49

r a i l l i e q u i v a l e n t s p e r 100 grams o f s o i l .

Thus, "by e x p r e s s i n g in p e r c e n t

m o i s t u r e t h e d i f f e r e n c e betw een s o i l h o r iz o n s o f A rea X and A rea Y, i t i s
p o s s i b l e t o d e te r m in e betw een which s o i l f a c t o r a s i g n i f i c a n t d i f f e r e n c e
e x ists.

The method o f making t h e s e c a l c u l a t i o n s i s shown in t h e fo rm u lae

w hich f o l l o w :
mean s q u a r e t r e a t m e n t
T* v a lu e

mean s q u a re e r r o r

854.00

“

24.4

* *

3 7.07
** S in c e t h e F - v a lu e i s l a r g e r th a n 4 .6 0 o r S .S 6 (from S i g n i f i c a n c e
T a b le ) t h e d i f f e r e n c e betw een a r e a tr e a tm e n t means i s s i g n i f i c a n t a t b o th
t h e f i v e p e r c e n t and one p e r c e n t l e v e l .
The mean s q u a r e t r e a tm e n t f o r A rea X v s . A rea Y i s d e r iv e d from th e
c a lc u la tio n :
( t x - t 2)
k

-

=

C. T.

n
w here:
k r
n z

mean s q u a re
and t 2 “ sum o f i n d i v i d u a l item s
sum o f a l l m easurem ents

C,

4 2

T. - c o r r e c t i o n term

The c o r r e c t i o n term
_

(C .T .) i s o b ta in e d by th e fo rm u la :
m

V• J- •

„

( sum i n d i v i d u a l
1

--- ---—

item s)

— -■■- ■ ■■
■

t o t a l item s
To c a l c u l a t e t h e e r r o r te rm :
E

=

E - I

w here:

S
R

= E rror
z T otal v arian ce

K

“ V a r i a t i o n betw een a r e a s

50

By e x a m in a tio n o f th e m agnitude o f th e F -'v a lu e , th e e x t e n t o f th e
v a r i a t i o n can he i n t e r p r e t e d .

Thus, i f th e F - v a lu e o b ta in e d f o r A rea X

f o r any one s o i l h o r i z o n i s l a r g e in com parison to o t h e r h o r iz o n s o f th e
same s o i l ty p e , most v a r i a t i o n e x i s t s a t t h a t h o r i z o n ; s i m i l a r l y , a sm all
F -v alu e in d ic a te s l e s s v a r i a t i o n f o r a p a r t i c u l a r h o rizo n .
At th e c o n c lu s io n o f th e d a t a o b t a i n e d f o r b o th th e p h y s i c a l and
ch e m ic a l f a c t o r s i n v e s t i g a t e d , a summary t a b l e i s p r e s e n t e d to i n d i c a t e
th e r e l a t i o n s h i p o f F - v a l u e s f o r a l l s o i l v a r i a b l e s t h a t were s t u d i e d .

51

laboratory experiments

P h y s i c a l — Edaphic C h a r a c t e r i s t i c s
1 . M ec h a n ica l A n a ly s is

7

E x p e rim e n ta l Method:
A mechanical, a n a l y s i s o f th e s o i l s in th e e x p e r im e n ta l a r e a was
made "by t h e h y d ro m e te r method, employing th e te c h n iq u e o f Bouyoucos (193&) •
The s o i l sam ples ( l 6 sam ples p e r s t a t i o n tim e s f o u r s t a t i o n s =
were th o r o u g h l y a i r - d r i e d and p a s s e d th ro u g h a two mm. s i e v e .
t r e a t m e n t a f i f t y - g r a m sample was u s e d .

samples)
Por each

To d i s p e r s e th e s o i l th e f i f t y -

gram sam ple was added d i r e c t l y to a s t i r r i n g cup, and d i s t i l l e d w a te r added.
The d i s p e r s i n g a g e n t u s e d was a commercial p ro d u c t known as C algon, a
sodium h ex am e ta p h o sp h a te compound.

S in c e t h i s d i s p e r s i n g a g e n t had n o t

been u s e d p r e v i o u s l y , i t was n e c e s s a r y t o ru n a few t e s t sam ples to d e t e r ­
mine i f t h e amount o f Calgon u s e d p e r sample was c r i t i c a l w ith t h i s p a r t i c ­
u la r s o i l ty p e.

H aving d e te rm in e d by t e s t ru n t h a t th e c o n c e n t r a t i o n o f

d i s p e r s i n g a g e n t u s e d was n o t s i g n i f i c a n t l y d i f f e r e n t betw een u s e o f t e n c c .
to t w e n t y - f i v e c c . i n c l u s i v e , a f i f t e e n c c . Calgon c o n c e n t r a t i o n v/as
employed as a d i s p e r s i n g a g e n t.

A f t e r s o ak in g and s u b se q u e n t s t i r r i n g o f

th e s o i l w ith th e d i s p e r s i n g a g e n t , th e c o n te n t s were th e n p o u re d i n t o th e
s p e c i a l c y l i n d e r , s h a k e n , and th e tim e r e c o r d e d .

A te m p e r a tu r e c o r r e c t i o n

was a p p l i e d to e ach h y d ro m e te r r e a d in g and a summation o f th e r e s u l t s f o r
b o th A re a X and A rea Y i s g iv e n in T able 2.

7. The number p r e c e d i n g th e p h y s i c a l s o i l f a c t o r und er i n v e s t i g a t i o n
c o rre s p o n d s t o th e same f a c t o r summarized s t a t i s t i c a l l y in T ab le 21.

52
TABLE 2.
MECHANICAL ANALYSIS OF FIELD SOILS BY HORIZON IN AREA X AND AREA Y
P ercent
A rea X ( S t a t i o n s I - I I )
S o i l H o riz o n

Sand

S ilt

IAX
A2
b2
B-2

6 1 .9
7 6 .7
7 3 .6
91.6
9 4 .0

2 1 .9
9*1
6.0
1.0
0.0

3S .I
23.3
26.4
2 .4
6.0

3*0
1*7
1.0
1 .0
0.0

13.2
12.5
1 9 .4
6 .4
6.0

IIA 1
a2
b2
B-t

6 1 .1
63.2
76.0
Sg.O
9 4 .0

22.6
17*9
4 .0
0.0

32.9
36.s
24.0
1 2 .0

13.1
16.2
1S.0

0.0

6.0

3*2
2 .7
2.0
2. 6
0.0

4 3 .1
3 6 .3
29.6
6.0
5*o

3*2
7 .2
2.1
1.0
0.6

15.4
1 8.0
23.1
5.0
4 .4

3 3 .5
37*3
3 2 .4
10.0

3*2
2.5
2.0
0.6
1.0

1 4 .9
19.1
2 0.4
9 .4
4 .4

S ilt

p l u s Olay

Clay

F in e Clay

9.4
6.0

A rea Y ( S t a t i o n s I I I - I V )
IIIA i
a2
b2

5

IVAX
a2
b2
Cl

56.9
61.7
70. 4
9 4 .0
95*0

2 4 .5
13.1
4 .4
0.0

61.5
62.7
67.6
90.0
9 4 .6

2 0 .4
15*7
10.0

0.0

0.0
0.0

5.4

D is c u s s i o n o f R e s u l t s
The m e c h a n ic a l a n a l y s i s d a t a r e v e a l th e o v e r a l l sandy n a t u r e o f
sam ples ta k e n in s i x t e e n d i f f e r e n t l o c a t i o n s .

V a r i a t i o n in t e x t u r e a cc o rd ­

in g t o t h e U n ite d S t a t e s D epartm ent o f A g r i c u l t u r e t e x t u r a l c l a s s i f i c a t i o n
i s shown on th e R e p r e s e n t a t i v e P r o f i l e D e s c r i p t i o n s f o r each s o i l t y p e .

The

v a r i a t i o n i n t e x t u r e i s most marked in th e amount o f f i n e c la y in th e A-j_
and Ag h o r i z o n s when c o n t r a s t i n g Area, X w ith A rea Y.

This v a r i a n c e in th e

f i n e c l a y c o n te n t i s th e h a s i s f o r t h e d i s t i n c t i o n o f t h r e e s o i l ty p e s

53

o f th e same d r a in a g e c a t e n a .

The t h r e e main s o i l ty p e s r e p r e s e n t e d a r e

a c i d v a r i a n t s o f t h e Pox sandy loam , Bronson sandy loam, and 'Warsaw sandy
loam.

The p r o f i l e d e s c r i p t i o n s "bring o u t t h e s e r e l a t i o n s h i p s more c l e a r l y

(P ig s. 9 -1 2 ).

To d e te r m in e t h e e x t e n t and s i g n i f i c a n c e of th e v a r i a t i o n

in t h e in d iv id u a l, s e p a r a t e s , an a n a l y s i s o f v a r i a n c e was made f o r f i n e
c l a y , s i l t p l u s c l a y , and t o t a l s a n d , f o r b o th A rea X and A rea Y (T a b le s
3, 4 , and 5 ) .
TABLE 3 .
ANALYSIS OP VARIANCE FOR MECHANICAL ANALYSIS AREA X v s . AREA Y
T e x t u r a l G lass - P in e c l a y ( l e s s th a n 2 m icron d i a . )
B a s i s : 32 samples
H o riz o n
^1

^2

Source

D egrees o f Freedom

Sum o f Squares

Mean Square

T otal
X vs Y
E rror

15
1
l4

36 . 1 0
16 . 0 0
20.10

16.00
1.43

1 1 . 1 **

T o tal
X vs Y
E rror

15
1
l4

^ 9 .3 9
184.96
264.43

184.96
18 .80

l 4 . 6 **

p

B a s i s : k samples
B2

5

cl

T o tal
X vs Y
E rro r

3
1
2

13.93
9 .3 0
U.63

9 .3 0
2.31

4 .0 2

T o tal
X vs Y
E rror

3
1
2

1 4.6 7
.49
14.18

.49
7.09

.07

T otal
X vs Y
E rror

3
1
2

2.56
2.56
0.00

2.56
0.00

0.00

** S i g n i f i c a n t a t 5$

1$

The a n a l y s i s o f v a r i a n c e f o r th e f i n e c la y f r a c t i o n is h ig h ly s i g n i f g
i c a n t a t b o th th e 551 and Vi l e v e l in t h e Aj and A2 h o r i z o n s .
In v e stig ato rs
such a s A l b e r t (1925) and B ornebusch (1931) have f r e q u e n t l y r e p o r t e d t h a t

5^
t h e c o n t e n t o f m a t e r i a l s m a l l e r t h a n . 2 mm. in sandy s o i l s has an im p o rtan t
b e a r i n g on s i t e q u a l i t y .
table

4.

ANALYSIS OF VARIANCE FOR MECHANICAL ANALYSIS AREA X v s . AREA Y
T e x t u r a l C la ss - S i l t p l u s c la y
B a s is : 32 samples
H o riz o n
A1

a2

b2

c.

B-jj

C

Source

D egrees o f Freedom

Sum o f Squares

Mean Square

F

T o tal
X vs Y
E rror

3
1
2

16.19
5 .2 9
10.90

5.29
5 .4 5

.97

T o tal
X vs Y
E rror

3
l
2

1 5 1 . U9
59.86
91.63

59 .86
4 5 . SI

1.31

T o tal
X vs Y
E rror

3
l
2

U2 . 9 U
3 6 . 1 *+
6 . so

36.14
3 .4 o

10.62

T o tal
X vs Y
E rror

3
l
2

19.32
4 .s4
i4 .4 g

4 .S 4
7 .2 4

.67

T o tal
X vs Y
E rror

3
l
2

.72
.64
.o s

.64
.04

16.00

S. When u s e d in d i s c u s s i n g e x p e r im e n ta l d a t a , th e word " s i g n i f i c a n t “ ,
i s a p p l i e d in a s t a t i s t i c a l s e n s e . T here a r e v a r i o u s d e g re e s o f
s i g n i f i c a n c e now re c o g n iz e d s t a t i s t i c a l l y , b u t th e two most
commonly u sed a r e a t th e 1# and 5$ l e v e l s . The fo rm er l e v e l , i n i n d i c a t e s t h a t t h e r e a r e n i n e t y - n i n e chances in one hundred t h a t
t h e d i f f e r e n c e in means i s n o t due to random sam pling in a homo­
geneous p o p u l a t i o n . T h is 1$ l e v e l i s r e f e r r e d to as v e ry or
h i g h l y s i g n i f i c a n t . The l a t t e r p e r c e n t l e v e l i n d i c a t e s t h a t t h e r e
a r e n i n e t y - f i v e chances in one hundred t h a t th e d i f f e r e n c e in
means i s n o t due to random sam pling o f a homogeneous p o p u l a t i o n ,
and i s commonly spoken o f a s s i g n i f i c a n t . The F - v a lu e i s a
s t a t i s t i c a l in d e x to d e te rm in e th e m agnitude o f th e s i g n i f i c a n t
l e v e l and w i l l be u t i l i z e d th ro u g h o u t th e re m a in d er o f t h i s
m a n u s c r i p t . The p l o t r e p l i c a t i o n method o f a n a l y s i s w i l l be
fo llo w e d a c c o r d in g to Snedecor (19*4-6).
A lthough t e x t u r e , nor any o th er s in g le s o i l p ro p erty , seldom d e te r ­
mines th e q u a l i t y o f s i t e ,

i t i s g e n e r a l l y re c o g n iz e d t h a t loam and loamy

55

s o i l s a r e more f a v o r a b l e f o r f o r e s t growth, th a n e i t h e r c o a r s e sands o r
fin e c la y s.

I t i s t h e r e f o r e p e r t i n e n t to p o i n t out t h a t th e i n f l u e n c e o f

s o i l t e x t u r e on t h e grow th o f t u l i p p o p l a r may be masked by th e i n f l u e n c e
of o th e r f a c t o r s .

The p r e s e n c e o f a Warsaw loam s o i l ty p e in A rea Y v h e re

th e t r e e s a r e s m a l l e s t i s a rough i n d i c a t i o n t h a t s o i l t e x t u r e a lo n e may
n o t be a l i m i t i n g f a c t o r f o r th e h e i g h t g row th o f t u l i p p o p l a r .

Thus, in

a l l t h e s t a t i s t i c a l a n a ly s e s t h a t f o ll o w f o r a l l s o i l f a c t o r s and o t h e r s ,
t h e a n a l y s i s o f v a r i a n c e i s u sed o n ly to p o i n t o u t s t a t i s t i c a l d i f f e r e n c e s
and n o t t o p o r t r a y t h e i r e c o l o g i c a l s i g n i f i c a n c e .

The r e l a t i o n s h i p o f

t e x t u r e t o o t h e r s o i l f a c t o r s w i l l be b ro u g h t o u t i n s o f a r as t e x t u r e r e ­
l a t e s to a s e t o f i n t e r r e l a t e d s o i l and m o is tu r e phenomena.
TABLE 5.
ANALYSIS OF VARIANCE FOR MECHANICAL ANALYSIS AREA X v s . AREA Y
T e x t u r a l C lass - Sand ( l e s s th a n 1000 m icron d i a . )
B a sis:

32 samples

H o riz o n

Source

D egrees of Freedom

Sum o f Squares

Mean Square

F

A1

T o tal
X vs Y
E rror

15
1
Ik

212,20
21.62
190.61

21.62
13.62

1.61

T o tal
X vs Y
E rror

15
1
Ik

1993.56
237.16
1 7 5 6 .k2
B a s i s : U sam ples

237. I 0
1 2 5 . ko

1.90

T o tal
X vs Y
E rror

3
1
2

3 3 . 6U
6 . SO

3 3 .64
3 .^ 0

9.S9

T otal
X vs Y
E rror

3
1
2

1 9.32
H.gh
ih .

U.sh
7 . 2^

.67

T o tal
X vs Y
E rror

3
1
2

.7 2
. 6^
.OS

. 6U
.oh

16.0

A2

Bpd.

3

_L

56

The g r a p h i c r e l a t i o n betw een com parable d e p th s to a l l s o i l h o r iz o n s
f o r b o t h a r e a s i s s h o rn in F i g . S.

S tu d i e s by Auten (1937 and 19*4-5) u s in g

d e p th o f b o th t h e A and B h o r iz o n s a s i n d i c e s o f s i t e e v a l u a t i o n f o r t u l i p
p o p l a r , have shown no e s t a b l i s h e d r e l a t i o n s h i p betw een t h i c k n e s s o f th e B
h o r i z o n and s i t e in d e x .

The com pactness o r d e n s i t y o f th e B h o r iz o n i s th e

c h a r a c t e r r e s p o n s i b l e f o r h i n d e r i n g w a te r movement and p e r m e a b i l i t y r a t h e r
th a n t h i c k n e s s .

The t h i c k n e s s o f th e A h o r iz o n i s n o t a good c r i t e r i o n o f

s i t e f o r t u l i p p o p l a r ; d e p th to a heavy c l a y s u b s o i l i s a much b e t t e r
m easu re o f t h e p e r m e a b i l i t y o f w a te r .

Auten (19*4-5)

c o r r e l a t i o n f o r d e p th to s u b s o i l and s i t e in d e x .

shown a h ig h

He has shown t h a t on s o i l s

whose d e p th to t i g h t s u b s o i l i s l e s s th a n 2*4- in c h e s would have a s i t e index
o f l e s s th a n 8 5 *

I f t h i s c r i t e r i o n was a p p l i e d to t h e p r e s e n t i n v e s t i g a t i o n ,

th e h i g h e s t s i t e in d e x e x p e c te d f o r th e b e s t h e ig h t grow th would be 82,
assum ing t h a t o t h e r t e x t u r a l and c l i m a t i c c h a r a c t e r i s t i c s were n o t l i m i t i n g .
The r a t h e r s t r i k i n g s i m i l a r i t y o f d e p th to com parable h o r iz o n s and t e x t u r e
i s shown in F i g . 8 .

The d e p th t o s u b s o i l does n o t v a ry m arkedly when con­

t r a s t i n g th e t h r e e r e l a t e d s o i l ty p e s u n d e r i n v e s t i g a t i o n .
A uten (1937) fou n d a p o s i t i v e c o r r e l a t i o n betw een s i t e e v a l u a t i o n and
d e p th of th e u n d i s t u r b e d Aj h o r i z o n f o r s o i l s s u p p o r tin g t u l i p p o p l a r .
P o p l a r was g e n e r a l l y n o t fo u n d on s o i l whose A-^ h o r iz o n was l e s s th a n one
in c h t h i c k , and s i t e in d e x in c r e a s e d w ith t h i c k n e s s o f t h e A^ h o r iz o n between
t h e l i m i t s o f one and e i g h t i n c h e s , a p p ro x im a te ly t h r e e s i t e - i n d e x p o i n t s
f o r e a c h in c h o f A^.
u n d istu rb e d s o i l .

These f i n d i n g s were v a l i d o n ly on th o s e a r e a s hav in g

H is r e s u l t s were b a se d upon th e r e l a t i o n between o r g a n ic

m a t t e r i n c o r p o r a t i o n and i n d i r e c t measure o f s o i l m o is tu r e .
I n th e p r e s e n t i n v e s t i g a t i o n , u s in g A u te n 's c r i t e r i o n of

d e p th , i t

CO

s

Ill
Fl rH

CO

FJ

O

CM

O

rH

rH

/

I
O
X

rH

CO

GRAPHIC RELATIOTT BETWEEN EQUAL-AGED TULIP POPLAR AIR) DEPTH TO
COMPARABLE SOIL KORIZOTI ITT AREAS O
P GOOD AITD POOR
HEIGHT GROWTH

F ig.
8 .
57

rH

_ © r*S
>> +* rd

O

53

would be p o s s i b l e to a c h ie v e a s i t e in d e x o f a p p ro x im a te ly 93 f o r
d om inant t r e e s a t 50 y e a n s .

However, t h i s s u p p o s i t i o n would be v a l i d

o n ly when o t h e r s i t e re q u ir e m e n ts c o u ld be m et, such a.s good s u b s o i l
d r a i n a g e , a d e q u a te s o i l m o is tu r e , and on s i t e s which a r e n o t un du ly ex­
p o s e d to r a p i d s u r f a c e s o i l a i r - d r y i n g .
The p r o f i l e s tu d y o f th e p r e s e n t i n v e s t i g a t i o n r e v e a l s no r e l a t i o n s h i p
to th ic k n e s s of th e B h o riz o n .

However, t h e r e a p p e a rs to be some c o r r ­

e l a t i o n betw een t h e w a t e r - h o l d i n g c a p a c i t y o f th e A h o r iz o n and s u b se q u e n t
s o il-m o is tu re ev ap o ratio n .

These r e s u l t s , in t u r n , a f f e c t p e r m e a b i l i t y

and d r y n e s s o f t h e s u r f a c e

s o i l s in b o th a r e a s .

e l a t i o n betw een th e amount

o f o r g a n ic m a t t e r and f i n e c la y c o n te n t o f th e

T h is s tu d y shows a c o r r ­

A-j_ and A^ h o r i z o n s , w ith r e s p e c t t o s o i l - m o i s t tire r e l a t i o n s h i p s .

These

p r o f i l e c h a r a c t e r i s t i c s a r e s u b s t a n t i a t e d by s t a t i s t i c a l s i g n i f i c a n c e be­
tw een A re a X and A re a Y as
Thus, i t a p p e a rs t h a t

shown i n T ab le 3*
t e x t u r e and o r g a n ic m a t t e r i n c o r p o r a t i o n o f th e

A^ and Ag h o r i z o n s , and t h e i r a t t e n d a n t s o i l - m o i s t u r e h o ld in g c a p a c i t y , i s
d e f i n i t e l y r e l a t e d t o o t h e r c l i m a t i c f a c t o r s such as e v a p o r a tio n , a i r
t e m p e r a t u r e , s o i l t e m p e r a t u r e , and growing s e a s o n p r e c i p i t a t i o n ,
in v e stig a tio n .

in t h i s

The manner in which th e A1 and Ag h o r iz o n s a r e r e l a t e d to

th e r a d i a l and h e i g h t grow th o f t u l i p p o p l a r and th e growing s e a so n p r e ­
c ip ita tio n ,

i s d i s c u s s e d under c l i m a t i c f a c t o r s .

59

SOIL PROFILE DESCRIPTIONS

6o

S o i l P r o f i l e and R e l a te d C h a r a c t e r i s t i c s
A rea X - S t a t i o n I
The s o i l p r o f i l e exposed in t h i s a r e a r e p r e s e n t s t h e s i t e where th e
h e i g h t and d i a m e te r grow th i s g r e a t e s t .

T h is a r e a i s im m ediately a d j a c e n t

t o Woods 11A11 on t h e w est and Woods "B" t o th e s o u th .

There i s no s u n s c a ld

damage to t r e e s on t h i s s i t e ; t h e lo w er b ra n c h e s a r e s e l f - p r u n e d and no
s p r o u t i n g o c c u r s a t t h e b a se o f th e t r e e s .

Numerous su g ar maple s e e d l i n g s

a r e to be fo u n d , and th e l i t t e r i s n o t i c e a b l y g r e a t e r in amount th a n t h a t
fou nd f u r t h e r o u t in th e p l a n t a t i o n .

The h e rb a ce o u s v e g e t a t i o n on t h e

f o r e s t f l o o r i n d i c a t e s s p e c i e s which a r e more a k in to th e a d j o i n i n g woods
th a n t h e f l o r a fo un d in th e a r e a o f p o o r h e i g h t gro w th .
To a d e p th o f a p p ro x im a te ly f i f t e e n in c h e s t h e r e i s a sandy loam o f
a d a r k brown c o l o r .

Below th e A h o r iz o n and i n t o t h e B h o r i z o n , c l a y i s

fo u n d , g r a d in g i n t o a loamy sand a t th e 3^ h o r i z o n .

At a d e p th o f t h i r t y

in c h e s and beyond t h e r e i s a y e l l o w i s h brown s a n d , w ith no lim e p r e s e n t .
The s o i l ty p e in t h i s a r e a i s a Pox sandy loam, a c i d v a r i a n t .

The t u l i p

p o p l a r r o o t zone i s fo u n d e x c l u s i v e l y in th e A^ and A2 h o r iz o n s to a, d e p th
o f a p p r o x im a te ly tw e lv e in c h e s .

Most o f t h e w a te r f a l l i n g on t h i s s o i l i s

removed i n t e r n a l l y ; t h e r e i s a te n d e n c y t o d ry in g o u t under extrem e ex­
p o s u r e , e s p e c i a l l y where t h i s s o i l ty p e i s n o t co v ered w ith t r e e s .

F ig . 9 .
SOILS ANALYSIS

61

REPRESENTATIVE PROFILE AND DESCRIPTION

A rea X - P l o t I

In.

F t.

P ro file

D epth

H orizon

Sandy lo a m . Dark r e d d i s h
b r o w n ( 6 YR 3 / 2 ) . Weak
m edium g r a n u l a r . pH 5 * 5 5

z 4

0M
- 9Alt

-

6

D escrip tio n

8
JO ~ J

9"-15"

A2

1 5 ' ’- 2 3 ”

B2

23”-30”

B3

30"-38”
up

Ci

2

3

Sandy lo a m . B ro w n -d ark
b r o w n ( 7 . 5 YR A / 2 ) . Weak
m ediu m g r a n u l a r t o f i n e
c r u m b . pH 5 . 3 3
Sandy
loam t o san d y c l a y lo a m .
D a r k b r o w n ( 7 . 5 YR 3 / 3 ) . M ed .
t o c o a r s e n u c i f o r m . Some
g r a v e l . D a r k c o a t i n g s on
s t r u c t u r a l f a c e s . pH 5 . AO
Loamy
sand t o s a n d . Reddish
brown
( 6 , 0 YR A / 3 ) . V e r y w ea k
n u c i f o r a t o s i n g l e c c r a i n . Some
s t r a t i f i c a t i o n . No l i m e p r e s e n t
D a r k c o a t i n g s on s t r u c t u r a l
f a c e s . pH 5 . A 2
S a n d . Y e llo w is h brown
10 YR 5 / A . S t r u c t u r e l e s s . No
l i m e p r e s e n t , pH 5 . 1 8

4
S o i l T y p e - Fox s a n d y l o a m , a c i d v a r i a n t
Topography - N e a rly l e v e l
D r a i n a g e - Good
E r o s i o n - None
P e rm e a b ility - M oderately ra p id
C l a s s i f i c a t i o n - C ra y Brown P o d z o l i c
L o c a tio n :

E& o f N-J o f S E i o f S e c 2 9 T5S RlAw
C ass C ou n ty, M ic h ig a n

62

S o i l P r o f i l e and R e l a t e d C h a r a c t e r i s t i c s
A rea X - S t a t i o n I I
The s o i l p r o f i l e exposed in t h i s a r e a a l s o e x h i b i t s t u l i p p o p l a r
o f e x tre m e h e i g h t gro w th i n c o n t r a c t to A rea Y.
t o Woods "B*1 on th e s o u t h .

T h is s i t e i s a d j a c e n t

A gain , t h e r e i s an abundance o f s u g a r maple

s e e d l i n g s , s e l f - p r u n i n g o f low er b r a n c h e s , ab se n c e o f s u n s c a l d , and no
b a sa l sp ro u tin g .

The h e rb a c e o u s v e g e t a t i o n e x h i b i t s s p e c i e s which have

a p p a r e n t l y m ig r a te d from t h e hardwood f o r e s t to th e s o u th .
T h is a r e a i s s i m i l a r to S t a t i o n I w ith th e e x c e p tio n o f a few minor
d i f f e r e n c e s in d e p th to t h e w a te r t a b l e .

The A h o r iz o n i s a d a rk r e d d i s h

brown, which g r a d e s i n t o a loamy sand B h o r i z o n .

A gain, th e C h o r iz o n a t

a d e p t h o f 3 ^ i n c h e s , i s a y e l l o w i s h brown s a n d .

No lim e i s p r e s e n t in

t h e lo w e r p a r t o f th e B h o r iz o n o r t h e G h o r i z o n .

The t u l i p p o p l a r

l a t e r a l r o o t zone i s found e n t i r e l y w i t h i n th e f i r s t t h i r t e e n in c h e s o f
th e p r o f i l e .

As b e f o r e , th e s o i l i s a Pox sandy loam, a c i d v a r i a n t , w e ll

to somewhat e x c e s s i v e l y d r a i n e d .
is removed i n t e r n a l l y .
c o n d itio n s.

Most o f th e w a ter f a l l i n g on t h i s s o i l

T h is s o i l ty p e te n d s t o be d ro u g h ty under exposed

F ig . 1 0 .
SOILS ANALYSIS

63

REPRESENTATIVE PROFILE AND DESCRIPTION

Area X - P lo t I I

In * F t*

P ro file

D epth

H orizon

2 H

0"-8"

4
6

Al

D escription
Sandy l o a m . Dark r e d d i s h
b r o w n ( 6 YR 3 / 2 ) . Weak
medium g r a n u l a r . pH 5 . 3 9

—

a to -

8"-14"

14"-27"

27"-34"

34"-43"
up

A2

Sandy lo a m . B ro w n -d ark brown
( 7 . 5 YR 4 / 2 ) . V e r y w e a k m e d .
g ra n u la r to fin e blo ck y .
Medium p l a t y . pH 5 . 2 0

B2

Sandy loam t o san d y c l a y
l o a m . D a r k b r o w n ( 6 . 5 YR 3 / 3 ) •
Weak c o a r s e b l o c k y . G r a v e l l y
d a r k c o a t i n g s on s t r u c t u r a l
f a c e s . pH 5 . 1 5

B-

Lo amy s a n d . R e d d i s h b r o w n
( 5 . 5 YR 4 / 3 ) . V e r y w ea k c o a r s e
blocky to s in g le g r a in .
G r a v e l l y d a r k c o a t i n g s on
s t r u c t u r a l f a c e s . pH 5 . 1 4
S a n d . Y e l l o w i s h brown
( 1 0 YR 5 / 4 ) . S i n g l e g r a i n .
l i m e p r e s e n t . pH 5 . 4 0

No

S o i l T y p e - Fox s a n d y l o a m , a c i d v a r i a n t
Topography - N early l e v e l 1^ t o N
D r a i n a g e - Good
E r o s i o n - None
P e rm e a b ility - M oderately ra p id
C l a s s i f i c a t i o n - G r a y Brow n P o d z o l i c
L o c a tio n :

Ei of

o f S E j o f S e c 29 T5S R14W
C ass C ou n ty, M ic h ig a n

6k

S o i l P r o f i l e and R e l a te d C h a r a c t e r i s t i c s
A rea Y - S t a t i o n I I I
A p r o f i l e e x po sed in t h i s a r e a i s r e p r e s e n t a t i v e o f th e s i t e f o r
p o o r h e i g h t gro w th o f t u l i p p o p l a r .
th is area.

Eo woods o f any ty p e a r e a d j a c e n t to

Sugar maple s e e d l i n g s a r e a b s e n t , t h e r e i s extrem e s u n s c a ld

damage and s u b s e q u e n t wind b r e a k a g e , b a s a l s p r o u t i n g o f th e t r e e s , and a
p r e d o m in a n tly g r a s s and a n n u a l weed h e rb a ce o u s v e g e t a t i o n .

A lthough t h e r e

i s some o v e r l a p o f h e rb a c e o u s s p e c i e s w ith t h a t o f A rea X, p r a c t i c a l l y no
s p e c i e s o c c u r h e r e which a r e found in t h e o l d grow th hardw oods.
The s o i l ty p e i s a Warsaw loam to sandy loam, a remnant o f t h e o l d
p r a i r i e s o i l o f s o u th w e s te r n M ichigan.

The A h o r iz o n i s a d a rk g r a y to

b l a c k loam e x te n d in g some t h i r t e e n in c h e s t o th e B h o r iz o n .

T here i s no

a c t u a l Ag h o r i z o n , b e in g r e p l a c e d by a t r a n s i t i o n a l A-^ h o r i z o n .
l a t t e r i s a v e ry d a rk loam.

The

At a d e p th o f f o u r t e e n in c h es th e B2 i s

r e a c h e d , where t h e r e i s a d e f i n i t e c l a y l a y e r .

The bottom o f th e B h o r i ­

zon i s a loamy s a n d , and a t J>6 in c h e s th e y e l l o w i s h brown sand is re a c h e d .
The l a t e r a l r o o t zone o f t u l i p p o p l a r e x ten d s to a p p ro x im a te ly f i f t e e n
in c h e s in d e p th ; t h e w a te r t a b l e i s c l o s e r to th e s u r f a c e th a n in A rea X.
E x t e r n a l d r a in a g e o r s u r f a c e r u n o f f i s s l i g h t ; i n t e r n a l d r a in a g e i s
m o d e ra te to r a p i d .
The Warsaw s o i l ty p e which i s r e p r e s e n t a t i v e o f A rea Y i s d e s ig n a te d
by V e atc h (1927) a s th e “dry" p r a i r i e r e g io n o f s o u th w e s te rn M ichigan.

A

d e s c r i p t i o n o f th e s o i l p r o f i l e h e r e p r e s e n t e d , c l o s e l y c o i n c i d e s w ith
t h a t o f V e a tc h .

A lso su ch f e a t u r e s as to p o g ra p h y , g e o lo g y , o rg a n ic m a t t e r

c o n t e n t , c l a y c o n t e n t , p r e c i p i t a t i o n , t e m p e r a t u r e , and d r a in a g e one n e a r l y
i d e n t i c a l to t h a t d e s c r i b e d by th e above a u t h o r .

With r e f e r e n c e to th e B2

65

h o r i z o n , V e a tc h p o i n t s o u t t h a t t h i s h o r i z o n becomes v e ry compact u n d e r
c e r t a i n c o n d i t i o n s , so much so t h a t i t i s r e f e r r e d to l o c a l l y a s " h a rd
pan".

The c o l l o i d a l o r c l a y c o n t e n t p r e s e n t i s s t r o n g l y c o h e s iv e o r ad­

h e s i v e and p o s s e s s e s v e ry h i g h t e n s i l e s t r e n g t h upon d r y i n g .

The s o i l

h o ld s o n ly r e l a t i v e l y s m a ll amounts o f v rater, b u t s l i g h t l y h i g h e r t h a n th e
a s s o c ia te d f o r e s te d sands.

The u p p e r p a r t o f th e s u b s tr a tu m i s d ry o r

v e r y low in m o i s t u r e and th e whole p r o f i l e i s p e n e t r a b l e to t r e e r o o t s .
Chem ical a n a l y s e s o f t h e Warsaw ty p e r e v e a l no u n u s u a l o r abnormal
p e c u l i a r i t i e s in c o m p o s itio n .

The o r g a n ic m a t t e r and n i t r o g e n c o n te n t s

a r e somewhat h i g h e r t h a n f o r com parable f o r e s t e d s o i l s and th e amounts o f
v a r i o u s i n d i v i d u a l n u t r i e n t s a r e n o t d i f f e r e n t from th o s e o f o r i g i n a l l y
f o r e s t e d s o i l s o f s i m i l a r t e x t u r e th ro u g h o u t s o u th e r n M ichigan.
fo u n d t h e
re a c tio n .

and

V eatch

h o r iz o n s s t r o n g l y to v e ry s t r o n g l y a c i d in

The most marked d i f f e r e n c e in th e p r o f i l e o f th e Warsaw and th e

p r o f i l e o f a f o r e s t e d s o i l a s s o c i a t e d w ith th e p r a i r i e , i s t h e o r g a n ic
c o n t e n t o f t h e s u r f a c e h o r i z o n s ; o th e r w is e th e y a r e s i m i l a r c h e m ic a lly and
p h y s i c a l l y and i n p r o f i l e a rra n g e m e n t.

I t a p p e a rs from o b s e r v a t i o n t h a t

t h e r e may be s l i g h t l y more com paction in th e B h o r iz o n o f t h e p r a i r i e s o i l .
I n f e r t i l i t y and p r o d u c t i v e n e s s th e d ry p r a i r i e s o i l i s c o n s id e r e d to
be i n t e r m e d i a t e , b e in g somewhat h i g h e r th a n t h e f o r e s t e d s a n d s , and l e s s
t h a n t h e f o r e s t e d more l e v e l c l a y s o i l s o f t h i s r e g i o n .

Lack o f s u f f i c i e n t

m o i s t u r e a t c r i t i c a l p e r i o d s o f th e growing sea so n i s p ro b a b ly th e c h i e f
l i m i t i n g f a c t o r in p r o d u c t i o n o f h ig h y i e l d s o f a g r i c u l t u r a l c r o p s .

In

p e d o l o g i c te r m in o lo g y , t h e Warsaw s o i l ty p e i s " m a tu re ", and s u p p o r ts a
t h e o r y t h a t th e p r a i r i e s were o r i g i n a l l y t r e e l e s s .

The p r o f i l e i n d i c a t e s

66

t h a t t h e s o i l d e v e lo p e d un der c o n d i t i o n s o f r e l a t i v e l y low m o i s t u r e ,
v a r i a b l e in t h e s u r f a c e h o r i z o n , r e l a t i v e l y low in th e B h o r i z o n , and
v e r y low in t h e 0 h o r i z o n , b e g in n in g a t d e p th s o f two to t h r e e f e e t .
A c c o rd in g t o V e atc h (1927) t h e r e i s no e v id e n c e in th e s o i l p r o f i l e o f
t h e p e c u l i a r i t i e s common to e x c e s s i v e m o is tu r e o r w a te r lo g g in g i f th e s e
c o n d itio n s ever e x is te d .

T here i s no e v id e n c e t o s u p p o rt a c o n t e n t i o n

t h a t some c h e m ic a l c o n d i t i o n in th e p r a i r i e s o i l i n h i b i t s t r e e g row th .

F ig .

11 .

SO IL 3 ANALYSIS

67

REPRESENTATIVE PROFILE AND DESCRIPTION
A rea Y - P l o t I I I

In,

F t,

2

-

4

—

6

P ro file

—

D epth

H orizon

0"-llM

Ax

11"-13”

A3

1 3 ,,- 2 4 f'

B2

D escrip tio n
Loam. Very d a r k g r a y t o
b l a c k ( 5 . 0 YR 2 . 5 / 1 . 5 ) .
Medium g r a n u l a r . pH 5 . 8 5

a—
/O

—

2

24-36

B3

Loamy s a n d t o s a n d . B ro w n t o
d a r k b ro w n ; one b a n d d a r k
b r o w n a t b o t t o m ( 6 . 5 YR 4 / 3
t o 7 . 5 YR 3 / 2 ) a t b o t t o m .
V e r y w eak n u c l f o r m t o s i n g l e
g r a i n . D a r k c o a t i n g s on
a g g r e g a t e s . G r a v e l l y . pH 5 . 1 7

CX

S a n d . Y e llo w is h brown w ith
d a r k brown i n t h i n b a n d s .
( 1 0 YR 5 / 4 t o 7 . 5 YR 3 / 2 i n
th in bands) . S ingle g ra in over
s t r a t i f i c a t i o n . No l i m e p r e s e n t
pH 5 . 4 2

3

36 - 4 6
up
4

L o a m . D a r k b r o w n ( 7 . 5 YR
3 / 1 . 7 5 ) . T r a n s i t i o n a l . pH 5 . 1 6
C lay loam t o san d y c l a y lo a m .
D a r k b r o w n ( 7 . 5 YR 3 / 2 ) .
Medium t o c o a r s e n u c l f o r m .
D a r k c o a t i n g s on a g g r e g a t e s .
G r a v e l l y • pH 5 . 0 2

S o i l T y p e - Warsaw l o a m o r s a n d y l o a m , a c i d
T o p o g r a p h y - N e a r l y l e v e l 1% t o N
v arian t
D r a i n a g e - G o o d ; W a t e r t a b l e 2-§-'
E r o s i o n - None
P e rm e a b ility - M oderately ra p id
C lassificatio n - P ra irie
L o c a tio n :

o f N-J- o f 5E-J- o f S e c 2 9 T5S R14W
C ass C o u n ty , M ic h ig a n

6s

S o i l P r o f i l e and E e l a t e d C h a r a c t e r i s t i c s
A rea Y - S t a t i o n 17
As i n t h e p r e c e d i n g s o i l t y p e , t h e p r o f i l e exposed a t S t a t i o n IY
i s r e p r e s e n t a t i v e o f th e s i t e f o r p o o r h e i g h t grow th o f t u l i p p o p l a r .
T h is p r o f i l e was made in th e a p p ro x im a te c e n t e r o f th e p l a n t a t i o n , f r e e
from any a d j o i n i n g woods.

A g ain , s u g a r maple s e e d l i n g s a r e a b s e n t ,

s u n s c a l d damage i s s e v e r e , b a s a l s p r o u t i n g o f t h e t r e e s i s p r e v a l e n t ,
and a h e rb a c e o u s g r a s s v e g e t a t i o n i s do m inant.
The p r o f i l e d e s c r i p t i o n f o llo w s much t h e same p a t t e r n a s f o r th e
Pox san dy loam .

However, t h e B ronson sandy loam, a c i d v a r i a n t , h e r e

d e s c r i b e d , i s o n ly m o d e ra te ly w e l l - d r a i n e d in c o n t r a s t to t h e w e ll to
e x c e s s i v e l y d r a i n e d Pox s e r i e s .
a t th e

A c l a y loam to sandy c l a y loam e x i s t s

h o r i z o n , g r a d in g i n t o a, loamy sand a t th e

h o rizo n .

As in

th e t h r e e s o i l ty p e s p r e s e n t , a c o a r s e sand i s found

a t a p p ro x im a te ly

31 in c h e s .

th e C]_ h o r iz o n was

At t h e tim e o f

sam p lin g o f t h i s p r o f i l e ,

c o m p le te ly s a t u r a t e d w ith w a te r .

P r a c t i c a l l y a l l o f th e w a te r f a l l i n g

on t h i s s o i l ty p e i s removed i n t e r n a l l y ; i n t e r n a l d r a in a g e i s m oderate
t o rap id, in th e u p p e r p a r t

o f th e s o i l and slow in th e low er p a r t , due

to a r e l a t i v e l y h i g h w a te r t a b l e .

Pig. 12.
69

3C IL 3 ANALYSIS

.REPRESENTATIVE PROFILE AND DESCRIPTION

A r e a Y - P l o t IV

In.

Ft •

P ro file

D epth

H orizon

Sandy lo a m . Dark r e d d i s h
b r o w n ( 6 . 0 YR 3 / 2 ) . Weak
m ed iu m g r a n u l a r . pH 5 . 3 5

2 ■
4

Ofl- 8 "

—

6 —
8 —

8 " -1 2 "

10 —

D escrip tio n

A.

1 2 " - 2 2 " B.

2 2 " - 3 1 " B3

31" -4 0 "
up

C,

Sandy lo a m . Dark brown
( 7 . 5 YR 4 / 2 ) . Weak med ium
g ra n u la r to fin e blocky.
pH 4 . 9 4
C lay loam t o sandy c l a y lo a m .
B r o w n t o d a r k b r o w n ( 7 . 5 YR
4 / 3 ) . Medium t o c o a r s e b l o c k y *
G r a v e l l y . pH 4 . 7 0
Loamy s a n d t o s a n d . D a r k
r e d d i s h b r o w n ( 5 . 0 YR 3 / 3 ) .
V ery weak c o a r s e b l o c k y .
pH 4 . 8 3
C o a rse s a n d . P a l e brown t o
d a r k r e d d i s h brown ( m o t t l e d ) .
( 1 0 YR 6 / 3 t o 6 . 0 YR 3 / 3 ) .
S a t u r a t e d w a t e r . No l i m e p r e s e n t ,
pH 5 . 8 2

S o i l Type - B r o n s o n s a n d y lo a m , a c i d v a r .
Topography - N early l e v e l
D r a i n a g e - M o d e r a t e ; W a t e r t a b l e 2-g-*
E r o s i o n - None
P e rm e a b ility * M oderately ra p id
C l a s s i f i c a t i o n - G r a y B ro w n P o d z o l i c
L o c a tio n :

Eg- o f N-J o f S E j o f S e c 2 9 T5S KL4W
C ass C ou n ty, M ic h ig a n

70

2 . S p e c i f i c G r a v i t y o r R eal D e n s ity
E x p e r im e n ta l Method:
The s p e c i f i c g r a v i t y was d e te rm in e d on t h i r t y - t w o sam ples in
d u p l i c a t e r e p r e s e n t i n g th e A-|_ and A2 h o r iz o n s f o r each o f f o u r sam pling
s t a t i o n s , a c c o r d in g t o th e t e c h n i q u e o f L utz (1 9 4 4 ).

S o i l s from t h e f i e l d

were a i r - d r i e d and p a s s e d th ro u g h a two mm. s i e v e ; t h e s e sam ples were th e n
p l a c e d in a p ic n o m e te r w ith f r e s h l y b o i l e d d i s t i l l e d w a te r .

By r e p e a t e d

e v a c u a t i o n i n a vacuum d e s i c c a t o r th e i n t e r s t i t i a l a i r was g r a d u a l l y r e ­
p l a c e d by w a te r .

A f t e r a l l th e a i r had been removed from t h e s o i l ,

a p p r o p r i a t e te m p e r a t u r e s and tim e were r e c o r d e d end th e s p e c i f i c g r a v i t y
d e te r m in e d by d i v i d i n g th e w eigh t o f th e o v e n -d ry sample by t h e volume of
so il.

A summation o f t h e v a lu e s o b ta in e d f o r two h o r iz o n s i s p r e s e n t e d in

T a b le 6 .
TABLE 6 .
SPECIFIC GRAVITY OF THE "A" HORIZON OF SOILS IN AREA X AND AREA Y
Area, X ( S t a t i o n s I - I I )
H orizon

IIA i

IIA 2

Oven-dry VJeight (gins.)

Volume of S o i l (ml)

17-42
20.50

6.77

19*5^
21. S6

7. 62
S . 42

S . 12

S p e c i f i c G ra v ity
2.60
2.52

Area Y (S ta tio n s III-IV )

7.37

ih a 2

21.02
i 7. l l

6.23

2.39
2 .7 4

IVA-i
iv a 2

19.23
17.85

6.35
6.73

2 .S 4
2. 7b

IIIA -l

71

D is c u s s io n o f R e su lts
The s p e c i f i c g r a v it y , or r e a l d e n s ity o f a s o i l is u n a ffe c te d by
s t r u c t u r e , and thus the s p e c i f i c g r a v ity d i f f e r s from th e volume w eight
of s o ils .

Wide v a r ia t io n in m in eral s o i l s does not e x is t as shown by the

p r e ce d in g d a ta .

The average s p e c i f i c g r a v ity fo r Area X, which in c lu d e s

both th e A-^ and Ag h o r iz o n s , is 2 .$ 8 ; th e s p e c i f i c g r a v ity fo r Area Y o f
the same h o r iz o n s i s 2 .6 4 .

These v a lu e s r ep re sen t on ly a d if fe r e n c e o f

.06 betw een the two a r e a s , and o b v io u sly i s i n s ig n if ic a n t even though
th er e are th re e in d iv id u a l s o i l ty p es r ep r e se n te d .

The v a lu e s o b tain ed

in Table 5 are used in th e form ula fo r computing th e t o t a l p o r o s ity .
To determ ine th e s t a t i s t i c a l d iffe r e n c e in s p e c i f i c g r a v ity o f the
s o i l s fo r th e area o f good and poor h e ig h t growth o f t u lip p o p la r, an
a n a ly s is o f v a ria n ce fo llo w s in Table 7*

N eith er th e A^ nor th e A2

h o rizo n shows any s t a t i s t i c a l s ig n if ic a n c e .
TABLE 7 .
ANALYSIS OF VARIANCE FOR SPECIFIC GRAVITY AREA X v s . AREA Y
B a s is : 32 samples
Hor izo n
Ax

A2

Source

D egrees o f Freedom

T otal
X vs Y
Error

15
1
l4

T otal
X vs

Error

15
Y

Sum o f Squares
.27
.02
.23

Mean Square

F

.02
.018

1 .1

.4-1

1

.0 1

.0 1

l4

.40

.028

.36

72

3* Volume Weight o r A p p aren t D e n s ity
E x p e rim e n ta l Method;
The volume w e igh t was d e te rm in e d on t h i r t y - t w o f i e l d samples
t a k e n i n s i t u hy u s e o f a s o i l c o r e sam pler a c c o rd in g to B aver ( l 9 4 g ) .
Core sam ples were ta k e n from th e

and A2 h o r iz o n s in each a r e a .

A fte r

d e te r m in in g th e w e ig h t o f each c o re a t f i e l d c a p a c i t y , a d i s k o f f i l t e r
p a p e r and c h e e s e c l o t h was f i r m l y a t t a c h e d t o one end o f th e c o r e .

By means

o f an o v e r f lo w cup t h e volume o f s o i l and c y l i n d e r were o b t a i n e d .

The

f i l l e d c o r e s were p l a c e d in a pan o f w a te r and a llo w e d to s a t u r a t e f o r 24
hours.

F o r t h e s e u n d i s t u r b e d c o r e s , o v e n -d ry w e ig h ts were c a l c u l a t e d as a

f i n a l s t e p i n th e p r o c e d u r e and from th e above te c h n iq u e th e volume w eight
was d e te r m in e d by d i v i d i n g th e o v e n -d ry w eig ht o f each samole by t h e volume
of s o i l .

T h is method d i f f e r s e s s e n t i a l l y from th e s p e c i f i c g r a v i t y
TABLE S.

VOLUME WEIGHT OP THE "A" HORIZON OP SOILS IN AREA X AHD AREA T
A rea X ( S t a t i o n s I - I I )
H o riz o n

O ven-dry Weight (gm s.)

453-15
11^
IIA g

Volume o f S o i l (m l.)

344.25

Volume Weight

5 9 9 -l 4

371.00

1 .31
l.b O

509.S3
606.29

359-00
3 74.00

1 .4 l
1 .6 2

Area Y ( S ta tio n s III-IV )
11IAI iia "

4 9 1 .7 7
5 3 3.2 2

367.50
364.00

IVA-,
iv a 2

4 g g .l0
633.17

363.25
375.75

73

d e t e r m i n a t i o n in th e f a c t t h a t th e in c lu d e d p o re space i s m easu red , th u s
g i v i n g lo w e r v a l u e s th a n f o r s p e c i f i c g r a v i t y .

The volume w eight e x p r e s s e s

t h e r a t i o "between t h e d ry w e ig h t o f a g iv e n volume o f u n d i s t u r b e d s o i l and
t h e w e ig h t o f an e q u a l volume o f w a te r .

The v a lu e s o b ta in e d in T ab le &

r e p r e s e n t t h e number of tim e s a p a r t i c u l a r sample i s h e a v i e r th a n an e q u al
volume o f w a te r .
D is c u s s i o n o f R e s u l t s
S in c e t h e volume w eig ht d e t e r m i n a t i o n in c lu d e s th e a i r sp ace i t i s
e v i d e n t from t h e above c a l c u l a t i o n s t h a t in e v ery c a s e th e A]_ h o r iz o n shows
s m a l l e r v a l u e s th a n th e Ag, an i n d i c a t i o n o f th e g r e a t e r a i r c a p a c i t y in t h e
topm ost h o r i z o n .

The a v e ra g e volume w eight f o r Area. X i s 1 .^ 9 aud f o r

A rea T i t i s 1 . ^ 2 .

A s l i g h t d i f f e r e n c e o f .07 i s r e c o g n i z a b l e in t h e two

a r e a s , d e s p i t e t h e f a c t t h a t loam s o i l s a r e e v id e n t in A rea Y.
TABLE 9 .
ANALYSIS OF VARIANCE 3T0R VOLUME WEIGHT AREA X v s . AREA Y
B a s i s : l 6 sam ples
H o riz o n

Source

D egrees o f Freedom

A1

T otal
X vs Y
E rror

15
1
lb

.03
.00
.03

. 00
. 00 2

.00

T o tal
X vs Y
E rror

15
1
lb

.2b
. 05
.19

.05
.013

3 .sU

A2

Sum of Squares

Mean Square

F

I n o r d e r to f u r t h e r check th e s t a t i s t i c a l s i g n i f i c a n c e o f th e two a r e a s
u n der c o n s i d e r a t i o n , an a n a l y s i s o f v a r i a n c e was made to d e te rm in e th e
m agnitude o f d i f f e r e n c e s .

No s i g n i f i c a n t d i f f e r e n c e s in e i t h e r t h e Ap o r A2

h o r i z o n were a p p a r e n t f o r volume w e ig h t.

74

A c c o rd in g t o L u tz and C hand ler (19^6) th e volume w eigh t o f th e Ap
h o r i z o n o f f o r e s t s o i l s is commonly l e s s th a n 1 .0 0 .

T his v a lu e i s con­

s i d e r a b l y lo w e r t h a n th e v a l u e s o b t a i n e d and i s in a c c o rd v i t h th e f a c t
t h a t t h e s o i l s b e in g i n v e s t i g a t e d a r e n o t s t r i c t l y " m a tu re ” f o r e s t s o i l s ,
and a r e l e s s p o ro u s t h a n f o r e s t s o i l s i n s o f a r as th e volume w eight is
c o n c e rn e d .

The h ig h volume w e ig h ts o b ta in e d a r e an i n d i c a t i o n o f th e

s t r u c t u r e o f th e s e s o i l s s i n c e th e low p o re volume i n d i c a t e s h ig h e r
volume w e ig h ts .

A lso t h e h ig h volume w e ig h ts i n d i c a t e in a g e n e r a l way

t h e low o r g a n ic m a t t e r as w e ll as th e h ig h c o n te n t of sand in t h e s e s o i l s .
P o re Volume ( T o t a l , C a p i l l a r y , and N o n - c a p i lla r y )
E x p e rim e n ta l Method:
The p o r e volume was d e te rm in e d on t h i r t y - t w o d u p l i c a t e f i e l d
sam ples t a k e n in s i t u by u se o f a s o i l c o re s am p ler.

These sam ples were

ta k e n from t h e A]_ and Ag h o r iz o n s f o r A rea X and A rea Y.

A fte r d e te r­

m ining t h e s a t u r a t e d w eigh t o f each c o r e , th e c y l i n d e r s were p l a c e d on
a pE t a b l e a t a s o i l pE of 1 . 6 f o r tw e n ty - f o u r h o u rs .

The c o r e s were

w eighed a f t e r d r a i n i n g on th e pE t a b l e and th e n o v e n - d r ie d a c c o rd in g to
B aver (l9*+g) .

From t h e s e d e t e r m i n a t i o n s th e p e r c e n t t o t a l p o r o s i t y , non­

c a p i l l a r y p o r o s i t y , and c a p i l l a r y p o r o s i t y were c a l c u l a t e d .

T o tal p o ro s ity

was o b t a i n e d by d i v i d i n g t h e s p e c i f i c g r a v i t y minus th e volume w eight by
th e s p e c i f i c g r a v i t y and m u l t i p l i e d by 100.

To g e t th e p e r c e n t c a p i l l a r y

p o r o s i t y , s u b t r a c t t h e t o t a l p o r o s i t y minus th e n o n - c a p i l l a r y p o r o s i t y .
A summation of p o r e volume v a lu e s i s g iv e n in T able 10.

75
TABLE 1 0 .

PORE VOLUME OP THE "An HORIZON OP SOILS IN AREA X AND AREA Y
P ercent p o ro s ity
A re a X ( S t a t i o n s I - I l )
H o riz o n

C ap illary

H o n -c ap illary

T o tal P o ro sity

IA i
ia 2

2 4.9
21.0

25.2
16.3

50.1
3 7 .3

IIA X
iia 2

25.9
26.4

17-5
1 1.7

4 3 .4
38.1

A rea Y ( S t a t i o n s I I I - I V )
I I IA i
IIIA 2

26.0
29.1

21.5
15.3

4 7 .8
4 4 .4

IVAp
IVA2

2 8 .0
2 6 .7

22.2
1 3 .8

50.2
4 0 .8

A verage V alues Combined S t a t i o n s
I-IIA i
i-iia 2

25.4
25+.1

2 1 .3
13.6

4 6 .8
37. s

I 1 I-IV A !
iii-iv a 2

27.0
2 7 .9

21. 5
1 4 .6

4 8.9
4 2 .5

I —I I AtAp
I I I - I V a xa 2

2 4 .g
2 7 .5

1 7 .4
IS . 2

4 2 .8
4 5 .7

D is c u s s i o n o f R e s u l t s
The r e l a t i v e p r o p o r t i o n s o f a i r and w a te r in a s o i l w i l l c o n s t a n t l y
ch an ge.

I t i s c o n v e n ie n t to employ th e c o n cep t o f l a r g e and s m a ll p o re s

which d e te r m in e t o a g r e a t e x t e n t th e a e r a t i o n and i n t e r n a l d r a in a g e o f
th e s o i l .

The above v a lu e s a r e b e s t e v a lu a te d by a v e ra g e s o f th e comb­

in e d s t a t i o n s in d u p l i c a t e f o r th e t h r e e main c l a s s e s o f p o re volume.

The

v a l u e s o b t a i n e d in Ta.ble 10 i n d i c a t e t h a t t h e r e i s g r e a t e r n o n - c a p i l l a r y ,
c a p i l l a r y , and t o t a l p o re space in A rea Y th a n in Area X.

T h is i s t r u e f o r

b o th t h e Ax and A2 h o r iz o n s in e v ery c a s e , and c o r r o b o r a t e s th e volume

76

w e ig h t d e t e r m i n a t i o n s .
g re a t.

However, th e m agnitude o f t h e d i f f e r e n c e s i s n ot

The r e la /b iv e p r o p o r t i o n o f c a p i l l a r y to n o n - c a p i l l a r y p o re space

i s more marked in th e A2 h o r iz o n th a n in th e
A re a Y.

h o r iz o n in d o th A rea X and

An a n a l y s i s o f v a r i a n c e (T a b le 11) i n d i c a t e s no s i g n i f i c a n t

d i f f e r e n c e in p o r e volume o f any c l a s s i f i c a t ion by comparing th e v a lu e s
o f A re a X and Area, Y.
TABLE 11.
ANALYSIS OP VARIANCE OP PORE VOLUME POR SOILS OP THE "A" HORIZON IN AREA X
v s . AREA Y
B a s i s : l 6 sam ples
P ercent c a p il la r y p o ro s ity
H orizon

Source

D egrees o f Preedom

A1

T o tal
X vs Y
E rror

15
1
lb

58.05
10.^9
1+7-66

IO .39
3 . bo

3 .0 5

T o tal
X vs Y
E rror

15
l
l^l-

1+18.59
5 6 .6 3
361.96

56.63
25.35

2.19

a2

Ai

a2

T otal
X vs Y
E rror
T o tal
X vs Y
E rror

Sum o f Squares

Mean Sq.ua.re

P ercen t N o n -c ap illary P o ro s ity
292 .29
15
.96
l
lb
291.33
15
l
i^

30 3. 23
3*70
299.53

P

.96
20.80

. 0 l+

3*70
21.39

*17

P ercen t T otal P o ro sity
A-ij.

A2

T o tal
X vs Y
E rror

15
1
ib

291. ^
1 7 . 61+
2 7 3 . go

1 7 .6 4
19.55

.90

T otal
X vs Y
E rror

15
l
i^

5 U2 .0 0
S9 . 3 0
U5 2 . 7 0

39.30
3 2 . 3O

2.76

77

B av e r (19^-0) p o i n t s o u t t h a t th e t o t a l p o r o s i t y o f s o i l s i s
u s u a l l y i n t h e neighborhood, o f f i f t y p e rc e n t*

The a v e ra g e v a lu e s ob­

t a i n e d in a l l sam ples h e r e investiga/fced ra n g e s from a low o f 37*3 Per_
c e n t t o a h ig h o f 50 -2 p e r c e n t t o t a l p o r o s i t y .
from t h e A]_ to th e

P o re volume d e c r e a s e d

h o r iz o n f o r a l l c l a s s e s o f p o r o s i t y in b o th a r e a s .

I n A re a X t h e c a p i l l a r y p o re sp a c e i s 7*^ p e r c e n t g r e a t e r th a n th e non­
c a p i l l a r y p o r e s p a c e ; A rea Y has a s i m i l a r s i t u a t i o n w ith a 9*3 p e r c e n t
g r e a t e r c a p i l l a r y p ore space.

The n a t u r e o r k in d o f p o re space w i l l

d e te r m in e t h e f i e l d c a p a c i t y , i n t e r n a l d r a i n a g e , and amount o f a e r a t i o n .
The a i r c a p a c i t y o f s o i l s i s o f t e n c o n s id e r e d as b e in g e q u i v a l e n t to th e
n o n - c a p i l l a r y p o r e volume.

C a p i l l a r y p o re volume may be e x p r e s s e d as

e q u iv a le n t to th e f i e l d c a p a c ity .

The n a t u r e o f th e n o n - c a p i l l a r y p o re s

i s f a c i l i t a t e d by m easurem ents o f t h e r a t e o f i n f i l t r a t i o n o f w a te r .

A

l a r g e number o f in te r-c o m m u n ic a tin g n o n - c a p i l l a r y p o r e s u s u a l l y means
h ig h i n f i l t r a t i o n r a t e s .

The a i r c a p a c i t y i s a l s o r e l a t e d to s o i l

te x tu re .
5* H y g ro sco p ic C o e f f i c i e n t
E x p e rim e n ta l Method:
To d e te r m in e t h e h y g r o s c o p ic c o e f f i c i e n t , as o u t l i n e d by Baver
( 191+g) , tw e n ty f i e l d sam ples were ta k e n a t f i v e s o i l h o r iz o n s in A rea X
and A re a Y.

The sam ples were a i r - d r i e d and f i v e grams o f each was p l a c e d

in w eighed w eig h in g c a n s .

The u n c o v ered cans were p l a c e d in an oven a t

105° C f o r tw e n t y - f o u r h o u r s , w eighed, and th e h y g ro s c o p ic c o e f f i c i e n t
d e te r m in e d .

An in d e x o f th e s u r f a c e a c t i v i t y o f s o i l s is th u s o b t a i n e d ,

o r t h e amount o f w a te r a d so rb e d on th e s u r f a c e of s o i l p a r t i c l e s in an

18

a tm o s p h e re o f w a te r v a p o r o f known, r e l a t i v e h u m id ity .

The c o e f f i c i e n t s

o b t a i n e d a r e s u p p o se d t o mark th e u p p e r l i m i t o f th e h y g ro s c o p ic m o is tu r e
r a n g e a t a p p r o x im a te ly a, pF of 4 . 5 .

A summation o f r e s u l t s i s g iv e n in

T a b le 12.
TABLE 12.
HYGROSCOPIC COEFFICIENT VALUES FOR FIVE SOIL HORIZONS AREA X AND Y
P ercent
A rea X ( S t a t i o n s I - I I )
H o riz o n
IA-i
A-2
b2
b3
Cl
IIA-i
a2
b2
B3
*1

Weight o v e n -d ry s o i l

Weight w a te r l o s t

H y groscop ic C o e f f i c i e n t

6 .U7
5 .5 6
5-51
5 .9 1
5*59

.03
.025
.055
.01
.005

.46
.45
• 998
*17
.09

4 .6 7
5*55
4 .9 5
5*78
^*77

.02
.03
.03
.015
.01

.5 4
.61
.2 6
.21

A rea Y ( S t a t i o n s I I I - I V )
I IIA-i
a3
B2
ici
IVA-iX
ACL
p
b2
B3
o3
i

4 .7 5
5*70
6.09
6.06
5*91

.04
.06
*075
.005
.005

.84
1.05
1.23
.08
.084

5*07
4.94
4.65
5*9 8
5 . 3^

.025
.0 4
.03
.02
.003

*49
.81
.64
*33
.09

D is c u s s i o n o f R e s u l t s
I n s p i t e o f th e u n s a t i s f a c t o r y n a t u r e o f h y g ro s c o p ic m o is tu r e v a l u e s ,
P u r i (1925) and Keen (1 9 3 1 ), t h i s c o n s t a n t has found wide u s e .

In th e

79

p r e s e n t i n v e s t i g a t i o n , t h e v a lu e s o b t a i n e d f o r th e Ag and B2 h o r iz o n s o f
A re a Y a r e h i g h e r t h a n th o s e in A rea X.

I n g e n e r a l , th e h i g h e s t v a lu e s o f

h y g r o s c o p ic c o e f f i c i e n t a r e fo u nd in s o i l s h a v in g a h ig h c o n t e n t o f c o l l o i d s .
The r e l a t i o n s h i p betw een th e m e c h a n ic a l a n a l y s i s and th e h y g ro s c o p ic co­
e f f i c i e n t i s d e f i n i t e l y b ro u g h t o u t h e r e as e v id e n c e d by th e h i g h e r v a lu e s
o f A re a Y ( S t a t i o n I I I ) *
h o r i z o n s f o r A re a Y.

In g e n e r a l , h ig h e r v a lu e s a r e fo u nd in a l l

A s t a t i s t i c a l a n a l y s i s (T a b le 13 ) I n d i c a t e s no s i g ­

n ific a n t d iffe re n c e s.
TABLE 13.
ANALYSIS OP VARIANCE OP HYGROSCOPIC COEFFICIENT FOR FIVE SOIL HORIZONS AREA X
(GOOD HEIGHT GROWTH) v s . AREA Y (POOR HEIGHT GROWTH)
B a s i s : 25 sam ples
H o riz o n
A1

A2

cL

Bv
j

J.

Source

D egrees o f Freedom

Sum o f Squares

T o tal
X vs Y
E rror

3
1
2

.110
.050
.060

.050
.030

T o tal
X vs Y
E rror

3
1
2

.22 27
.1898
.0329

.1898
.0164

T o tal
X vs Y
E rror

3
1
2

.245
.014
.231

.014
• 115

.012

T otal
X vs Y
E rror

3
1
2

.035^
.0001
.0333

.0001
.0176

.005

T o tal
X vs Y
E rror

3
1
2

.0115
.0042
.0073

.0042
.OO36

Mean Square

F

1.67

15.73

1 .1 7

80

6.

Maximum W ate r-H o ld in g C a p a c ity
S x p e r im e n ta l Method:
I n o r d e r to d e te rm in e th e maximum w a te r - h o ld in g c a p a c i t y o f

th e t h r e e s o i l ty p e s u n d e r i n v e s t i g a t i o n , s i x t y - f o u r sam ples were
c o l l e c t e d from th e p r o f i l e s r e p r e s e n t i n g f i v e h o r iz o n s in A rea X and
A rea Y.

These sam ples were a i r - d r i e d and p a s s e d th ro u g h a two mm. siev e*

A t h i r t y gram sample was th e n p l a c e d in s q u a re m o is tu r e e q u i v a l e n t boxes
and f i l t e r p a p e r p l a n e d in th e bo tto m o f th e box.

The c o n t a i n e r s were

p l a c e d in a one cm. l a y e r o f w a te r and a llo w e d to s a t u r a t e f o r tw e n ty f o u r h o u r s , a f t e r which tim e th e y were d r a in e d f o r t h i r t y m in u te s ,
w eigh ed, and t h e p e r c e n t a g e m o is tu r e d e te rm in e d a t th e maximum w a te r h o ld in g c a p a c i t y , as o u t l i n e d by B aver (1 9 ^ 8 ).
As a c o m p ariso n betw een u s in g a i r - d r y samples and s o i l s i n t h e i r
n a t u r a l c o n d i t i o n , t h i r t y - t w o more sam ples were c o l l e c t e d in s i t u by
means o f a c o re sam p ler a c c o rd in g to th e o r i g i n a l method o f Schumacher
(1 S 6 4 ).

The same p ro c e d u re was c a r r i e d o u t on th e c o re sam p les, and th e

w a t e r - h o l d i n g c a p a c i t y d e te rm in e d on s o i l s o f th e same a re a b u t in t h e i r
u n d istu rb e d c o n d itio n .

This com parison o f methods was deemed a d v i s a b l e

s i n c e v a r i o u s i n v e s t i g a t o r s have s h o rn v id e d i f f e r e n c e s in th e two m ethods.
By a i r - d r y i n g and s i e v i n g a sample, th e n o n - c a p i l l a r y , in te rc o m m u n ic a tin g
p o re s p a c e and n a t u r a l s t r u c t u r e o f th e s o i l i s a l t e r e d .
reasons,

For th ese

i t i s p r e f e r a b l e to c o l l e c t s o i l s in s i t u f o r w a te r - h o ld in g

c a p a c ity d e te rm in a tio n s.

The n a t u r a l c o r e s were ta k e n from a l l h o riz o n s

w ith th e e x c e p t i o n o f th e C^.

A condensed summary of th e v a l u e s f o r a i r -

d ry and n a t u r a l c o r e s , i n c lu d in g p e r c e n ta g e d i f f e r e n c e s f o r th e "A" and
“B 11 h o r i z o n s in th e two m ethods, is g iv e n in T ab le l b .

21

TABLE l 4 .

MAXIMUM WATER-HOLDING- CAPACITY OP SOILS REPRE3ENT IIIG- PIYE SOIL HORIZONS
IN AREA X AND AREA Y
P e r c e n t M o istu re
A rea X ( S t a t i o n s I - I I )
S o i l H o riz o n

W a te r- h o ld in g C a p a c ity
( A i r - d r i e d and s ie v e d )

IA X

Ap

%
B2

IIA p

A£
B2

W a te r-h o ld in g C a p a c ity
( N a tu r a l c o n d itio n )

Avg. D i f f e r e n c e
A ir-d ry vs.
N a tu r a l

52.1
4 6 .9
4 4 .3
22.3
22.5

4 2 .5
26.3
23.3
22.7
—

15.6
20.6
21.0
5 .6
—

5 6 .9
4 4 .4
3 9 .3
3 1 .3
2 9.5

3 5 .2
2 4 .2
25.9
23 .3

2 1.7
20.2
1 3 .4
2.0

A rea Y ( S t a t i o n s I I I - I V )
IIIA-i
A,

4

B3
CI
IVAx
Ao

Boc.
C31

5 9 .6
63.6
5 2 .5
30.1
22.0

22.9
3 2 .7
27.6
20.9

5 7 .4
37.3
4 6 .7
36.0
29.0

3 2.9
29.2
25.5
24.5
—

—

20.7
30-9
2 4 .9
9 .2
—
20.5
22.1
21.2
11.5
—

D is c u s s i o n o f R e s u l t s
S in c e t h e c o n t i n u i t y o f w a te r su p p ly f o r f o r e s t t r e e s i s f u l l y as
im p o r ta n t as th e t o t a l amount, a measure o f th e w a te r—h o ld in g r e t e n t i o n of
i n d i v i d u a l s o i l h o r iz o n s is v e ry im p o r ta n t.

The w a te r r e t a i n e d in s o i l s

a f t e r g r a v i t a t i o n a l w a te r has d r a in e d o f f , or th e c a p i l l a r y and h y g ro s c o p ic
w a te r , may “become c r i t i c a l f o r c e r ta .in s p e c i e s of t r e e s .

T h is i s espe­

c i a l l y t r u e where th e s o i l s a r e s u b j e c t to h ig h e v a p o r a tio n and su b se q u e n t

S2

d r y in g o u t a t c e r t a i n p e r i o d s o f th e grow ing s e a s o n .

T ree s grow ing in

s o i l s o f low f e r t i l i t y r e q u i r e l a r g e r amounts of w a te r th a n t r e e s g ro wing
in f e r t i l e s o i l s , b a s e d upon th e w a te r re q u ire m e n t f o r e ach u n i t o f d ry
m a t t e r p ro d u c e d .

I n humid r e g i o n s , c o a r s e sandy s o i l s h a v in g deep w a te r

t a b l e s a r e o f t e n p o o r e r s i t e s th a n s o i l s o f medium o r f i n e t e x t u r e .

In

a c o n s i d e r a t i o n o f s o i l - m o i s t u r e r e l a t i o n s h i p s one must alw ays c o n s id e r
t h e n a t u r e o f t h e d e e p e r s o i l h o r iz o n s and u n d e r ly in g s t r a t a , s in c e th e
low er h o r i z o n s o f t e n d e te r m in e th e r e p le n is h m e n t of w a te r a t c r i t i c a l
p e rio d s.

P e a r s o n and Marsh (1935) have p o i n t e d out t h a t l a y e r s o f f i n e -

t e x t u r e d m a t e r i a l l y i n g s e v e r a l f e e t below th e s o i l surfa,ce may be h ig h ly
im p o r ta n t in t r e e g ro w th .

The w a t e r - h o l d i n g v a lu e s o b ta in e d in t h i s

i n v e s t i g a t i o n show a d e f i n i t e r e l a t i o n s h i p to s o i l t e x t u r e and to th e
d e p th o f t h e u n d e r l y i n g w a te r t a b l e .

An a n a l y s i s of v a r i a n c e o f th e

w a t e r - h o l d i n g c a p a c i t y by h o r iz o n s shows a d e f i n i t e s i g n i f i c a n c e in th e
h o r iz o n o f s i r - d r y and n a t u r a l c o r e s , when A rea X and A rea Y a r e
com pared.

No s t a t i s t i c a l s i g n i f i c a n c e i s found betw een S t a t i o n s I and I I

o r b e tw e e n S t a t i o n s I I I and IV f o r th e A^ h o r i z o n , b u t a marked d i f f e r e n c e
i s fo u n d betw een combined A rea X and A rea Y.

T h is a n a l y s i s s u b s t a n t i a t e s

th e f i n d i n g s o f th e t e x t u r a l c l a s s i f i c a t i o n (m e c h an ic a l a n a l y s i s ) .

The

s t a t i s t i c a l a n a l y s i s i s p r e s e n t e d in T able 15*

7.

M o is tu r e E q u i v a le n t
Experimental Method:
M o is tu r e e q u i v a l e n t d e t e r m i n a t i o n s were made on tw enty f i e l d

sam ples r e p r e s e n t i n g f i v e h o r iz o n s f o r A rea X and f i v e h o riz o n s f o r A rea Y.
The method o f B rig g s and S han tz (1912) was u t i l i z e d in a l l d e t e r m i n a t i o n s ,

TABLE 1 5 .

ANALYSIS OF VARIANCE OF THE MAXIMUM WATER-HOLDING CAPACITY FOR AIR DRY
AND NATURAL SOIL CORES IN AREA X v s . AREA Y

A i r - d r i e d and s i e v e d sam ples
B a s i s : 32 sam ples
H o riz o n
A1

“^2

b2

j

°1

S ource

D egrees o f Freedom

Sum o f Squares

Mean Square

F

*+.2
6.58

.6*4

T o tal
X vs Y
E rror

15
1
1*4-

96. b
b .z
92.2

T o tal
X vs Y
E rror

15
1
1*4

13 ^ 5 . 0
85 U.0
1+9 1 . 0
B a s i s : *+ samples

T o tal
X vs Y
E rro r

3
1
2

90.16
6 0 . %b
29.32

6 0 .S*+
1*4.66

*+.15

T o tal
X vs Y
E rror

3
1
2

32.^7
10.56
21.91

10.56
10.95

.96

T o tal
X vs Y
E rror

3

1.25
.25
1.00

.25
.50

.005

.0 2
16.66

.001

1

2

85*+.0
35 .07

2U.14**

N a tu r a l Core Samples
B a s i s : l 6 samples
Ai

Ao
c.

A pC-

CL

T o tal
X vs Y
E rror

15
1
i*+

T o tal
X vs Y
E rror

15
1
ib

T o tal
S u b sta tio n s
L o c a tio n
E rror

15
6
1

T o tal
S u b sta tio n s
L o c a t ion
E rror

15
6
1
g

233.51
.02
233-^9
*+71*37
1 30.37
3^ 1 . 0 0
Combined S t a t i o n s I - I I

130.37
2 *+.35

5 . 35*

g*+0 . IS
283-55
25.00
s
531.^3
Combined S t a t i o n s I I I - I V

*47.26
25.00
66,*45

. 3s

79.51
I 5 6 . 2U
59.90

2 .b l

** S i g n i f i c a n t a t 1$ and 5^
* S i g n i f i c a n t a t ^f0

1 1 1 2 . 5 *+
*177.08
1 5 6 . 2 *+
*+79.22

sk

with, a p p r o p r i a t e m o d i f i c a t i o n where n e ed e d .

T h i r t y grams o f a i r —d ry s o i l ,

p r e v i o u s l y p a s s e d th ro u g h a two mm. s i e v e , was pla.ced in th e "bottom o f
s c r e e n e d m o is tu r e e q u i v a l e n t b o x e s .

These "boxes were th e n p la c e d in a

one cm. l a y e r o f w a te r and a llo w e d to s a t u r a t e f o r tw e n ty - f o u r h o u rs .
A f t e r d r a i n i n g f o r t h i r t y m in u te s th e boxes were p l a c e d in a c e n t r i f u g e
f o r t h i r t y m in u te s a t a speed o f 2 UhO r e v o l u t i o n s p e r m in u te , e q u i v a l e n t
to 1000 tim e s th e f o r c e o f g r a v i t y .

The boxes were th e n weighed and

sam ples o v e n - d r i e d ; th e m o is tu r e e q u i v a l e n t was th e n c a l c u l a t e d from th e
above r e s u l t s .

A summation of th e v a l u e s o b ta in e d by h o r iz o n i s g iv e n

i n T a b le l 6 .
D is c u s s i o n o f R e s u l t s
The m o is tu r e e q u i v a l e n t i s one o f th e most f r e q u e n t l y u se d c o n s t a n t s
f o r e x p r e s s i n g th e m o is tu r e r e l a t i o n s o f s o i l s .

In c e n t r i f u g i n g th e

s a m p le s , th e f o r c e i s c o n s id e r e d to remove th e w a te r h e ld in th e l a r g e r
p o re s *

I n t h i s i n v e s t i g a t i o n th e m o is tu r e e q u i v a l e n t i s u t i l i z e d to

express s o i l te x tu r e .

A ccording to Yeihmeyer and H e nd rick so n (1931) i t

g i v e s a f a i r l y r e l i a b l e measure o f th e f i e l d c a p a c i t y of f i n e - t e x t u r e d
so il.

The v a lu e s would no doubt be h ig h e r in t h i s s tu d y when u s in g th e

m o is tu r e e q u i v a l e n t as a measure of th e f i e l d c a p a c i t y , s i n c e th e s o i l s
s tu d ie d are of a coarse te x tu re .

The v a lu e s of T able 1 6 show a f a i r l y

c l o s e c o r r e l a t i o n w ith th e v a lu e s o b ta in e d f o r th e m e ch a n ic al a n a l y s i s .
G r e a t e s t d i f f e r e n c e s o c c u r in t h e

and

h o r i z o n s , and th e h i g h e s t

v a lu e s o c c u r in A rea Y a t S t a t i o n I I I , where th e s o i l tyoe a p p ro ach es a
loam to c l a y loam.

From t h e s e r e s u l t s i t is e x p e c te d t h a t th e s o i l s of

A rea Y would r e a c h f i e l d c a p a c i t y so o n er th a n th e s o i l s of A rea X.
M oisture e q u iv a le n t v a lu e s in c r e a s e v i t h in c r e a s e in c o l l o i d a l content

25
TABLE 16.
MOISTURE EQUIVALENT VALUES FOR FIVE SOIL HORIZONS AREA X AND AREA I
P ercent
A rea X ( S t a t i o n s I - I I )
H o riz o n
IA i
A2
Bg

B3

ci

IIA j.

A2
b2

°x

¥ t . o v e n -d ry (gm s.)

Wt. w a te r l o s t (gm s.)

M o istu re E q u iv a le n t

29 .55
29.66
3 0 .0 3
2 9 .4 1
3 7-27

1 .99
1 .3 9
1.70
.23
.09

6.73
4 .7 0
5.66
.78
.25

3 0 .8 5
2 9.37
29.60
3 1 .0 4
27-89

2 .1 4
1 .4 4
1 .7 4
.70
.03

6.93
4.90
5 .S 6
2.25
.23

A rea Y ( S t a t i o n s I I I - I Y )
IIIA- l
A2
b2
B3

Cl

IVA-i
a 2CL
B2
B7
Cl

2 9.2 6
3 0 .5 7
30.61
30.32
2 3.7 1

2 .23
3.49
3 .2 3
.23
.15

10.73
.74
.54

2 9 .0 4
2 0 .03
23.21
2 9.31
2 3 .5 6

2 .0 3
1 .3 4
1.86
•39
.03

6.99
6.67
6 . 6s
1.31
.23

7.79

n.4o

as “b orn e o u t by com pering th e c l a y c o n te n t of th e above t h r e e s o i l t y p e s .
An a n a l y s i s o f v a r i a n c e (T a b le 17) shows no s i g n i f i c a n t s t a t i s t i c a l
d i f f e r e n c e betw een th e m o is tu r e e q u i v a l e n t s of A rea X and A rea Y,
g.

S o i l M o is tu r e E v a p o r a tion

(Ground Cover Absent)

E x p e rim e n ta l Method:
S o i l c o re s in s i t u were ta k en a t f i v e d i s t i n c t s o i l h o riz o n s
r e p r e s e n t i n g tw e n ty i n d i v i d u a l c o re s from A rea X and Area Y.

The samples

were s a t u r a t e d in a two cm. l a y e r of w a te r f o r tw e n ty - f o u r h ou rs and th e n

s6
TABLE 1 7 .

ANALYSIS OF VARIANCE 01 MOISTURE EQUIVALENT FOR AREA X v s . AREA Y
P e r c e n t M o istu re
B a s i s ! 20 samples
H o riz o n
A1

Ag

b2

D

Cl

w eig h ed.

Source

D egrees of Freedom

T o tal
X vs Y
E rror

3
1
2

T oted
X vs Y
E rror

Sum o f Squares

Mean Square

F

.65
.31
*3^

•31
.17

1.00

3
1
2

29 .14
17.93
11.21

17.93
5.60

3.21

Tot ad
X vs Y
E rror

3
1
2

16. ss
s . 67
S . 21

g .67
4 .1 0

2.11

T o tal
X vs Y
E rror

3
1
2

1 .4 g
.24
1 .2 4

.24
.62

.30

T otal
X vs Y
E rror

3
1
2

. 016
. 017 4

.91

.0509
.016
.O3 U9

Us ing t h e s a t u r a t e d w eight as a b a s i s , th e c o re s were th e n

a i r - d r i e d f o r a t o t a l p e r i o d o f e le v e n d a y s.

Room te m p e ra tu re and

r e l a t i v e h u m id ity were ta k e n in o r d e r to in s u r e a c o n sta n c y f o r each
d e te rm in a tio n .

M easurements in th e l o s s of w e ig h t due to e v a p o r a tio n

were ta k e n a t tw o-day i n t e r v a l s in o r d e r to d e te rm in e th e l o s s i n amount
and r e l a t i v e r a t e o f w a te r l o s s from u n d i s t u r b e d c o re s w ith o u t ground
cover.

These v a l u e s were th a n p l o t t e d f o r th e combined A and B h o riz o n s

f o r e ach sam p lin g area, u s in g a v e ra g e v l a u e s .

R eco rdin g s o f t h e l o s s in

s o i l w a te r were made u n t i l t h e l o s s in w eig ht r e a c h e d a c o n s t a n t amount.
The o b j e c t i v e o f t h i s euroeriment was to d e te rm in e th e e v a p o r a tio n l o s s on
u n d i s t u r b e d c o r e s w ith o u t ground c o v er
v a l u e s a r e g iv e n i n T a b le IS .

or tra n s p ira tio n a l lo sse s.

These

87
TABLE l g .
ACCUMULATIVE AMOUNT AND RATE OF SOIL MOISTURE EVAPORATION FROM SOIL CORES
WITHOUT GROUND COVER IN AREA X AND AREA Y

W ater l o s s - grams a i r - d r y
A rea X ( S t a t i o n s I - I I )

f t . S atu rated
Core

72
Loss

Time in h o u rs
216
120
168
Loss Loss Loss

261+
Loss

T otal
Accumulative

IA]
h
B£
B,

982.2
IOU3 . 2
1092.6
1 0 7 9 .^

5 7 .6
65.7
5 I+.1+
^ 3 .3

2 8 .6
2 3 .O
30.2
1 9 .7

1 6 .9
19.5
16.5
13.2

13.8
10.6
9 .8
11.0

7 .0
M
4 .5
6.7

123.9
123.7
115.1+
9 3.9

11 A]
Ar
Bt

1060.0
IO 5 8 . 5
1067.3
IO 5 I .3

38.8
1+2.7
1+2 . 9
61+. 6

2 3 ‘9
29.0
21+. 1+
22.2

20.8
17.8
16.0
11.2

13.6
1 0 .5
12.5
9 .7

9.U
5.0
7.0
3 .5

106.5
105.0
102.8
111.2

T otal I - I I

882.1+

Area Y ( S t a t io n s I I I - ■IV)
I IIA i
a2
b2

IO 3 5 . 8
1027.3
1067.5
1 0 55 .7

^7-9
53.3
1+6 . 1
^ 9 .7

2 5.9
22.5
25.6
22.5

20.0
1 3.3
16.3
10.5

17.0
9 .7
1 9 .5
7 .0

8.0
8.0
12.0
3 .9

1 18 .8
106.8
119.5
93-6

IVAx
A2
b2
Bt

1 02 3.7
98 U .8
101+1+.0
1020.8

55 a
66.8
1+U. 0
87-7

27.8
21+.S
2 2.5
16.1

16.5
21.2
2 3 .U
8.3

13.0
13.0
15.1
5.2

6.0
7 .5
5.6
5 .0

118.7
133.3
110.6
122.3

T o tal III-IV

9 23 .6

D is c u s s io n o f R e s u lts
The r e s u l t s on t h e r e l a t i v e amount o f e v a p o r a tio n show t h a t A rea Y
h a s a h i g h e r e v a p o r a t i o n l o s s f o r th e e n t i r e p r o f i l e th a n A rea X.

The

a cc u m u la te d amount o f w a te r l o s t in grams f o r an e le v e n -d a y p e r i o d f o r
A rea Y i s 9 2 3 . 6 grams as compared to a l o s s o f 882.1+ grams in A rea X.
This t o t a l p r o f i l e e v a p o r a t i o n l o s s r e p r e s e n t s a t o t a l a ccu m u lated l o s s

P ig . 1 3 .

THE AMOUNT AND RATS OP SOIL MOISTUPE EVAPORATION
L 0 3 3 USING NATURAL SOIL GORES WITHOUT GROUND
COVER IN AREA OP GOOD HEIGHT GROWTH AND POOR
HEIGHT GROWTH

H o r i z o n s A-. - A,

60

A rea X
- - A rea Y
40
W a te r
L oss
In c c .

20
10
i___________________ i___________________ i___________________ i___________________ i—

72

120

168
Tim e - H o u r s

216

264

H o r i z o n s B0 -B
60
A rea X
50

— A rea Y

40
W a te r
L oss
I n c c • 30

20

10

120
T im e -

168
H o u rs

216

89

d i f f e r e n t i a l o f 1+1.2 grams betw een Area. X and A re a Y.

E x p re s s e d a s a

p e r c e n t a g e l o s s from s a t u r a t i o n , th e t o t a l l o s s would be 11 .1 8 p e r c e n t
f o r A re a Y and 10.1+6 p e r c e n t f o r A rea X.

I f th e e v a p o r a tiv e s u r f a c e is

c o n s i d e r e d a s b e in g o n ly th e A^ and A^ h o r i z o n s , th e n th e a c c u m u la tiv e
l o s s d i f f e r e n c e be tw ee n t h e two a r e a s would be 7*1 grams f o r th e A^
and 1 1 . 1+ grams f o r t h e A^ h o r i z o n .
A s i m i l a r s i t u a t i o n e x i s t s w ith r e f e r e n c e to t h e r a t e a t which
ev ap o ratio n ta k es p la c e .

For A rea X, t h e l o s s in w a te r f o r th e f i r s t

f o r t y - e i g h t h o u rs o f e v a p o r a tin g tim e in th e combined A^j^tp h o r iz o n s is
a t th e r a t e o f .5 2 grams p e r h o u r , w hereas th e r a t e f o r A rea Y i s .61+
grams p e r h o u r .
th e r a t e

A f t e r th e i n i t i a l l o s s f o r a p e r i o d o f n i n e t y - s i x h o u r s ,

and amount o f w a te r l o s s te n d s to l e v e l o f f in b o th a r e a s a t

a b o u t th e same m a g n itu d e .
ences in th e combined
A rea Y.

A p p ro x im a te ly th e same r a t e of l o s s d i f f e r ­
h o r iz o n s i s e v id e n t f o r b o th A rea X and

The a c t u a l amount o f w a te r l o s s i s g r e a t e r in th e A h o r iz o n

th a n in th e B h o r i z o n f o r b o th a r e a s .

Curves showing th e r a t e and amount

o f w a te r

l o s s b r i n g o u t t h e s e r e l a t i o n s h i p s more c l e a r l y ( F i g s . 13 and ll+) •

S.

M oisture Evaporation

S o il

(Sim ulated G-round Cover)

Experimental Method:
In order to o b ta in data concerning the s o i l water evaporation
l o s s w ith a sim ulated ground c o v er , the same core samples were used as
th o se f o r e va p o ra tio n l o s s w ithout ground cover*

A fte r s a tu r a tin g the

c o r e s , a sawdust mulch sim u la tin g a c tu a l ground cover was then ap p lie d
to each c o r e .

The amount o f sawdust and depth a p p lie d to samples from

Area X was tw ice th e amount added to samples of Area Y.

This sawdust

90

r a t i o o f 2 : 1 i s a p p r o x im a te ly th e a c t u a l r a t i o o f l i t t e r (w e ig h t "basis)
t h a t i s found, i n th e f o r e s t p l a n t a t i o n *

The o b j e c t o f th e sim ulated,

ground, c o v e r m easurem ents was to d e te r m in e what e f f e c t th e f o r e s t l i t t e r
would have upon th e amount and r a t e o f e v a p o r a tio n from u n d i s t u r b e d
h o riz o n s , e x clu siv e of tr a n s p ir a tio n a l lo s s e s .
r e c o r d e d f o r a t o t a l p e r i o d o f e le v e n d a y s.

The l o s s in w e ig h t was

These r e s u l t s a r e g iv e n

i n T a b le 19*
D is c u s s i o n of R e s u l t s
As b e f o r e , in th e e x p e rim e n t w ith o u t ground c o v e r , t h e amount o f
w a te r l o s s due to e v a p o r a tio n was g r e a t e s t in A rea Y.

The a ccu m u lated

amount o f w a te r l o s s f o r th e combined p r o f i l e f o r a p e r i o d o f e le v e n
days was 1191*1 grams f o r A rea Y as compared to a l o s s of 1099*1 grams
f o r Area. X.

T h is e v a p o r a tio n l o s s f o r th e e n t i r e p r o f i l e r e p r e s e n t s a

t o t a l a.ccum ulated l o s s d i f f e r e n t i a l betw een th e two a r e a s o f 91*3 grams.
The t o t a l l o s s from th e s a t u r a t i o n p o i n t i s 13*^0 p e r c e n t f o r A rea Y and
1 2 .0 7 p e r c e n t f o r A re a X, when t h e e n t i r e p r o f i l e i s c o n s id e r e d .
I f th e e v a p o r a t i v e s u r f a c e i s c o n s id e r e d as b e in g o n ly th e A-^ and A2
h o r i z o n s , th e a c c u m u la tiv e l o s s d i f f e r e n c e betw een th e two a r e a s would
be 6 5 . 2 grams f o r th e A-^ h o r iz o n and 2h.Q grams f o r th e A,-, h o r i z o n .

A

s i m i l a r s i t u a . t i o n e x i s t s w ith r e f e r e n c e to th e r a t e a t which e v a p o r a tio n
ta k e s p l a c e .

F o r A re a X, th e l o s s in w a te r f o r th e f i r s t f o r t y - e i g h t

h o u rs f o r t h e combined A^-Ag h o r iz o n i s a t th e r a t e of 1 . 2 6 grams p e r
h o u r, w hereas th e r a t e f o r A rea Y i s I . 7 6 grams p e r h o u r.

A f t e r th e

i n i t i a l l o s s in w a te r t h e amount and r a t e tend to l e v e l o f f a t a p p ro x i­
m a te ly t h e same m a g n itu d e .

The amount o f w ater l o s s i s g r e a t e r in th e

B h o r iz o n th a n in th e A h o riz o n f o r A rea X; how ever, th e w ater l o s s i s

91
TABLE 1 9 .
ACCUMULATIVE AMOUNT AND RATE OF SOIL MOISTURE EVAPORATION FROM SOIL CORES
WITH SIMULATED GROUND COVER IN AREA X AND AREA Y

Water l o s s - grams a i r - d r y
A rea X ( S t a t i o n s I - I I )

H o riz o n

Wt. S a t u r a t e d

72
Loss

Time in h ou rs
216
120
l5 s
Loss Loss Loss

■264
Loss

94.1
S3.0
82.0
94.9

28.9
21.0
2 4 .4
21.9

12.0
13.5
12.3
11.2

7 .2
4 .o
5.0
4 .1

152.5
12S. 7
132.0
139*0

74.0
85-5
97*4
116.1

19.9

12.s
13.1

3.2
7.1
7.3
3*7

116.7
137.0
l 4g «3

T o ta l
A c cu m u lative Loss

Core
IAi
a2
b2

b3

IO63.O
1123.0
1 1 7 1 .0

ll6 s.5

IIA n

llHi.o

a2

1150.0
II63.O
1126.0

b2

b3

2 1 .0
22. k

s.6

1 2 .2

10.7

10.3
7 .2
8 .3

6.9
6.8
1 0 .3

9 .0
6.5

T o ta l I - I I

1 ^ 5 .6

1099.8

A rea Y ( S t a t i o n s I I I - I V )

5.7

7-5
7 .7
7-5
3 .6

1 4 9 .2
137.0
11S.5
142.9

10.1
9*g
1 0 .4
o.S

S. 2
6.2
S .3
5*7

IS5 .2
152.7
151.6
154.0

T o ta l I I I -I V

1191.1

11 LA,
Ao(2.
B ci
?
b3

1111.5
1100.0
113 s . 5
1123.6

109.0
86.3
69.3
106.3

10.3
is .3
s .9
l4 .i

12.1
13. S
17.S
1 3 .2

10.3
10.9
15.0

IVAn

1131.5
105 s . 4
1123. s
1079.0

135.3

1 9 .5
26.7
24.9
13 .7

12.1
l4 .l
1S.1
10.0

a2
Bp
B-^

95.9
S9.9
112.3

g r e a t e r i n th e A h o r iz o n th a n in th e B h o r iz o n f o r A rea Y.

T h is te n d s

to s u b s t a n t i a t e th e f a c t t h a t th e l i t t e r i s e f f e c t i v e in h o ld in g th e
w a te r a t a lo w e r h o r i z o n in A rea X.

I n A rea Y where th e l i t t e r i s

s p a r s e , th e s o i l w a te r te n d s to e v a p o r a te from th e s u r f a c e h o r iz o n more
re a d ily .

However, u n d e r a c t u a l f i e l d c o n d i t i o n s , th e a i r tu r b u l e n c e or

92

F ig . 1 4 ,
THE AMOUNT AND RATS OF 3 0 IL MOISTURE EVAPORATION
LOSS USING- NATURAL SOIL CORES WITH SIMULATED
-GROUND COVER IN AREA OF GOOD HEIGHT GROWTH AND
POOR HEIGHT GROWTH
H o r i z o n s A^-Ag
A rea

100

"" A r e a

80
W a te r
Loss
6o
In ec *
AO
20

120

168

216

Tim e - H o u r s

H o r i z o n s B g -B ^
A rea
100

W a te r
L oss
I n cc .

-- A rea

60
40
20

168

120
T im e -

H o u rs

216

264

93

wind v e l o c i t y would "be an im p o r ta n t f a c t o r to c o n s i d e r in c o n ju n c t io n
w ith t h e l i t t e r e f f e c t .

A ir t u r b u l e n c e would be e s p e c i a l l y im p o rta n t

in a f f e c t i n g th e r a t e o f s o i l e v a p o r a t i o n .
The r e s u l t s on e v a p o r a t i o n l o s s w ith and w ith o u t ground c o v e r do
n o t show any s i g n i f i c a n t s t a t i s t i c a l d i f f e r e n c e s in e i t h e r th e r a t e o r
amount of ws,ter l o s s .

"Under b o th s e t of c o n d i t i o n s , however, Area Y

l o s t more w a te r and a t a f a s t e r i n i t i a l r a t e th a n A rea X.

Thus, th e

same r e l a t i o n s h i p e x i s t s in b o th c a s e s w ith o r w ith o u t ground c o v e r .
S in c e t h e c o re s were a i r - d r i e d a t th e same te m p e ra tu re and r e l a t i v e
h u m id ity in b o th c a s e s and f r e e o f any t r a n s p i r e ! i o n a l l o s s e s ,

i t is

a p p a r e n t t h a t s o i l t e x t u r e and i t s a t t e n d a n t p o re space must be c o n t r i b ­
u t i n g to t h e d i f f e r e n c e in w a te r l o s s of th e two a r e a s .

I t i s r e a s o n a b le

to assume t h a t u n d e r h ig h e r te m p e ra tu re s o f c r i t i c a l p e r i o d s in th e
grow ing s e a s o n , t h e s e d i f f e r e n c e s would be m a g n ifie d many t i m e s .

This

a s s u m p tio n i s d e f i n i t e l y b orn e o u t by t h e r e s u l t s ta k e n in th e e x p e r i ­
m e n ta l a r e a as o b t a i n e d w ith th e atmometer b u lb th ro u g h o u t two growing
seasons.

These d a t a a r e p r e s e n t e d u n d e r th e c l i m a t i c p h ase of th e

in v e stig a tio n .
An a n a l y s i s o f v a r i a n c e f o r s o i l m o is tu re e v a p o r a tio n is g iv e n by
s o i l h o r i z o n in T a b le 20.

94

TABLE 20 .
ANALYSIS OF VARIANCE FOR ACCUMULATIVE AMOUNT OF SOIL MOISTURE EVAPORATION
LOSS FROM SOIL CORES WITH AND WITHOUT GROUND COVER AREA X v s . AREA Y

B a s i s : 20 sam ples
Water l o s s in c u b ic c e n t i m e t e r s
Ground Cover A bsent
H o riz o n
^1

A

C

®2

B3
J

Source

D eg rees o f Freedom

T o tal
X vs Y
E rror

3

T otal
X vs Y
E rror

3

T o tal
X vs Y
E rror

3

T o tal
X vs Y
E rro r

1
2

1

2
1
2

3
1

2

Sum o f Squares

Kean Square

F

163.99
12.60
151.39

12.60
75.69

.166

558.46
32.49
525.97

32.49
262.9S

.123

15^.39
3 5 . 4o
11S.99

35.40
59.49

.595

590.65
29.16
561.49

29.16
2S0 .7 4

.103

S im u la te d Ground Cover

At
JL

h .

c.

Bp

B,
3

2351.5s
1062.76
12SS.S2

1062.76
644. 4i

1.649

301.69
144.00
157.69

144.00
7 8 . S4

1 .826

2

706.66
26.01
680.65

26.01
340.32

.076

3
l
2

121,21
37.82
S3-39

3 7 . S2
41.69

.907

T o tal
X vs Y
E rror

3

T otal
X vs Y
E rror

3

T o tal
X vs Y
E rror

3

T o tal
X vs Y
E rro r

1

2
1
2

1

95
TABLE 21.
A STATISTICAL SUMMARY OF "F” VALUES FOR EDAPHIC-PHYSICAL
CHARACTERISTICS IN AREA X v s . AREA Y

LABORATORY EXPERIMENTS
S o i l H o rizon

A1
A verage D epth

0-9”

9- 14"

B2

B3

°l

14-23"

23 - 3 3 ”

33”

V a ria b le I n v e s tig a te d :

1.

M e c h a n ic a l A n a ly s is
a . F in e c l a y
b . Sands
c. S i l t p in s clay

11.1**
1.60
.97

l4 .6 * *
1.92
1.31

.13
9.S9
10.63

.07
.67
.67

.00
16.00
16.00

.36

-

-

-

.00

3 .8 4

-

-

-

3.05
.90

2.19
.17
2.76

5-

H y g ro sco p ic C o e f f i c i e n t 1 . 6 7

15.73

6.

Wat e r - h o I d in g Capac i t y
a . Maximum a i r - d r y
b . Maximum n a t u r a l

24.4**
5.35*

4.15
1.36

.96
.027

. 00 [
—

3.21

2.11

.30

.91

2.

S p e c i f i c G r a v ity

3*

Volume Weight

4.

P o re Volume
a. C a p illa ry
b. N o n -c ap illary
c. T o tal p o ro s ity

1.1

.o4

.6 4
.001
1 .8 0

7*

M o is tu re E q u iv a le n t

g.

So i l E v a p o ra t io n
a* W ith ou t g ro un d
. 166
cover
b . S im u la te d ground
1.649
cover

** S i g n i f i c a n t a t 1fa and 5$
* S i g n i f i c a n t a t 5$

.

—
.012

—
—

—

.005

1.17

.123

.595

.103

1.826

.076

.907

—

96

Summary and I m p lic a tio n o f R e su lts
Edaphic-Pbys i c a l C h a r a c t e r is t ic s

Having e s t a b l i s h e d the f a c t from o b s e r v a tio n and measurement th at a
marked d i f f e r e n t i a l r a t e o f h e ig h t growth e x i s t s in the experimented
p l a n t a t i o n under i n v e s t i g a t i o n , a ra th er complete la b o ra to ry a n a ly s is of
the p h y s i c a l s o i l p r o p e r t ie s was undertaken.

The o b j e c t iv e o f both the

p h y s i c a l and chem ical edaphic s t u d ie s was to determine what e f f e c t the
s o i l f a c t o r s might have upon the h e ig h t growth o f t u l i p p o p la r, e it h e r
d i r e c t l y or in combination w ith o th er f a c t o r s .

These s o i l p r o p e r tie s

were i n v e s t i g a t e d s e p a r a t e ly and then combined to show t h e i r r e l a t i v e
a p p l i c a t i o n to each o th er and to r e la t e d p r o p e r t ie s .

For reasons which

are o b v io u s, in an e c o l o g i c a l stu d y , no one f a c t o r per se can be i s o l a t e d
w ithout r e f e r e n c e to i t s a s s o c ia t e d environment.

I t i s th e purpose o f

the p r e s e n t summary to analyze the im p lic a tio n s o f the study thus f a r ,
and to p o in t out th o se f a c t o r s which may be s i g n i f i c a n t l y c o n tr ib u tin g
to th e e n t i r e stu d y .
Three d i s t i n c t but r e la t e d s o i l typ es o f the same s o i l ca ten a were
mapped and p l o t t e d by p r o f i l e .

The ttarsaw sandy loam and Bronson sandy

loam r e p r e s e n t the ar ea o f poor h e ig h t growth; the Fox sandy loam is
r e p r e s e n t a t iv e o f th e s o i l s where the h e ig h t growth i s b e t t e r .

From the

sta n d p o in t o f t e x t u r e , the s o i l s in the area of poor h e ig h t growth c o n ta in
a s i g n i f i c a n t l y g r e a t e r amount of f i n e c la y in the ^
in th e area o f good h e ig h t growth.

and k 2 horizons than

I f i t is assumed th at the f i n e c la y

c on ten t has an important bearing upon h e ig h t growth or s i t e q u a l i t y , then
from the t e x t u r a l v ie w p o in t, the s o i l s in the area of good h e ig h t growth

97

s h o u ld r e v e a l t h e h i g h e r f i n e c l a y c o n t e n t .

The r e s u l t s o b ta in e d in

t h i s s t u d y b e a r o u t th e o p p o s i t e s i t u a t i o n .

Thus, s o i l t e x t u r e a lo n e

must not be a l i m i t i n g f a c t o r cau sin g th e d if f e r e n c e in h e ig h t growth.
S o i l t e x t u r e may be masked by the c o n tr ib u tio n o f some oth er f a c t o r or
s e t o f f a c t o r s , such as the s o i l —m oisture or chemical, r e la t io n s h ip *
Sin ce i t i s g e n e r a l l y r eco gn ized th a t loam s o i l s are more fa v o r a b le f o r
f o r e s t growth than e i t h e r c o a rse sands or f i n e c l a y s , one might in f e r
th a t Area Y (poor h e ig h t growth) would produce th e b e s t h e ig h t growth.
A gain, t h i s s i t u a t i o n i s r ev e r se d as borne out by the mechanical a n a ly s is
o f the th r e e s o i l t y p e s , s in c e the s o i l most c l o s e l y approaching a loam
i s found in Area Y.
The s p e c i f i c g r a v i t y o f the s o i l s in both areas did not d i f f e r
s i g n i f i c a n t l y , e i t h e r in a c tu a l v a lu e or s t a t i s t i c a l l y .
A comparison o f volume w eights shoved very l i t t l e d if f e r e n c e in the
two a rea s i n v e s t i g a t e d .

The volume weight v a lu e s do r e v e a l the f a c t that

in a l l the s o i l s s t u d ie d , the v a lu e s were f a i r l y high, thus p o in tin g out
th a t th e s e s o i l s are not “mature” f o r e s t s o i l s .

Low organic matter

c o n te n t and high sand content o f a l l s o i l s in v e s t ig a t e d i s in d ic a te d by
the volume w eight v a lu e s .
Greater n o n - c a p i l l a r y , c a p i l l a r y , and t o t a l pore volume i s in d ic a te d
in th e area o f poor h e ig h t growth.

This is p a r t i c u l a r l y tru e fo r the root

zone a r e a , the A and A0 h o r iz o n s .
1
^

The d if f e r e n c e in p o r o s it y between the

two s i t e s i s not extreme, however*
R e s u l t s o b ta in ed from the h ygroscop ic c o e f f i c i e n t d eterm ination corrob­
o r a te the r e s u l t s found in the m echanical a n a l y s i s .

In g e n e r a l, higher

v a lu e s were found in a l l horizons fo r the area o f poor h e ig h t growth,

98
TABLE 2 2 .

A COMPOSITE SUMMATION OF PHYSICAL-EDAPHIC CHARACTERISTIOS
BY SOIL HORIZON NOR AREA OF GOOD HEIGHT GROWTH AND AREA
OF POOR HEIGHT GROWTH OF TULIP POPLAR

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A rea X

Ag

13 .2
12.5

b2

13.b

I A-|

5

6 .U
6.0

13.1
16 .2
18.0
B3
°1

S-b

6.0

61.9
76.7
7 3 -6
91.6
9too

38.1
23.3
26.1+
8.U
6.0

2.60
2.52

1.31
1.60

—

61.1
63.2
76.0
88.0
9too

38.9
36.8
2too
12.0
6.0

2.55
2.61

1.62

—

—

—
—

—

21.0

25.2
16.3

50.1
37.3

—

—

—

—

i.b i

25.9
26.4
—
—

17.5
11.7

—

—

2b.s

—

—

—

—

.to
.^5
.99
.17
.09

4 3 . H .*3
3S.1 . 5 b
—
.61
—
.26
.21

to. 5
26.3
23.3
22.7

6.73
1+. 70
5.66
.78
.25

153
129
132
139

35.2
2to2
25.9
23*3

6.93
4.90
5.S6
2.25
.28

117
137

59.6
63.6
52.5
30.1
28.0

3S.9 7.79
32.7 11.
27.6 10.73
20.9
.7^
—
— .54

lbs

57.^
57.3
14-6.7
36.0
29.0

32.9
29.2
25.5
214-.5

58.1

to.9
to . 3
28.3
28.5
56.9
bb.b

39.3
31.3
29-5

—

—

—

ito

1U6

—

A rea Y

n iA ! 1 5 .b
a 2 18.0
b 2 23.1
B, 5.0
°1

u.u

ITAX

lto9

19.1
B22 2 0 . b
b 3 9 -b
Cl b . b

56.9
61.7
7 0 .^
9too
95-0

^3.1
38.3
29.6
6.0
5. 0

2.39
2.7U

61.5
62.7
67.6
90.0
9U.6

3^-5
37.3
32. b
10.0
5 -b

2.S1+
2.76

—
—

—
—

1.33
1.14-6

—
—

1.3b

1.56

—
—

26.0
29.1

—
—-

28.0
26.7

—
—

21.5
15.3

—
—

22.2
13.8

—.
—

^7.5

.zb

—
—

1.05
1.23
.08
.08

50.2

to. 5
—
—

.to
.81
.6k

.33
.09

—

6.99
b.67
6.6s
1.31
.28

137
119
1U3

—-

185
153
152
151+

—

99

■where th e h ig h e r c o n te n t o f c o l l o i d s i s p r e s e n t .

The d if f e r e n c e is not

s t a t is t ic a lly sig n ific a n t.
The water—h o ld in g c a p a c ity o f s o i l s in the a r ea of poor h e ig h t growth
r e v e a ls a h ig h ly s i g n i f i c a n t d i f f e r e n c e in the A^ horizon when compared
w ith Area X.
o f Area Y.

This r e s u l t i s in accord w ith the high er f i n e c la y content
The v a lu e s o btained f o r t h i s s o i l property are in d ic a te d as

s i g n i f i c a n t in both a i r —d r ie d and s ie v e d samples, as w e ll as w ith n atural
s o il cores.
A measure o f the m oistu re e q u iv a le n t in both areas d i s c l o s e s no
s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e between th e two s i t e s .

However, use

o f the m o istu re e q u iv a le n t as a measure o f te x t u r e , brings out the f a c t
th a t th e v a lu e s in c r ea se d w ith an in c r e a se in c o l l o i d a l c o n te n t.

Again,

the area o f poor h e ig h t growth showed the higher m oisture e q u iv a len t
v a lu e s.
The r e s u l t s on the measurement o f s o i l water evaporation l o s s from
n a tu r a l s o i l co res r e v e a ls both a g r e a t e r amount and i n i t i a l r a te of
ev a p oratio n l o s s from th e area o f poor h e ig h t growth.

Although the a c tu a l

v a lu e s show no s t a t i s t i c a l d if f e r e n c e on compared s i t e s , t h i s f a c t o r may
be extrem ely important a t c r i t i c a l p e r io d s of the growing season .

The

e v a p oration experim ents are l i m i t e d in t h e ir s p a t i a l a p p lic a t io n but are
important as an i n d ic a t io n of the s o il- m o i s t u r e r e l a t i o n s h i p s .

I t is

s u f f i c i e n t to p o in t out a t t h i s s ta g e o f the in v e s t i g a t i o n , th a t g r e a te r
i n i t i a l l o s s e s and r a te o f evaporation occur in Area Y, both w ith end
w ithout sim u la ted ground cover.
The s t a t i s t i c a l summary o f a l l p h y s ic a l s o i l f a c t o r s under i n v e s t i ­
g a tio n r e v e a ls o n ly two p r o p e r tie s o f s t a t i s t i c a l s i g n i f i c a n c e .

These two

100

f a c t o r s , th e amount o f f i n e c la y and th e w a te r-h o ld in g c a p a c ity , a,re the
o n ly v a r i a b l e s which d i f f e r s i g n i f i c a n t l y between Area X and Area Y.

It

i s important to n o te that th e s e two s o i l p r o p e r tie s are d e f i n i t e l y r e la t e d
to each o t h e r , insofa,r as the s o i l - m o i s t u r e r e l a t i o n s h i p i s concerned.
The manner in which the more ou tstan d in g p h y s ic a l s o i l v a r ia b le s
r e l a t e to th e c l i m a t i c , ch em ica l, and m ic r o b io lo g ic a l phases o f the
p r e s e n t i n v e s t i g a t i o n w i l l be d is c u s s e d and analyzed in th e f i n a l summary
of a l l fa c to r s.

101

D epth o f Root P e n e t r a t i o n in R e l a t i o n to th e Ph y s ic a l- E d a p h i c Charac t e r i s t i c s

I n o r d e r to d e te r m in e w h e th er any s i g n i f i c a n t d i f f e r e n c e s e x i s t e d
b etw een th e a r e a s o f good and p o o r h e i g h t gro w th t? ith r e s p e c t to e x t e n t
o f l a t e r a l r o o t p e n e t r a t i o n , p r o f i l e s ex p o sin g th e r o o t system were made
i n e a c h a r e a ( F i g s . 15 and 1 6 ) .

These p r o f i l e s were dug a t random

l o c a t i o n s in each a r e a and t h e r o o t p e n e t r a t i o n d e p th s were re c o rd e d
t h r o u g h o u t t h e grow ing s e a s o n in o r d e r to a r r i v e a t a s u b s t a n t i a l a v e ra g e
ro o t d ep th p e n e tr a ti o n .

A r e c o r d o f th e p r o f i l e s exposed and t h e i r c o r r e ­

sp o n d in g d e p th s i s as f o l l o w s ;
P ro file
1
2
3
k

5

6
7
S
9
10
11
12

D ate Exposed
A p r i l I S , 1952
ft
ti
it
May 20, 1952
ti
ti
ti
June 20, 1952
ii
11

tt
J u ly 31, 1952

ih

11

15
16
17

ti
A ugust 3 1 * 3-952

11

is

11

19
20

11
11

S ta t ion
I
II
III
17

S ta tio n ¥0 .

D epth o f Maximum L a t e r a l
Root P e n e t r a t i o n in In ch es

I
II

11.0
10.0
15.0
19.0
15.0
13.0
10.0
1 3 .0
13.0
12.0
11.0
16.0
16.0
13.0
12.0
15.0
12.0
1 1 .0

III
IV

lU.Q
1S.0

I
II
III

17
I
II
III
IV
I
II
III

IV
I

II
III
IV

Average Depth Root P e n e tr a tio n in
1 3 .^
l i . s

12.h
17.2

10??

F i g . 15.
A s o i l p r o f i l e exposed in th e a r e a o f good h e i g h t growth
(A rea X ). The e f f e c t i v e d e p th o f l a t e r a l r o o t p e n e t r a t i o n in
t h i s a r e a i s a p p ro x im a te ly 11 in c h e s . The c o n c e n t r a t i o n o f
f l e s h y l a t e r a l r o o t s o f t u l i p p o p la r a r e found e x c l u s i v e l y in
t h e ’’A" s o i l h o r i z o n . Note th e hardwood l e a f l i t t e r a t th e
s o il surface.

103

In hardwood s p e c ie s such as t u l i p p o p la r , the depth and form o f root
system appears to he c o r r e la t e d w ith water c on ten t o f the s o i l .

Tulip

p o p la r i s a s p e c ie s w ith long i n i t i a l ta p ro o ts and prominent l a t e r a l s .
Most e v id e n c e r e v e a l s t h a t t h i s t y p e r o o t system i s c h a r a c t e r i s t i c o f
s p e c i e s r e a c h i n g optimum developm ent on s o i l s w hich, hecau.se o f t h e i r
p h y s i c a l p r o p e r t i e s and p r o f i l e c h a r a c t e r i s t i c s , have a f a i r l y u n ifo rm
a v a i l a b l e w a te r c o n t e n t th ro u g h o u t.

Such s o i l s a r e n e c e s s a r i l y deep,

w e l l - d r a i n e d and o f u n ifo rm t e x t u r e w i t h m od erate p e r m e a b i l i t y .

A ccording

to Tourney and K o r s t i a n (1937) t u l i p p o p l a r draws i t s w a te r and n u t r i e n t
s u p p l i e s v e r y l a r g e l y from th e s u r f a c e l a y e r s o f th e s o i l , a l th o u g h t h i s
s p e c i e s h a s a d e e p ly p e n e t r a t i n g t a p r o o t .

T h is f a c t i s s u b s t a n t i a t e d i n

th e p r e s e n t i n v e s t i g a t i o n as shown by exposed p r o f i l e and r o o t d e p th
p e n e t r a t i o n m easurem ents.

Hoot p o s i t i o n r e f l e c t s to a g r e a t d e g re e th e

s o i l m o i s t u r e c o n d i t i o n s , and a s tu d y o f r o o t h a b i t g iv e s v a l u a b l e in ­
f o r m a ti o n on t h e a d a p t a b i l i t y o f v a r i o u s s p e c ie s f o r a. p a r t i c u l a r s i t e .
R e su lts and [Discussion
From th e r e s u l t s ob ta in ed on the exposure o f l a t e r a l r o o ts in twenty
in d iv id u a l p r o f i l e s o f both Area. X and Area T, -no extreme d if f e r e n c e s were
found in depth o f root p e n e tr a tio n .

The g r e a t e s t root p e n e tr a tio n o f the

fou r l o c a t i o n s exposed was n in e te e n in c h e s.

The average depths obtained

fo r each o f fou r sep a ra te s t a t i o n s shows the g r e a t e s t p e n e tr a tio n at
S t a tio n IV.

As in d ic a te d by s o i l type and poor h eig h t growth, t h i s s o i l

i s th e d r i e s t of the fou r s t a t i o n s observed.

I t is surmised th at the

deeper root development o f t h i s area is i n d ic a t iv e of a d r ie r s i t e than
oth er l o c a t i o n s in the experim ental t r a c t .

The water ta b le l e v e l at the

10U

P ig . l 6 .
A s o i l p r o f i l e exposed in the area o f poor h e ig h t grovrth
(Area Y ). The e f f e c t i v e depth o f l a t e r a l root p e n e tr a tio n in
t h i s l o c a t i o n i s approximateljr 15 inches; the f l e s h y l a t e r a l
r o o t s are found e x c l u s i v e l y in the ,,A11 s o i l h o rizon . Note the
dominant g r a ss v e g e t a l l i t t e r ;it the s o i l su r fa c e in c o n tr a st
t o the l e a f l i t t e r o f Area X.

105

same s t a t i o n i s c l o s e r to the ground s u r fa c e than at any o th er s t a t i o n .
I t i s e n t i r e l y p o s s i b l e th a t the deeper ro o t p e n e tr a tio n in t h i s l o c a t i o n
i s in f lu e n c e d by s a tu r a te d s o i l c l o s e to the water t a b le l e v e l during the
e a r ly p a r t o f the growing seaso n .

Again, during the

and summer drought, th e r o o ts o f t r e e s at S t a t io n IT

dry p e r io d o f August
maybecome more

d e e p ly p e n e t r a t in g in respon se to a v a ila b le s o i l m oisture vrith a c o rre­
sponding drop in the water t a b le l e v e l .

The downward growth o f r o o ts must

heep pace w ith the l o s s o f m oistu re from the s u p e r fic ia l, la y e r s o f s o i l
during th e p e r io d o f drought.

The root system o f t u l i p p o p la r , which i s

f l e s h y and s u c c u le n t , i s not ad. ju s ted to s i t e s which

are swampy or to

th o se s i t e s in which the s u r fa c e la y e r s are su b jec t to d e s i c c a t i o n .

Thus,

the r e s u l t s here o b ta in e d denote th a t t u l i p pop lar i s adapting i t s e l f ,
w ith regard to i t s ro o t system , to a c o n d itio n somewhere between the
extreme l i m i t s o f s a t u r a t io n and p h y s i o l o g i c a l d ry n ess.

The e f f e c t i v e

zone o f l a t e r a l r o ot p e n e tr a tio n f o r both Area X and Area Y i s found
e n t i r e l y in th e Ap and Ag s o i l h o r iz o n s .

The e f f e c t s o f e v a p o r a tio n ,

s o i l tem perature, and s o i l m oisture fo r th ese h o r iz o n s , in r e l a t i o n to
r oot p e n e t r a t io n , w i l l be d is c u s s e d under c lim a t i c i n v e s t i g a t i o n s .

It is

i n t e r e s t i n g to note th a t the on ly s t a t i s t i c a l l y s i g n i f i c a n t t e x t u r a l s o i l
d i f f e r e n c e between Area X and Area Y i s found in the same ho rizon s (A-j_ amd
A^) as th e e f f e c t i v e zone o f l a t e r a l r o ot p e n e tr a tio n .

Thus, in d is c u s s ­

ing th e e f f e c t o f c l i m a t i c f a c t o r s on s o il- m o i s t u r e r e l a t i o n s h i p s in t h i s
stu d y , v i r t u a l l y a l l r e l a t i o n s between growth and s o i l m oistu re w i l l
r e f e r to the l a t e r a l root zone a r ea , s in c e t h i s i s the zone where the
t r e e s are p r im a r ily d e r iv in g t h e i r n u t r ie n t s and water supply.

The r o le

10 6

o f f e e d e r r o o t s in r e l a t i o n to w a te r s u p p ly i n e ach a r e a vjas n o t in­
v e stig a te d ,
(ta p ro o ts)
g ro w th .

T h is i s n o t t o imply t h a t t h e more d e e p ly e n tr e n c h e d r o o t s
a r e n o t im p o r ta n t in s u p p ly in g w a te r a t c r i t i c a l p e r i o d s o f

E f f e c t i v e l a t e r a l r o o t p e n e t r a t i o n and i t s r e l a t i o n to th e

p h y s i c a l - e d a p h i c c h a . r a c t e r i s t i c s o f t h e e x p e r im e n ta l a r e a was th e
o b j e c t i v e o f t h i s p h a s e o f th e s tu d y .

loy

W ater T a b le F l u c t u a t i o n in R e l a t i o n to th e P h y s ic a l - E d a p h ic Char a c t e r i s t i c s

T hro ug h ou t th e grow ing s e a s o n o f 1952, th e d e p th to t h e u n d e r ly in g
w a te r t a b l e was r e c o r d e d f o r com parison "between th e a r e a o f good and po o r
h e i g h t g ro w th o f t u l i p p o p l a r .
t a b l e i s shown in F i g . 1 7 .

T h is f l u c t u a t i o n in d e o th to t h e w a te r

A c o n tin u o u s drop in wa.ter t a b l e l e v e l , as th e

s e a s o n p r o g r e s s e d , i s g r a p h i c a l l y r e c o r d e d f o r b o th A rea X and A rea Y.
S in c e i t h a s b e en shown by s e v e r a l i n v e s t i g a t o r s t h a t c a p i l l a r y r i s e
o f w a te r from a w a te r t a b l e w i t h i n f i f t e e n f e e t o f th e s u r f a c e is im p ort­
a n t in p r o v i d i n g r o o t s w ith m o i s t u r e , f l u c t u a t i o n s in th e w a te r t a b l e f o r
t u l i p p o l a r a r e s i g n i f i c a n t in term s o f t r e e g ro w th .

The waiter t a b l e in

A rea X o c c u r s a t an a v e ra g e d e p th o f a p p ro x im a te ly s i x f e e t , whereas
A re a Y h a s a w a te r t a b l e o c c u r r i n g a t a p p ro x im a te ly t h r e e f e e t below th e
su rface.
R e s u l t s and D is c u s s i o n
The c h a r a c t e r o f th e v e g e t a t i o n h a s an im p o rta n t e f f e c t upon th e
h e i g h t o f th e w a te r t a b l e and o t h e r f a c t o r s a s s o c i a t e d w ith t h e w a te r
ta b le le v e l.

I n A re a X th e t r e e s a r e more m assiv e in h e i g h t and volume

and hence r e q u i r e more w a te r f o r t r a n s p i r a t i o n a l p u r p o s e s ; t h i s w a te r is
drawn from t h e g rou nd w a te r s u p p ly o r e l s e from t h e s o i l b e f o r e i t p en e­
t r a t e s to t h e w a te r t a b l e l e v e l .

T h is o b s e r v a t i o n , co u p led w ith such

r e c o r d e d c l i m a t i c f a c t o r s a s re d u c e d s o i l w a te r e v a p o r a t i o n , low er s o i l
t e m p e r a t u r e s , re d u c e d s u r f a c e s o i l t e m p e r a t u r e s , and a sandy loam s o i l
ty p e , c o n t r i b u t e d i r e c t l y to t h e low er w a te r t a b l e l e v e l in A rea X.

In

c o n t r a s t to t h i s s i t u a t i o n , A rea Y p o s s e s s e s a w a te r t a b l e c l o s e to th e
s u r f a c e a s a r e s u l t o f in c r e a s e d c a p i l l a r i t y and in c r e a s e d s o i l evapo­
ra tio n .

The s o i l o f A rea Y is a deep s o i l in an a b s o l u t e s e n s e , b u t ,

10s
F ig .

1 7 .

THE WATER-TABLE FLUCTUATION THROUGHOUT
THE GROWING 3EA30N OF 1 9 5 2

A rea X

I
II

A rea Y
III
---------------- IV

20

40
D e p t h To
W a te r-T a b le
In
In ch es
60

80

100

A p ril

May
June
M o n th o f O b s e r v a t i o n

J u ly

A ugust

109

b e c a u s e o f a r e l a t i v e l y im p erv io u s l a y e r ( h i g h c la y c o n t e n t o f A h o riz o n )
and h i g h w a te r t a b l e ,

i t i s a s h a llo w s o i l in a p h y s i o l o g i c a l s e n s e , which

i n h i b i t s norm al h e i g h t g ro w th .

A c l i m a t i c s tu d y o f t h e c o n t r a s t between

b o t h a r e a s u t i l i z i n g such f a c t o r s as r e l a t i v e h u m id ity , s o i l e v a p o r a tio n
l o s s , a i r and s o i l te m p e r a t u r e , s o i l - m o i s t u r e r e l a t i o n s h i p s and wind
movement, b e a r o u t t h e c o r r e l a t i o n betw een th e w a te r t a b l e l e v e l s in each
area.

E x p e rim en ts have shown t h a t c a p i l l a r y r i s e o f w a te r in s o i l s ta k e s

p l a c e s lo w ly , b u t t o th e g r e a t e s t h e i g h t in c l a y s o i l s , and most r a p i d l y
in sandy s o i l s .
From t h e r e s u l t s o f th e w a te r t a b l e f l u c t u a t i o n in b o th a r e a s i t is
a p p a r e n t t h a t th e w a te r t a b l e l e v e l

in p l a n t a t i o n s o f t h i s ty p e becomes

im p o r ta n t a s an in d e x to p l a n t i n g s i t e s ,

i n s o f a r as th e s e d a t a a r e s u p p le ­

m ented w i t h o t h e r c l i m a t i c and e d a p h ic f a c t o r s .

A gain, th e c r i t i c a l s o i l -

m o i s t u r e r e q u ir e m e n ts f o r t u l i p p o p l a r p l a n t a t i o n s i s e v i d e n t .

Thus,

A rea Y a p p a r e n t l y h a s a l l t h e s i t e re q u ire m e n ts n e c e s s a r y to good h e ig h t
g ro w th o f t u l i p p o p l a r , y e t th e b e s t grow th o c c u r s somewhere beyond th e s e
l i m i t a t i o n s , as e x h i b i t e d by A rea X.

The two main f a c t o r s , as e v id en c e d

by t h i s s tu d y , which a r e c o n t r i b u t i n g most to t h e d i f f e r e n c e in th e w a te r
t a b l e l e v e l s o f b o th a r e a s , a r e e v a p o r a t i o n and t r a n s p i r a t i o n o f th e t u l i p
p o p la r s i t e s .

110

LABORATORY EXPERIMENTS
Chemical - Edaphie C h a r a c t e r i s t i c s
1 . S o i l A c i d i t y (pH)^
E x p e rim e n ta l Method:
Samples f o r th e d e t e r m i n a t i o n o f t h e h y d ro g e n -io n c o n c e n t r a t i o n
we r e ta k e n from f i v e s o i l h o r iz o n s on t h i r t y - t w o randomly s e l e c t e d s p o ts
in A re a X and A re a Y.

Ten-grata s o i l sam ples were ta k e n in d u p l i c a t e in

J u l y 1951* and s e a l e d im m ediately in p a r a f f i n c o n t a i n e r s .

The pH o f each

s o i l was th e n d e te r m in e d e l e c t r o m e t r i c a l l y "by u se o f th e Beckman pH M ete r,
as shown by Reed and Cummings (19^5)» aJ1d th e r e c i p r o c a l v a lu e s o b ta in e d
were a v e r a g e d f o r e ac h d u p l i c a t e s e t o f sam p les.

A s o i l - w a t e r e x t r a c t in

t h e r a t i o o f 1 :1 was u sed in a l l d u p l i c a t e d e t e r m i n a t i o n s .

By means o f th e

U n ite d S t a t e s S o i l C o n s e rv a tio n S e r v ic e c l a s s i f i c a t i o n c r i t e r i a , th e
r e l a t i v e pH and i t s c o r r e s p o n d in g c l a s s of a c i d i t y was p l o t t e d f o r each
a r e a by d e p th o f h o r i z o n .

The a v e ra g e v a lu e s o b ta in e d by h o r iz o n and

d e p th i s p r e s e n t e d in T a b le 2 3 .
D is c u s s i o n o f R e s u l t s
Most f o r e s t s o i l s a r e a c i d in r e a c t i o n .

T his r e a c t i o n i s n o t always

c o n s t a n t b u t shows v a r i a t i o n d u r in g th e c o u rs e of t h e yea.r.

However,

H e h rin g (193^) a German i n v e s t i g a t o r , found t h a t v a r i a t i o n s in pH d id n o t
exceed 0 . 8 pH o v e r a o n e - y e a r p e r i o d .
c o m p arable r e s u l t s .

O th er i n v e s t i g a t o r s have found

Marked d i f f e r e n c e s in pH a r e o f t e n found in d i f f e r e n t

9 . The number p re c ed in g ' th e c h em ical s o i l f a c t o r un d er i n v e s t i g a t i o n
c o rre s p o n d s to th e same f a c t o r summarized s t a t i s t i c a l l y in T ab le *+2.

I ll

TABLE 2 3 .

THE HYDROGEN-ION CONCENTRATION OP SOILS REPRESENTING FIVE SOIL HORIZONS
IN AREA X AND AREA Y
L o g a rith m o f r e c i p r o c a l o f t h e h y d ro g e n -io n c o n c e n t r a t i o n
A rea X ( S t a t i o n s I - I I )
i l H o riz o n

A verage pH

IA-,
a2
b2
b3
cx

5 .5 5
5 .3 3
5 .^ 0
5>2
5 .1 S

IIA j
Ap

5 .3 9
5 .2 0
5 .1 5
5 .1 ^
5 .U0

B2

C31

Combined S t a t i o n s

A verage pH

I- 1 1 An
2
B2
B3
C1

Avg. D i f f e r e n c e

5^7
5 .2 6
5.27
5.2S
5.29

-.1 3
+ .2 1
+ .4 l
+ .2S
-•33

5 .6 0
5.05
U .g 6
5 .0 0
5 .6 2

+ .13
-.2 1
-.U l
-.2 8
+ •33

A rea Y ( S t a t i o n s I I I -IV)
h l a -l

5 .S5
5 .1 6
5 .0 2
5 .1 7
5 . k2

a2
b2
B3
Cl
IVA-j

III-IVA-.
a2
B2
B3

5-35
k .sk
4 .7 0
U.S 3
5.S2

4
B2
B3

** A minus s i g n (■- ) i n d i c a t e s g r e a t e r a c i d i t y th a n compared a r e a
and a p i n s (+) s i g n i n d i c a t e s l e s s a c i d th a n compared area,.
h o r i z o n s of a p a r t i c u l a r p r o f i l e .

I n th e r e s u l t s h e r e o b t a i n e d , c o n s i d e r a b l e

v a r i a t i o n w i t h i n h o r i z o n s may be s e e n , b u t th e f i n d i n g s i n d i c a t e t h a t a
co m p ariso n o f A rea X end A re a Y show l i t t l e o v e r a l l v a r i a t i o n .

The h i g h e s t

pH fo u n d was 5 .S 5 and th e lo w e s t was ^ .7 0 ; t h e s e v a lu e s in c lu d e a l l h o r iz o n s
in b o t h a r e a s .

A rea Y e x h i b i t s lo w er i n d i v i d u a l h o r i z o n a l a c i d i t i e s th a n

A rea X b u t b o th a r e a s a r e in th e c a te g o r y o f s t r o n g l y a c i d to v e ry s t r o n g l y

c—
-

Ti

_ /

-

Cry T3
.

Ti

m
S 7

113

a c i d , when a v e r a g e v a l u e s a r e c o n s i d e r e d .

The B h o r iz o n of A rea X and

A re a Y a p p e a r s to be s l i g h t l y more a c i d th a n th e A o r C h o r iz o n s ( F i g . 1 8 ).
A lso t h e g re a -te r pH d i f f e r e n c e betw een t h e two compared a r e a s o c c u rs in th e
B h o riz o n .
A s tu d y by A uten (19*4-5)

77 s e c o n d -g ro w th y e llo w p o p l a r s ta n d s from

12 to 6 l y e a r s o f age on o ld f i e l d s and c u to v e r a r e a s , showed t h a t i f th e

s o i l r e a c t i o n was c o n s id e r e d a t th e r o o t zone d e p th , most s o i l s were a c i d .
A uten c i t e s an example o f a 1 2 - y e a r o ld s ta n d which grew a t th e r a t e of
f e e t p e r y e a r on a s o i l w ith a pH o f 5*8 a.t th e s u r f a c e and 5*6 in t h e sub­
so il.

T h is s i t u a t i o n i s an alo g o u s to th e r e s u l t s of th e p r e s e n t i n v e s t i ­

g a t i o n , where i n s u f f i c i e n t tim e h a s e la p s e d f o r th e c a lc a r e o u s y e llo w
p o p l a r l i t t e r to a l t e r th e r e a c t i o n to l e s s a c i d c o n d i t i o n s .

In tim e , th e

l i t t e r o f t h i s p l a n t a t i o n w i l l become r i c h e r in lim e and change th e s o i l
r e a c t i o n to n e u t r a l o r s l i g h t l y a l k a l i n e c o n d i t i o n s .
A c co rd in g to L u tz and C handler (19*4-6) t h e r e i s v e ry l i t t l e

e v id en c e

t h a t low pH p e r s e i s r e s p o n s i b l e f o r p o o r grow th o f f o r e s t t r e e s .

A g ri­

c u l t u r a l p l a n t s may be s e n s i t i v e to h ig h c o n c e n t r a t i o n s o f hydrogen ions
b u t t h i s i s l e s s marked f o r f o r e s t t r e e s p e c i e s .

High a c i d i t y v a l u e s ,

how ever, may a f f e c t t h e s o i l f a u n a and f l o r a , c e r t a i n p h y s i c a l and chem ical
f a c t o r s , and even t o x i c i t y of s e n s i t i v e s n e c i e s .

These e f f e c t s a r e i n d i r e c t ,

b u t a l t e r a p e r i o d o f tim e may become h i g h l y im p o r ta n t.

An a n a l y s i s o f

v a r i a n c e shows t h e g r e a t e s t d i f f e r e n c e in pH between A rea X and A rea Y
o c c u r r i n g in th e B2 h o r i z o n .

However, no h o riz o n e x h i b i t s any s t a t i s t i c a l

s i g n i f i c a n t d i f f e r e n c e (T a b le 2 b ).

lib
TABLE

2b.

ANALYSIS OF VARIANCE FOR TER HYDRO G-EN-ION COECENTRATXON OF FIVE SOIL HORIZONS
IN AREA X v s . AREA Y

B a s i s : 32 samples
pH

A1

a2

Source

D egrees o f Freedom

Sum o f S q uares

T o ta l
X vs Y
E rror

15
1
Ik

1 .2 1
.0 6
1 .1 5

.0 6
.032

*73

T o tal
X vs Y
E rror

15
1
1^

1 .2 1
.19
1 .0 2

.19
.073

2 .6 1

Mean Square

F

B a s i s : b sam ples
B2

b3

T o tal
X vs Y
E rror

3
1
2

.25
.17
.OS

.17
.o b

1+.25

T o tal
X vs Y
E rror

3
1
2

.I S
.0 7
.11

.07
.055

1 .3 2

T o ta l
X vs Y
E rror

3
1
2

.21
.1 1
.10

.1 1
.0 5

2 .2 1

2. S o i l O rg a n ic M a tte r
E xperim ental Method:
S o i l sam ples v e r e c o l l e c t e d from A rea X and A rea Y r e p r e s e n t i n g
f i v e s o i l h o r iz o n s in each a r e a .

A t o t a l o f tw enty i n d i v i d u a l sam ples was

ta k e n and t h e s e sam ples v e re a i r - d r i e d and p a s s e d th ro u g h a two mm. s i e v e .
The d ry c o m b ustion method f o r a n a l y s i s o f o rg a n ic m a t t e r was employed.

F iv e

grains o f 60 mesh carb o n f r e e alundum and .25 grams o f manganese d io x id e vas
added to a two gram sample o f s o i l .

These v e re v e i l mixed and p l a c e d in a

s i l i c a co m b ustio n b o a t and i n s e r t e d in to a h o t s i l i c a tu b e f u r n a c e ,

115

TABLE 2 5 .

THE AMOUNT OF SOIL ORGANIC MATTER IN FIVE HORIZONS FROM AREA X AND AREA Y
P ercent
A rea X ( S t a t i o n s I - I I )
H o riz o n

Carbon d io x i d e (gins.)

P e r c e n t carb o n d io x id e *

O rganic M a tte r

IA1
4
B2
B3
°1

.1 0 0
.o b i
.0 3 0
.0 1 5
.0 1 2

1 0 .0
b .l
3 .0
1 .5
1 .2

2-35
.96
-71
-35
.28

IIA 1
a2
b2
B?

.073
.0 3 0
.028
.0 1 7
.0 1 2

7 .3
3 .0
2 .8
1 .7
1 .2

1 .7 2
-71
. 66
.bo
.28

°1

A re a Y ( S t a t i o n s I I I - I V )
IIIA-i
a3
B2
b3
°1
I7A i
A2
b2
B3

.113
.0 5 0
.035
.0 1 5
.0 1 5

11.3
5 .0
3 .5
1 .5
1 .5

2 .6 6
1 .1 8
-S3
-35
-35

.0 7 0
.0 3 8
.0 3 2
.0 1 3
.0 0 6

7 .0
3 .8
3 .2
1 .3
0 .6

I .6 5
.90
-75
•31
.lb

B a s is one-gram sample
* P e r c e n t c a rb o n d i o x id e c o n v e r te d to o rg a n ic m a t t e r by m u l t i p l y i n g
by th e f a c t o r 0 .^ 7 1 ( a f t e r S c h o lle n b e r g e r )
p r e v i o u s l y h e a t e d to at)out 950° C.

A f t e r a p p r o p r i a t e oxygen flo w r a t e was

a d j u s t e d , t h e sample was s u b j e c t e d to v a r i o u s p u r i f i c a t i o n p r o c e s s e s , and
th e n removed a f t e r tw en ty m in u te s .

Carbon d io x id e was o o lle c te u . in a,

p r e v i o u s l y w eighed a s c a r i t e tu b e and th e u e r c e n t o r g a n ic m a t t e r computed by
u s i n g th e f a c t o r O.U71 to c o n v e r t amount o f carb o n d io x id e to o rg a n ic

i**

n6

m a t t e r ( a f t e r S c h o l l e n b e r g e r , 19*+5) *

^he p e r c e n t o r g a n ic m a t t e r was th e n

re d u c e d to a one-gram b a s i s and p l o t t e d to s c a l e ( F i g .

19).

D is c u s s i o n o f R e s u l t s
A dynamic e q u i l i b r i u m e x i s t s betw een th e s u p p ly o f f r e s h o r g a n ic
d e b r i s and i t s s u b s e q u e n t d e c o m p o s itio n .

Changes which a l t e r t h i s e q u i­

l i b r i u m w i l l r e s u l t in e i t h e r a d e c r e a s e o r i n c r e a s e o f o r g a n ic m a t t e r .
The im p o rta n c e o f o r g a n i c m a t t e r in a f f e c t i n g th e p h y s i c a l and ch em ical
c h a r a c t e r i s t i c s o f s o i l s c an no t be o v e r e s t i m a t e d .

The c o m p o sitio n and t h e

q u a n t i t y o f o r g a n ic m a t t e r in s o i l s i s th u s e x tre m e ly v a r i a b l e .

V alues

o b t a i n e d in t h i s i n v e s t i g a t i o n compare q u i t e f a v o r a b l y w ith th e f i n d i n g s o f
many i n v e s t i g a t o r s on s i m i l a n s o i l t y p e s .

A s tu d y by Auten ( l 9 1+5) showed

t h a t y e llo w p o p l a r o f t e n re p ro d u c e s and grows r a p i d l y on deep s o i l s from
which o r g a n i c m a t t e r has been removed by o x i d a t i o n and e r o s i o n .

Thus, i f

y e llo w p o p l a r would n o t r e s e e d , become e s t a b l i s h e d , and t h r i v e on s o i l s
which have a low o r g a n i c c o n t e n t , one m ight deduce t h a t h e i g h t grow th was
d e p e n d e n t upon o r g a n i c m a t t e r .

Such, however, i s n o t th e c a s e .

A lthough

o r g a n i c m a t t e r d e p o s i t e d as l i t t e r i n f l u e n c e s grow th r a t e as th e accumu­
l a t i o n becomes g r e a t e r ,

i t s p r e s e n c e i s n o t a p rim a ry cause o f in c r e a s e d

t r e e g ro w th , b u t a r e s u l t .

An e x a m in a tio n o f th e d a t a o b t a i n e d in T ab le 23

w i l l im m e d ia te ly show t h a t th e amount o f o rg a n ic m a t t e r i s r e l a t i v e l y low
in b o t h A rea X and A rea Y.
d e p th o f t h e p r o f i l e .

I n a l l c a s e s th e amount d e c r e a s e s w ith in c r e a s e d

The h i g h e s t c o n te n t of o r g a n ic m a t t e r o c c u rs on th e

Warsaw sandy loam , a c i d v a r i a n t t y p e , where a t o t a l c o n te n t o f 5 .3 7 p e r c e n t
i s fo u n d f o r th e e n t i r e p r o f i l e ; th e h i g h e s t v a lu e o f 2.b6 p e r c e n t i s a ls o
fo u n d h e r e in th e

h o rizo n .

The re m a in in g s o i l ty p e s do n o t d i f f e r

a p p r e c i a b l y in t h e i r c o n te n t o f o r g a n ic m a t t e r f o r any h o r i z o n .

An

F ig .

19.

1:Ly

PERGSNT OF ORGANIC MATTER EXISTING- IN FIV E SOIL
HORIZONS FOR THE A.REA OF GOOD HEIGHT GROWTH v s .
AREA OF POOR HEIGHT GROWTH

3 .0

2 .7

(i v n
A r e a "X

2 .5

2 .2

A rea " y "

2.0
u
®
4»
4»
£

f1*7
g l
CD

.5

K
©

ft

1.2

1.0

.7

.5

.2

S o il H o riz o n

118

a n a l y s i s o f v a r i a n c e shows th e g r e a t e s t d i f f e r e n c e "between A rea X and
A rea Y o c c u r s in th e A2 h o riz o n *

However, no s t a t i s t i c a l s i g n i f i c a n t

d i f f e r e n c e i n o r g a n i c m a t t e r e x i s t s "between A rea X and A rea Y (T a b le 2 6 ) .
TABLE 2 6 .
ANALYSIS OF VARIANCE OF CffiG-AMIC MATTER IN FIVE SOIL HORIZONS FOR AREA. X v s .
AREA Y
P ercent
B a s i s : 20 sam ples
Source

D egrees o f Freedom

A1

T o tal
X vs Y
E rror

3
1
2

T o tal
X vs Y
E rro r

B3
j

°1

3*

F

.73
.0 2
.71

.0 2
•35

.0 6

3
1
2

.1 1
.05
.0 6

.05
.03

1 . 6l

T o tal
X vs Y
E rror

3
1
2

.0 2
.0 2
.00

.0 2
.0 0

T o tal
X vs Y
E rror

3
1
2

.003
.0 03
.0 0

.003
.0 0

T o tal
X vs Y
E rror

3
1
2

.03
.00
.03

.0 0
.015

.00

0
0

b2

Mean Square

•

A2

Sum o f Squares

0
0

H o riz o n

T o t a l N itr o g e n and C arb o n -H itro g e n R a tio
E x p e rim e n ta l Method:
T o t a l n i t r o g e n was d e te rm in e d 011 combined s u b s t a t i o n d u p l i c a t e

sam ples f o r t h e A and B h o r iz o n s o f A rea X and Area Y*
made a c c o r d in g to th e K j e l d a h l p ro c e d u re ( 1 9 ? 0 ) .

D e te r m in a tio n was

Ten grams o f s o i l were

added to K j e l d a h l f l a s k s and th e o r g a n ic m a t t e r was o x id iz e d by b o i l i n g

119
TABLE 27 .
THE RELATIONSHIP BETWEEN THE AMOUNT OE TOTAL NITROGEN
AND CARBON IN SOILS OE AREA X AND AREA Y

P ercen t
A rea X
H o riz o n

(S tatio n s I - I I )

P e r c e n t N itr o g e n

P e r c e n t Carbon*

IA,
A2
b2

.1 2 5
.0*47
.0*49

2.72S
1.118
.818

2 1 .8 2 : 1
23 .79 : 1
1 6 .6 9 : 1

XIA-i
a2
bI

.1 1 3
.0*4*4
. 0*41

1.9 91
.818
• 76*4

1 7 .6 2 : 1
18 .59 : 1
I 8 .6 3 : 1

.*419

s . 237

117.1*4 : 1

A re a Y

C a rb o n -N itro g e n R a t io

(S ta tio n s III-IV )

IIIA 1
Ap

.133
.0 7 2
.0 60

3 .0 8 2
1.36>4.95*4

2 3 .1 7 : 1
18.9*4 : 1
15 .90 : 1

IVAn
a2
b2

.1 2 1
.05*4
.055

1.909
1 .0 3 6
.873

15.7S : 1
1 9 .1 8 : 1
1 5 .87 : 1

.*495

9.21S

1 0 8 .S*4 : 1

* D e riv e d from e q u a ti o n :

T o tal

C +

Atomic w e ig h t c arb on _________
M o le c u la r w e ig h t c arb o n d io x id e

O2 ——>*

T o tals

C02
12.01

W .o T

z

.272s X ^C0 2

”

p e r c e n t c arbo n

120
F ig .

20.

A COMPARISON OF THE CAHBON-NITROGEN RELATIONSHIP
OF SOILS IN THE AREA OF GOOD HEIGHT GROWTH v a THE
AREA OF POOR HEIGHT GROWTH

|

|

-

C arbon
N itro g e n

X
2 .5

1 9 .4 :1

1 9 .7 :1

X

Good H e i g h t
G r o w th

Y

P oor H e ig h t
G r o w th

2.0

P er­
cent
1 .5
Y

1 9 .0 :1
X

1.0

.

2 1 2:1

Y
X
1 7 .7 rl

.5

S o il H o riz o n

1 5 .8 :1

121

w ith s u l f u r i c a c id .

A p p r o p r i a t e c a t a l y s t s were added t o h a s t e n o x i d a t i o n .

A f t e r d i g e s t i o n and c o o l i n g , an e x c e s s o f sodium h y d ro x id e was added and
t h e ammonia was d i s t i l l e d i n t o s t a n d a r d a c i d .

The p e r c e n t t o t a l n i t r o g e n

th u s o b t a i n e d i n c l u d e s t h e ammoniacs.l and c e r t a i n n i t r a t e forms o f
n itro g e n th a t are p re s e n t.
The p e r c e n t o f c a rb o n was d e r i v e d from th e o r g a n ic m a t t e r d e te r m i­
n a tio n s.

The p e r c e n t c a rb o n d io x id e o b ta in e d in th e d ry com bustion

method i s c o n v e r t e d to p e r c e n t c arb o n by m u l t i p l y i n g each d e t e r m i n a t i o n
by th e f a c t o r .2 7 2 8 .

R e s u l t s of t h e s e c a l c u l a t i o n s a r e p r e s e n t e d in

T a b le 27D iscu ssio n of R e su lts
The change o f n i t r o g e n in combined complex forms to t h e a v a i l a b l e
s o i l n i t r o g e n i s a b i o l o g i c a l p r o c e s s in f l u e n c e d by many f a c t o r s .

From

an e c o l o g i c a l s t a n d p o i n t t h e c a r b o n - n i t r o g e n r a t i o o f s o i l s i s in f l u e n c e d
by s o i l f e r t i l i t y and s ta n d c o m p o s itio n .

F o r f o r e s t t r e e s p e c i e s , v e ry

l i t t l e n i t r o g e n i s l i b e r a t e d as th e n i t r a l e form u n t i l th e c a r b o n n i t r o g e n r a t i o h as narro w ed as a r e s u l t of d e c o m p o s itio n .

An in d e x to

th e d e g r e e o f r e l e a s e of n i t r o g e n was o b ta in e d in t h i s i n v e s t i g a t i o n by
u t i l i z i n g th e carb o n -n itro g e n r a t i o .

The p e r c e n t o f b o th carbo n and

n i t r o g e n i s h i g h e r in th e a r e a of p o o r h e i g h t grow th th an in th e a r e a of
good h e i g h t g ro w th .

C o n s e q u e n tly , th e C/ltf r a t i o is more narrow in A rea Y,

i n d i c a t i n g g r e a t e r d e c o m p o s itio n and re le a .s e of th e n i t r a t e form of
n itro g e n .

The d i f f e r e n c e s in th e C/U r a t i o a r e no t marked betw een a r e a s .

These r e s u l t s d i s c l o s e t h a t th e l e s s dense s i t e (A rea Y) w ith a h i g h e r
c o n t e n t o f o r g a n ic m a t t e r w i l l r e l e a s e more n i t r o g e n th a n th e d e n s e r Area X.
At any g i v e n tim e th e amount of a v a i l a b l e n i t r o g e n w i l l f l u c t u a t e c o n s i d e r a b l y .

122

S in c e a d e t e r m i n a t i o n o f t o t a l n i t r o g e n in c lu d e s more t h a n one form o f
n itro g e n ,

i t i s n o t p o s s i b l e to d i f f e r e n t i a t e th e ammoniacal from th e

n i t r a t e fo rm s i n t h i s d e t e r m i n a t i o n .

However, a c l o s e a p p ro x im a tio n o f

t h e n i t r o g e n c o n t e n t and i t s a v a i l a b i l i t y w i l l be i n v e s t i g a t e d u n d er th e
m i c r o b i o l o g i c a l , p h a se o f th e s tu d y .

TABLE 28.
ANALYSIS OF VARIANCE FOR TOTAL NITROGEN CONTENT CF SOILS IN AREA X v s . AREA Y
P ercent
B a s i s : 12 sam ples ( i n d u p l i c a t e )

A*-

U.

S ource

D egrees o f Freedom

T otal
X vs Y
E rro r

3
1
2

T o tal
X vs Y
E rror
T o tal
X vs Y
E rror

Sum o f Squares

Mean Square

F

.0030
.0005
.0025

.0005
.0 0 1 2

.k2

3
1
2

. 00^5
.OO35
.0010

.0035
.0005

.70

3
1
2

.0 0 2
.001
.0 01

.0 0 1
.0 005

2 .0 0

Cat io n-E xchange O a p ac ity
E x p e rim e n ta l Method:
S o i l sam ples were ta k e n from f i v e s o i l h o r iz o n s r e p r e s e n t i n g

A rea X and A re a Y a c c o r d in g to th e method o f S c h o lle n b e r g e r and Simons
( X9 U5 ) ,

These s o i l s <»ere a i r - d r i e d and p a s s e d th ro u g h a two mm. s i e v e .

T w e n ty -f iv e grams o f a i r - d r y s o i l were p l a c e d in a 3 00 m i l l i l i t e r f l a s k
and le a c h e d w ith 250 m i l l i l i t e r s of IN ammonium a c e t a t e s o l u t i o n and a g a in
le a c h e d w ith .IN ammonium a c e t a t e .

A f t e r th e s o i l in th e f u n n e l had

f i n i s h e d d r a i n i n g , t h e f u n n e l and m o is t s o i l were w eighed.

The s o i l in

123
TABLE 2 9 .

THE CATION-EXCHANGE CAPACITY, EXCHANGEABLE HYDROGEN, TOTAL BASES,
AM) PERCENT BASE SATURATION OP PIVE SOIL HORIZONS IN AREA X AND AREA Y

A rea X
H o riz o n

Cat ion-E xchange
C a p a c ity
m. e . / 100 gms.

IAi
Ar
BI

S. 20
6 . 0S
1 0 .64

B*

13*?F
.4 4

IIA .

Ai
B2
-3

Exchangeable
Hydrogen*
m . e . / 100 gms.

P e r c e n t Base
S a tu r a tio n * *

T o t a l Bases
m .e. / 100
gms.____

7.5693
5.6152
10.1172
2 . 9S11
1.2177

.6307
.H6Hg
. 522 s
• 33g9
.2223

S . Ho
4 . OS
1.60

6.2.766
5.2573
7 . 6S04
3.6975
1.2799

. 523 ^
. 5^27

.7196
. 3^25
.3201

7 .69
8 .b j
8 .56
9*37
2 0.00

56.96

52.2922

667s

9 9 .9 6

10.33
•6. Si
6.97
17.17

6 .so
6.40

7 .6 9

7.64
4.91
10.20
1 5 .^3

T o t a ls

A rea Y
IIIA .

Ag
2

C1
ITA-,

7.72
1 0 .6 s
11. ss
1 .3 6
.24

6.9066
9.9733
11.0516
1.1264

.813^

10.96
s . 72
S . 2S
6 .Us

s.s4

IO.51H3
s . 1161
7.7754
6.1655
s . 6132

.HH57
.6039
. 50H6
.31H5
. 226s

4 ,o 6
6.92
6.09
H.S5
2.56

7^.92

7 0 .2b2k

913 H

6 5 .7 6

.7067
.828b
.2336
. 236 S

H .

** T o t a l "bases d i v i d e d "by c a t io n -e x c h an g e c a p a c i t y X
* Cat io n -e x c h a n g e c a p a c i t y minus t o t a l b a se s
Notes

100

One m illi g r a m e q u i v a l e n t ( m .e .) d e n o te s th e e q u i v a l e n t
w e ig h t, o r t h e ato m ic w e ig h t d iv id e d by th e v a le n c e .

T o tals

12b

th e f u n n e l was t h e n s lo w ly le a c h e d w i t h 2oO m i l l i l i t e r s o f 10 p e r c e n t
NaCl*

T h is s a l t f i l t r a t e was p l a c e d in a K j e l d s h l f l a s k , tw en ty m i l l i l i ­

t e r s o f 2N HaOH were ad d ed, and th e n d i s t i l l e d i n t o f i f t y m i l l i l i t e r s of
^ p e r c e n t "boric a c i d s o l u t i o n *

The d i s t i l l a t e was th e n t i t r a t e d w ith

0.1N HC1 u s in g h ro m c re s o l g re e n a s an i n d i c a t o r *

From th e s e d e te r m i­

n a t i o n s th e m i l l i e q u i v a l e n t s o f a d s o rb e d ammonia, p e r t w e n t y - f i v e grams
o f s o i l were c a l c u l a t e d and th e n c o n v e r te d t o a d so rb e d ba,ses p e r 100 grams
of s o il.

The c a t ion—exchange c a p a c i t y in terms o f m i l l i e q u i v a l e n t s p e r

100 grams o f s o i l i s p r e s e n t e d in T able 29*
D is c u s s i o n of R e s u l t s
The c a ti o n - e x c h a n g e c a p a c i t y o f s o i l s i s l a r g e l y a f u n c t i o n o f th e
k in d s and amounts o f c o l l o i d a l m a t e r i a l and th e t o t a l b a s e s p r e s e n t .

This

p r o p e r t y i s u n d o u b te d ly th e most im p o rta n t c h a r a c t e r i s t i c o f c o l l o i d a l
c la y .

I t i s im p o r ta n t to r e c o g n iz e t h a t th e exchange of c a t i o n s i s a s s o ­

c i a t e d w i t h t h e c o l l o i d a l m a t e r i a l and t h i s a d s o r p t i o n and d is p la c e m e n t
of io n s i s im p o r ta n t in s u p p ly in g t h e n e c e s s a r y b a s e s to p l a n t s .

The

c a t io n -e x c h a n g e r e a c t i o n is r a p i d and r e v e r s i b l e , and r e p r e s e n t s th e
c a p a c i t y of s o i l c o l l o i d s f o r h o ld in g c a t i o n s .

I f th e exchange c a p a c i t y

is s a t i s f i e d by m e t a l l i c c a t i o n s , th e s o i l i s c o n s id e r e d t o be b a s e s a tu ra te d .

However, in f o r e s t s o i l s of humid r e g io n s t h i s c o n d i t i o n i s

r a r e , s i n c e th e b a s e s a r e c o n t i n u a l l y b e in g r e p l a c e d by hydrogen ions and
th e s o i l c o l l o i d s te n d to be b a s e - u n s a t u r a t e d .
The r e s u l t s o b t a i n e d by s o i l h o r iz o n in Column 1, T able 29

re v e als

th e c l o s e r e l a t i o n s h i p o f c a t ion -exchan ge c a p a c i t y to th e amount of f i n e
c la y o r e s e n t.

T h is r e l a t i o n i s most marked in Area X where

f i n e c l a y c o n t e n t and c a t io n -e x c h an g e c a n - c i t y a r e found in

th e h i g h e s t
th e B2 h o r i z o n .

125

The h i g h e s t i n d i v i d u a l c a t i o n exchange v a lu e i s found in t h e
o f A re a Y*

h o r iz o n

An a n a l y s i s o f v a r i a n c e r e v e a l s t h a t no s i g n i f i c a n t s t a t i s ­

t i c a l d i f f e r e n c e i s fo u n d betw een A rea X and A rea Y, a lth o u g h d i f f e r e n c e s
in th e A^ h o r iz o n c l o s e l y a p p ro a c h e s th e f i v e p e r c e n t s i g n i f i c a n t l e v e l .
The p r e s e n t i n v e s t i g a t i o n shows d e f i n i t e l y t h a t th e c a t io n -e x c h an g e
c a p a c i t y i s more c l o s e l y r e l a t e d to t h e in o r g a n ic c o l l o i d s th a n to th e
o r g a n i c c o l l o i d s , as e v id e n c e d by t h e f i n e c l a y c o n te n t o f i n d i v i d u a l
h o riz o n s *

5.

T o t a l B ases and P e r c e n t B ase S a t u r a t i o n
E x p e rim e n ta l Method:
U t i l i z i n g th e same sam pling p ro c e d u re a s f o r th e c a t io n -e x c h an g e

c a p a c i t y d e t e r m i n a t i o n s , t w e n t y - f i v e grams of a i r - d r y s o i l were le a c h e d
w i t h IK and *1K ammonium a c e t a t e .
r a t e d t o d ry n e s s on a h o t p l a t e .

T h is f i l t r a t e was c o l l e c t e d and evapo­
The r e s i d u e was t r a n s f e r r e d to a

p o r c e l a i n e v a p o r a t i n g d i s h and i g n i t e d o v er a Meker b u r n e r .

A f t e r c o o lin g ,

a c a l c u l a t e d e x c e s s o f .2U HC1 was added and th e s o l u t i o n b a c k - t i t r a t e d
w ith 0,1K HaOK.

From t h e s e d e t e r m i n a t i o n s th e m i l l i e q u i v a l e n t s of s o i l

b a s e s p e r 100 grams o f s o i l were c a l c u l a t e d .

To d e te rm in e th e p e r c e n t

b a s e s a t u r a t i o n sim p ly d iv id e th e t o t a l b a se s o b ta in e d by th e c a t i o n exchange c a p a c i t y .

The c o n te n t o f e x ch a n g e ab le hydrogen p l u s th e c o n te n t

of e x c h a n g e a b le m e t a l l i c c a t i o n s is e q u a l to th e t o t a l c a t io n -exchan ge
c ap a c ity .

C o n v e rs e ly , by s u b t r a c t i n g th e t o t a l b a se exchange from th e

t o t a l c a t io n -e x c h a n g e c a p a c i t y , th e ex ch an g eab le hydrogen is o b t a i n e d .
The p e r c e n t ba.se s a t u r a t i o n of a s o i l

is th e d e g re e to w hich th e a d s o r b in g

s u r f a c e o f s o i l c o l l o i d s is s a t u r a t e d w ith m e t a l l i c c a t i o n s .

This s o i l

p r o p e r t y , b e in g a f u n c t i o n of th e t o t a l b a s e s and c a tio n - e x c n a n g e c a p a c i t y

126

i s v e r y i m p o r t a n t , s i n c e i t d e te r m in e s i n p a r t th e a v a i l a b i l i t y of th e
v a r i o u s ' b a s e s to p l a n t s .
R e s u l t s o f t h i s i n v e s t i g a t i o n show t h a t th e h i g h e s t i n d i v i d u a l ba.se
s a t u r a t i o n e x i s t s in th e

h o r iz o n o f A rea X.

I f in d iv id u a l s o il h o ri­

zons a r e c o n s i d e r e d w ith r e f e r e n c e to b a se s a t u r a t i o n , th e v a r i a t i o n
betw een A rea X and A rea Y i s n o t e x tre m e .
( T a b le 33)

An a n a l y s i s o f v a r i a n c e

p e r c e n t b a se s a t u r a t i o n shows a s i g n i f i c a n t d i f f e r e n c e a t

f i v e p e r c e n t betw een A rea X and A rea Y a t th e C-^ h o r i z o n ; t h i s i s th e
o n ly s t a t i s t i c a l l y s i g n i f i c a n t s o i l p r o p e r t y of th e f o u r f a c t o r s h e r e
stu d ie d .
I n o r d e r to show t h e r e l a t i o n s h i p of t h e s e v a l u e s , th e combined
d a t a a r e p r e s e n t e d in T ab le 29.

I t i s i n t e r e s t i n g to n o te th e combined

t o t a l s f o r t h e s e f o u r s o i l p r o p e r t i e s an d how t h e s e p r o f i l e t o t a l s r e l a t e
to th e s o i l ty p e u n d e r i n v e s t i g a t i o n .

The g r e a t e s t t o t a l c a tio n -e x c h a n g e

c a p a c i t y e x i s t s i n A rea Y (p o o r h e i g h t g ro w th ) .

There i s a v e ry c lo s e

r e l a t i o n s h i p h e r e to t h e amount o f f i n e c l a y e x i s t i n g in t h i s s o i l ty p e ,
b o th a s to i n d i v i d u a l h o r iz o n s and t o t a l p r o f i l e .
e x c h a n g e a b le hydrogen i s fo un d in Area Y a l s o .

The g r e a t e s t t o t a l

This r e v e a l s th e c l o s e

r e l a t i o n s h i p of t h e pH v a lu e s o b t a i n e d f o r th e same s o i l s , s i n c e Area Y
shows a s l i g h t l y g r e a t e r a c i d i t y th a n A rea X, when a l l h o r iz o n s a r e
averaged.

T o t a l b a s e c o n t e n t does n o t d i f f e r much in comparing Area X

w ith A re a Y; a s l i g h t l y l a r g e r t o t a l b a se c o n t e n t e x i s t s in Area. Y b u t
t h i s d if f e r e n c e is i n s i g n i f i c a n t .

The l a s t s o i l p r o p e r t y , t h e p e r c e n t

b a s e s a t u r a t i o n , r e v e a l s a l a r g e t o t a l p r o f i l e d i f f e r e n c e betw een A rea X
and A re a Y.

A lth o u g h th e t o t a l d i f f e r e n c e i s i n s i g n i f i c a n t s t a t i s t i c a l l y ,

e x c e p t a t th e C-j_ h o r i z o n , th e p e r c e n t b a se s a t u r a t i o n i s d e f i n i t e l y more

127

TABLE 3 0 .
ANALYSIS OF VARIANCE FOR CATI ON-EXCHANGE CAPACITY POP GOOD HEIGHT
GROWTH (AREA X) v s . POOR HEIGHT GROWTH (AREA Y)

H o riz o n
A1

A?

Bg

B3
j

°1

S ource

M i l l i e q u i v a l e n t s p e r 100 grams s o i l
D egrees o f Freedom Sum o f S qu ares Mean Square

P

T o tal
X vs Y
E rro r

3
1
2

3-7S
3 .3 9
•39

3-39
.19

17 .8

T o tal
X vs Y
E rro r

3
1
2

1 3 .9 ^
11.97
1 .9 7

11.97
.98

12 .2

T o tal
X vs Y
E rror

3
l
2

9.29
.31
S . 98

.31
4 .4 9

.069

T o tal
X vs Y
E rror

3
l
2

1 3 .4 4
.05
1 3 .3 9

.05
6 .6 9

.007

T otal
X vs Y
E rror

3
1
2

4 7 .5 0
g .4 i
3 9.0 9

S .4 l
10.54

• ^3

TABLE 31 .
ANALYSIS OP VARIANCE POR EXCHANGEABLE HYDROGEN FOR GOOD HEIGHT
GROWTH (AREA X) v s . POOR HEIGHT GROWTH (AREA Y)
M i l l i e q u i v a l e n t s p e r 100 grams s o i l
Mean Square
An

A2

B.

T o tal
X vs Y
E rro r

3
1
2

10.51
3.19
7.32

3 .6 6

T otal
X vs Y
E rror

3
1
2

27.19
14. 4S
12.71

l 4 . 4g
6.35

T o tal
X vs Y
E rror

3
1
2

s . 61

T o tal
X vs Y
E rror

3
1
2

T o tal
X vs Y
E rror

3
1
2

3.19

.26

.2 6

s . 35

4.17

13.00
.09
12.91
46.40
9.33
37.07

F

.87

2.2S

.0 6

.09
6 .4 5

.01

9.33
18.53

.50

128

ta b le 32.
ANALYSIS OF VARIANCE FOR TOTAL BASES FOR GOOD HEIGHT
GROWTH (AREA X) v s . POOR HEIGHT GROWTH (AREA Y)

M i l l i e q u i v a l e n t s p e r 100 grams s o i l
H o riz o n

S ource

D eg rees o f Freedom

A1

T o tal
X vs Y
E rror

3
1
2

T o tal
X vs Y
E rro r

A2

Cm

BO
d

B3
j

C

Mean Square

F

.0759
.0100
.0659

.0100
.0329

• 33

3
1
2

.0373
.0 300
.0073

.O3 OO
.OO36

S . 33

T otal
X vs Y
E rror

3
1
2

.077S
.0100
.067 8

.010 0
.0339

.3 *

T o tal
X vs Y
E rror

3
1
2

.0090
.0050
. 00 H0

.0 05 0
.0 0 2 0

2 .3 0

T o tal
X vs Y
E rror

3
1
2

.0 113
.0062
.0051

.0 0 6 2
.0 0 2 5

2 .H 8

Sum o f Squ ares

TABLE 3 3 .
ANALYSIS OF VARIANCE FOR PERCENT BASE SATURATION FOR GOOD HEIGHT
GROWTH (ARM X) vs-. POOR HEIGHT GROWTH (AREA Y)

H o riz o n

2

b2

B,
3

C-,1

Source

P ercent
D egrees o f Freedom Sura o f Squares

T o tal
X vs Y
E rror

3
1
2

2 1 .0 9
.15

T o ta l
X vs Y
E rror

3
1
2

2 .0 6
1 .6 6

T otal
X vs Y
E rror

Mean Square

F

.15
1 0 . H7

.0 1

.Ho

1*66
.2 0

s . 30

3
1
2

7.09
.oH
7 .0 5

.oH
3 .5 2

.0 1

T otal
X vs Y
E rror

3
1
2

77.73
1 .5 0
7 6 .2 3

1 .5 0
3 S .il

.03

T o tal
X vs Y
E rror

3
1
2

282.82
2 7 0 .1 0
1 3 .7 2

2 7 0 .1 0
6 .s 6

* S ig n if ic a n t a t

2 0 .9H

39.37*

129

c l o s e l y c o r r e la te d w ith th e area o f good h e ig h t growth than w ith th e area
o f poor h e ig h t grow th.

An a n a ly s is o f v a r ia n c e of th e fou r s o i l p r o p e r tie s

examined i s p r e se n te d in support o f th e p r e se n t d is c u s s io n .

These r e la t io n ­

s h ip s w i l l he d is c u s s e d fu r th e r when th e com plete a n a ly s is o f a l l chem ical edaphie f a c t o r s i s c o n sid e r e d .

S.

I n d iv id u a l F u tr ie n t Elements

(Ca, Mg, P, K, ¥ a , F e, Mn)

E xperim ental Method:
A d e te r m in a tio n o f th e amount o f calcium , magnesium, and sodium
was o b ta in e d by u se o f th e flam e photom eter.

T ransm ission v a lu e s fo r each

n u tr ie n t elem ent were p lo t t e d a g a in s t standard v a lu e s fo r th a t elem en t, and
th e corresp on d in g n u tr ie n t v a lu e was read from th e standard cu rve.

The

p a r ts p er m illio n thus ob tain ed were con verted to m illie q u iv a le n t s per 100
grams o f s o i l u sin g ap p rop riate co n v ersio n v a lu e s .

A n a ly sis o f v a ria n ce fo r

each elem ent was based upon p a r ts per m illio n o f th a t n u tr ie n t e x is t in g in
th e s o i l .
The amount o f a v a ila b le phosphorus and exchangeable potassium was
o b ta in e d by th e c o lo r im e tr ic method, u t i l i z i n g th e Lumetron P h o t o - e le c t r ic
c o lo r im e te r .

Ammonium f lu o r id e was used as the e x tr a c tin g agent fo r

phosphorus and ammonium molybdate as the reducing a g en t.

For pota.ssium ,

th e s o i l s were e x tr a c te d w ith sodium n it r a t e and reduced w ith sodium
c o b a lt i n i t r i t e s o lu t io n .
The amount o f a v a ila b le iron and manganese was ob tain ed by e x tr a c tin g
the s o i l s w ith h y d ro c h lo r ic a c id .

To determ ine the manganese c o n te n t,

sodium b ism u th ate was used as an o x id iz in g a g en t.

For a v a ila b le ir o n ,

130

F ig ♦ 2 1 .

A. COMPARISON OF TOTAL. INDIVIDUAL NUTRIENT ELEMENT:
EXPRESSED AS A PERCENT OF TOTAL- PROFILE CONTENT

Good H e i g h t G r o w th ( A r e a X)
40

-

30

-

20

-

10

-

Per
cent

Ca

Mg

P

K

Na

Fe

Mn

Fe

Mn

N u t r i e n t E lem en t

P o o r H e i g h t G r o w th ( A r e a Y)
40

-

30
Per
cent

»

20

-I

10

-

Ca

Mg

P

K

N u t r i e n t E le m e n t

Na

131

h y d ro x y l amine h y d r o c h l o r i d e was u s e d w ith 0 —p h e n a n t h r o l i n e to keep th e
i r o n in th e f e r r o u s s t a t e .
A f t e r c o n v e r t i n g t h e s e e lem en ts to m i l l i e q u i v a l e n t s p e r 100 grams of
s o i l , t h e p e r c e n t a g e o f th e t o t a l e le m e n ts p r e s e n t was d e te rm in e d f o r each
n u trie n t.
F o r th e sake o f b r e v i t y , th e d e t a i l e d p r o c e d u re f o r o b t a i n i n g each
elem en t i s o m i t t e d ; s t a n d a r d c u rv e s f o r t h e same elem ents a r e n o t in c lu d e d .
A summary o f a l l n u t r i e n t e le m e n ts , o c c u r r i n g by s o i l h o r iz o n in each
s a m p lin g a r e a i s g iv e n i n T a b le 3 ^ .

The r e l a t i o n s h i p o f i n d i v i d u a l e lem en ts

fo u n d in t h e a r e a o f good h e i g h t gro w th and p o o r h e i g h t gro w th w i l l now be
d i s c u s s e d , f o llo w e d by a g e n e r a l summary o f th e e d a p h ic -c h e m ic a l im p lic a ­
tio n s.

A l l p e r c e n t a g e f i g u r e s g iv e n f o r each elem ent r e f e r to th e p e r c e n t

o f t o t a l n u t r i e n t s t h a t were i n v e s t i g a t e d f o r combined t o t a l profiles.-*-®
Calcium r e l a t i o n s
S in c e c a lc iu m e x e r t s a p ro fo u n d i n f l u e n c e upon th e p h y s i c a l , c h em ica l,
and b i o l o g i c a l p r o p e r t i e s o f s o i l s ,
re la tio n s.

i t i s im p o rta n t in f o r e s t s o i l f e r t i l i t y

Combined d a t a p u b l i s h e d by s e v e r a l i n v e s t i g a t o r s , su ch as

K i t t r e d g e (1933) » h u n t (1935) » nnd C handler ( 1 9 ^ ) have shown t h a t th e
c a lc iu m c o n te n t o f f r e s h l y f a l l e n l e a v e s o f t u l i p p o p l a r i s a p p ro x im a te ly
2 .9 6 p e r c e n t.

T h is v a l u e was s u r p a s s e d o n ly by basswood, when a c o n s id e r ­

a t i o n o f t w e n ty - f o u r t r e e s p e c i e s were i n v e s t i g a t e d f o r c alc iu m c o n te n t of
fre s h le av e s.

I t h a s been shown t h a t a h ig h c o n te n t of c a lc iu m in f o r e s t

1 0 . S in c e o t h e r n u t r i e n t e le m e n ts such as b o ro n , z in c , s u l f u r , and
c o p p e r may be p r e s e n t in th e s o i l in v e ry sm a ll q u a n t i t y , th e
p e r c e n t o f t o t a d n u t r i e n t s and b a se s a t u r a t i o n i s p r o b a b ly
s l i g h t l y h i g h e r th a n p e r c e n ta g e s g iv e n in T able 3^*

132
TABLE 3 4 .
THE NUTRIENT CONTMT OP SOILS BY SOIL HORIZON AND TOTAL PROFILE
IN AREA X AND AREA Y

M i l l i e q u i v a l e n t s p e r 100 grams s o i l
A re a X
N u t r i e n t Element
H o riz o n
IA1
A2
b2

B3
11 At
a2
b|

B3
Ci

Ca
•3375
.1925
.1975
.0575
.0 2 0 0

Mg
.1229
.1024
.1065
.0918
.0893

P
.0257
.0737
.0873
.0446
.0 3 6 8

K
.0 5 6 2
.0 3 0 6
.075^
.0664
.0383

Na
.0327
.0205
.0135
.0629
.0197

Fe
.0193
.0247
.0412
.0143
.0 1 6 8

Mn
. 036 U
.0204
.0014
.0014
.0014

T o ta l
.63 07
.4648
.52 88
•33s 9
.2223

.1 9 0 0
.2 2 0 0
.2950
.0 6 0 0
.0*400

.1 3 1 1
.1 3 1 1
.1303
.1 2 2 1
.12 29

.0485
.0970
.1087
.0 9 3 2
.0543

.0613
.0 3 3 2
.0997
.0639
.0485

.0428
.0 2 6 2
.0598
.0187
.0441

.0154
.0 3 0 1
.0247
.0 2 3 2
.0089

.0343
.0 0 5 1

.o o i4
.0014
.o o i4

.5234
.5427
.7196
•3S25
.3201

1.6100

1.1504

. 669s

*5735

.3 ^ 9

.2186

.1046

4.6678

.0157
.0483
.o4 s3
.0136
.0096

.0481
.0014
.0014
.0014
.o o i4

.8134
.7067
.8284
.2336
.2368

.016s
.0412
.0530
.0232
.0129

.0145
.o o i4
.0014
.0102
.o o i4

.4457
.6039
.5046
.3145
.2268

.2826

.0826

U . 913 U

T otal

A rea Y

IIIA,

.5250

.1U34

.03^9
.0485

Ap

-U075

-1229

b2

.U700

. 1 U3 U

.0370

.0332

.0306 .0157
.0664 .0117
.1074 .0209
.0511 .0192

B,

.0250

.0901

Ci

.0 3 7 5

.0 9 0 1

.oH'g5

.0332

.0165

IVA,
Ap

.1900
.3200

.1311
.1377

.0466
.0466

. 03^5
. 03 S3

.0122
.0187

b2
B,

.1 6 7 5

-1352

.O36S

.075^ .0353

Ci

. 0 ^x5
.0225
2.2065

.1295
.12!+5
I . 2U79

.0407

.0174
.3882

.0511

.0281
. 51bl

.0183
.0200

.1885

T o ta l

133

tre e l i t t e r

i n c r e a s e s t h e amount o f e x c h a n g e ab le c alc iu m in t h e s o i l .

T h ere i s a d i s t i n c t te n d e n c y f o r th e n u t r i e n t c a lc iu m to he c o n c e n t r a t e d
in th e up perm ost l a y e r s , and th e n d i s t r i b u t e d v e r t i c a l l y th ro u g h o u t th e
h o r i z o n a c c o r d in g to th e d e g re e o f l e a c h i n g and r o o t p e n e t r a t i o n .
The r e s u l t s o f t h i s i n v e s t i g a t i o n show t h a t c alciu m i s p r e s e n t in
h i g h e r c o n c e n t r a t i o n th a n any o f th e re m a in in g s i x n u t r i e n t e le m e n ts ,
w i t h t h e e x c e p t i o n o f h y dro gen.

I n A rea X, t h e calc iu m r e p r e s e n t s 3^*5

p e r c e n t o f th e t o t a l n u t r i e n t s fo u n d ; in A rea Y t h e calc iu m r e p r e s e n t s
M+.9 p e r c e n t o f th e t o t a l n u t r i e n t s u p p ly .

The v e r t i c a l d i s t r i b u t i o n o f

c a lc iu m i n t h e p r o f i l e o f A rea X shows a d i s t i n c t d e c r e a s e in amount from
u p p e r to lo w er h o r i z o n s , b u t a t S t a t i o n I o n ly .

At S t a t i o n I I , th e

c a lc iu m i s h i g h e s t a t t h e Bg h o r i z o n .

F o r A rea Y, a t S t a t i o n I I I , th e

c a lc iu m i s g r e a t e s t a t th e A-^ h o r i z o n .

At S t a t i o n IV, th e c a lc iu m i s

h ig h e st a t th e ^

h o rizo n .

Thus, th e v e r t i c a l d i s t r i b u t i o n o f calcium

in t h e s e p r o f i l e s f o ll o w s no s e t p a t t e r n , b u t v a r i e s c o n s i d e r a b l y .

How­

e v e r , t h e d i s t r i b u t i o n o f c alc iu m in i n d i v i d u a l h o r iz o n s shows a c lo s e
c o r r e l a t i o n to t h e t o t a l b a se c o n te n t o f th e same h o r i z o n s .

A g re a te r

t o t a l p r o f i l e c a lc iu m c o n te n t e x i s t s in A rea Y, though th e amount i s n o t
s i g n i f i c a n t l y g r e a t e r th a n A rea X.

T h is f a c t i s n o te w o rth y , s i n c e th e

amount o f f r e s h l i t t e r in A rea X i s n e a r l y tw ic e th e amount in A rea Y.
An a n a l y s i s o f v a r i a n c e (T ab le 35) e x h i b i t s no s t a t i s t i c a l l y s i g n i f i c a n t
d i f f e r e n c e in th e amount o f a v a i l a b l e calc iu m between Area X and A rea Y.
However, th e F - v a l u e d e n o te s th e g r e a t e s t d i f f e r e n c e o c c u r r in g a t th e Ag
h o riz o n .

I n g e n e r a l , t h e g r e a t e s t d i f f e r e n c e in c alc iu m c o n te n t is

r e s t r i c t e d to t h e s u r f a c e h o r i z o n s , when comparing th e two s i t e s .

13^
TABLE 35.
ANALYSIS OF VARIANCE FOR CONTENT OF AVAILABLE CALCIUM BY SOIL HORIZON IN
AREA X v s . AREA Y
P a r t s p e r m i l l i o n ( p . p .m . ) s o i l
D eg rees o f Freedom Sum o f S qu ares Mean Square

H o riz o n

S ource

h.

T o tal
X vs Y
E rro r

3
1
2

U0 2 3 .1 9
3 5 1 .5 6
3671.63

3 5 1 .5 6
1S35.S1

T o tal
X vs Y
E rror

3
1
2

I I 6 0 . 5O
992.25
l 6 S . 25

9 9 2 .2 5
S^ .1 2

1 1.79

T o tal
X vs Y
E rro r

3
1
2

2 2 3 0 .5 0
2 1 0 .2 5
2 0 2 0 .25

2 1 0 .2 5
1 0 1 0 .1 2

.2 1

T o tal
X vs Y
E rror

3
1
2

3 1.5 S
2 6 .0 1
5 .57

2 6 .0 1
2 .7S

9 .3 6

T otal
X vs Y
E rror

3
1
2

1 2 .5 0
0 .0 0
1 2 .5 0

0 .0 0
6 .2 5

0 .0 0

A2

b2

C

F

.191

TABLE 3 6 .
ANALYSIS OF VARIANCE FOR CONTENT OF AVAILABLE MAGNESIUM BY SOIL HORIZON IN
AREA X v s . AREA Y

H o riz o n

Source
T otal
X vs Y
E rror

Ar

B,

B-

T otal
X vs Y
E rror

P a r ts p e r m illio n (p .p .m .) s o i l
D egrees o f Freedom Sum o f S q uares Mean Square
3

1
2

3

1
2

3.19

I.56
I.63

1.56
.S I

10. ^7
2.72

2.72

7.75

3 .S7

6.50

T o tal
X vs Y
E rror

3

1
2

11.21
6.50
4.71

T otal
X vs Y
E rror

3

IS.U 9

1
2

i s

T o tal
X vs Y
E rror

3
1
2

F

1.92
.70

2 .3 5

2.76

. 37

.12
9.1s

.01

17.25
.02
17.23

.02
s .61

.0 0 2

.12

135

Magnesium r e l a t i o n s
The seco n d h i g h e s t n u t r i e n t elem ent o c c u r r i n g in th e p r o f i l e s o f "both
A re a X and A re a Y i s magnesium.

I n g e n e r a l , magnesium fo llo w s th e same

v e r t i c a l d i s t r i b u t i o n as c a lc iu m , e x ce p t t h a t t h e g r e a t e s t s t a t i s t i c a l
d i f f e r e n c e "between a r e a s i s a t th e B2 h o r iz o n (T a b le 3 6 ) .

The l a r g e r

t o t a l amount o f magnesium ( a s w ith calcium ) o c c u rs in A rea Y.

I n A rea X,

th e t o t a l p r o f i l e c o n t e n t o f magnesium i s 2 ^ .6 p e r c e n t and f o r A rea Y th e
t o t a l c o n ten t is

p e rc en t.

Magnesium, in t h e p r o f i l e s s t u d i e d , shovrs

l i t t l e v a r i a t i o n betw een h o r iz o n s in b o th a r e a s and i s n o t as d i s t i n c t l y r e s t r i c t e d by h o r i z o n a s c a lc iu m .

I t i s n o te w o rth y t h a t th e combined

calcium -m agnesium c o n t e n t r e p r e s e n t s 59 p e r c e n t and 70 p e r c e n t o f th e
t o t a l n u t r i e n t s p r e s e n t , f o r A rea X and A rea Y r e s p e c t i v e l y .

No s i g n i f i c a n t

F - v a l u e i s fo u n d f o r c o n te n t of a v a i l a b l e magnesium a t any h o r i z o n .
P ho sph oru s r e l a t i o n s
V a rio u s i n v e s t i g a t o r s have em phasized th e im p ortance o f a v a i l a b l e
p h o s p h o ru s t o s o i l p r o d u c t i v i t y .

However, Hennecke (1935) was u n a b le to

e s t a b l i s h any c l e a r r e l a t i o n s h i p betw een th e pho sp h oru s c o n t e n t o f sandy
s o i l s and s i t e q u a l i t y .

The amount o f p ho sp ho rus in s o i l s i s u s u a l l y s m a l l.

The p r e s e n t i n v e s t i g a t i o n r e v e a l s t h a t A rea X has a 1^.3 p e r c e n t t o t a l
p r o f i l e p h o sp h o ru s c o n t e n t as c o n t r a s t e d to a 7*9 p e r c e n t t o t a l p r o f i l e
c o n t e n t in A rea Y.

T h is p e r c e n ta g e d i f f e r e n c e r e p r e s e n t s n e a r l y tw ic e th e

amount o f a v a i l a b l e p h o sp h o ru s in A rea X as t h a t in A rea Y.

The l i g h t e r

s o i l s o f A re a X i n d i c a t e a c o r r e l a t i o n betw een t h e amount of p ho sp h o ru s and
th e f i n e c lay f r a c t i o n .

Thus, in th e Bg h o r iz o n which c o n t a i n s th e g r e a t e s t

f i n e c l a y c o n t e n t , t h e amount o f p hosphorus is h ig h e r th a n in o t h e r h o r iz o n s
o f A re a X.

F o r A re a Y, t h i s r e l a t i o n s h i p i s l e s s marked, and th e ph osph o rus

136

te n d s t o be more e v e n ly d i s t r i b u t e d th ro u g h o u t t h e p r o f i l e , w ith s l i g h t l y
g r e a t e r amounts i n t h e u p p e r h o r i z o n s .

The amount o f a v a i l a b l e ph osphorus

a p p e a r s t o "be more c l o s e l y r e l a t e d to th e c o l l o i d a l c la y th a n to th e
co n ten t of o rg a n ic m a tte r.

The o r g a n ic m a t t e r c o n te n t a p p e a rs to f o ll o w

a d e c r e a s e i n amount from s u r f a c e to s u b s u r f a c e h o r i z o n s .

Prom t h e r e s u l t s

o b t a i n e d , A re a Y a p p e a rs to have more t o t a l pho sph oru s " t i e d - u p " th a n
A re a X, s i n c e t h e amounts o f c o l l o i d a l c l a y and o r g a n ic m a t t e r a r e h i g h e s t
in A re a Y.

An a n a l y s i s of v a r i a n c e (T a b le 37) shows a s i g n i f i c a n t l y

d i f f e r e n t p h o sp h o ru s c o n te n t a t th e 51° l e v e l , f o r th e

h o riz o n .

T his is

f u r t h e r e v id e n c e o f t h e c o r r e l a t i o n betw een th e amount o f p h osph oru s and
th e c o n t e n t of f i n e c o l l o i d a l c l a y in A rea X.
P o ta s s iu m r e l a t i o n s
The amount o f e x ch a n g e ab le s o i l p o ta s s iu m i s u s u a l l y p l e n t i f u l f o r
good t r e e g ro w th , e x c e p t in sandy s o i l s .
o f p o ta s s iu m i n c r e a s e s w ith s o i l d e p th .

Por most s o i l s , th e t o t a l amount
The r e l e a s e o f p o ta ss iu m depends

upon t h e s t a t u s o f th e p o ta s s iu m e q u i l i b r i u m , amount and k in d o f c la y
m a t e r i a l p r e s e n t , and th e p e r c e n t b a se s a t u r a t i o n .
rium i s r a t h e r complex in s o i l s .

The p o ta s s iu m e q u i l i b ­

When p o ta s s iu m i s " f ix e d " i t may be t i e d

up by b i o l o g i c a l f i x a t i o n , tr a p p e d on o r g a n ic m a t t e r c o a t i n g s , f o r c e d in to
t h e c r y s t a l l a t t i c e s t r u c t u r e , o r t i e d up in p o ta s s iu m - lr o n - p h o s p h a t e
com plex es.

Whether p o ta s s iu m i s " f ix e d " o r " r e l e a s e d " depends upon th e

f l u c t u a t i o n o f th e p o ta s s iu m e q u i l i b r i u m .
The p r e s e n t i n v e s t i g a t i o n r e v e a l s a t o t a l p r o f i l e c o n te n t of 12-3
p e r c e n t p o ta s s iu m in A rea X end a 10 .5 p e r c e n t c o n te n t in A rea Y, when
p e r c e n t o f t o t a l n u t r i e n t s i s c o n s id e r e d .

G r e a t e s t amounts o f p o ta s s iu m

o c c u r in t h e B2 h o r i z o n f o r a l l f o u r p r o f i l e s .

In a l l of th e s o i l ty p e s

TABLE 37.

137

ANALYSIS OF VARIANCE FOR CONTENT OF AVAILABLE INORGANIC PHOSPHORUS IN
AREA X v s . AREA Y

H o riz o n
KX

a2

B2

b3
c

S ou rce

P a r t s p e r m i l l i o n ( p .n .m . ) s o i l
D eg rees o f Freedom Sum o f S quares

Mean Square

F

T o tal
X vs Y
E rro r

3
1
2

3 .6 2
. 11+

2 . 4g

.14
1 .2 4

.1 1 2

T o tal
X vs Y
E rro r

3
1
2

i s . 96
1 6 .0 0
2 .9 6

1 6 .0 0
1.4S

10. SO

T o tal
X vs Y
E rror

3
1
2

4 l .9 S
3 9 .56
2 . 1+2

3 9 .5 6
1 .2 1

3 2 . 69 *

T o tal
X vs Y
E rror

3
1
2

2 3 .6 3
1 0 . S3
1 2 . SO

T otal
X vs Y
E rro r

3
1
2

S . 1*3
1 .6 9
6 .7 4

1 0 . S3

6 . 4o

1 .6 9

1 .6 9
3 .3 7

.50

* S i g n i f i c a n t a t 5^
TABLE 3S.
ANALYSIS OF VARIANCE FOR CONTENT OF EXCHANGEABLE POTASSIUM BY SOIL HORIZON
IN AREA X v s . AREA Y
P a r t s p e r m i l l i o n ( p .p .m .) s o i l
D egrees of Freedom Sum o f Squares Mean Square

H o riz o n

Source

A1X

T o tal
X vs Y
E rror

3

k 20

CL

3

Cl1

F

2

10S.21+
1 0 5 .0 6
3.1S

IO5.O6
1 .5 9

6 6 . 07 *

T o tal
X vs Y
E rror

3
1
2

1 2 5 .0 0
6 4 .00
6 1 .0 0

64.oo
3 0 .5 0

2.09

T otal
X vs Y
E rror

3
1
2

125.55
2 .2 5
I 2 3 . 3O

' 2 .2 5
6 1 .6 0

T o tal
X vs Y
E rror

3
1

30.75
30.25
.50

3 0 .2 5
.2 5

T o tal
X vs Y
E rror

3

35.00
2 5 .0 0
1 0 .0 0

2 5 .0 0
5 .0 0

1

2

1

2

** S i g n i f i c a n t a t 51°
* S i g n i f i c a n t a t 5$

1 /®

.036

1 2 1 . 0 0 **

5 .0

133

h e r e i n v e s t i g a t e d , t h e amount o f a v a i l a b l e p o ta s s iu m a p p e a rs to be
c o r r e l a t e d w ith t h e amount of o r g a n ic m a t t e r and t h e calc iu m —p o ta s s iu m
r a t i o o f t h e A-^ and B-^ h o r iz o n s r e s p e c t i v e l y .

An a n a l y s i s o f v a r i a n c e

shows a d e f i n i t e s i g n i f i c a n t d i f f e r e n c e a t th e

l e v e l f o r p o ta s s iu m in

th e A-^ h o r i z o n , and a d i f f e r e n c e a t th e *yjo and 1% l e v e l s f o r p o ta s s iu m in
B-^ h o r i z o n .

Even

th o u g h th e P - v a lu e d e n o te s t h i s h o r iz o n d i f f e r e n t i ­

a t i o n , t h e t o t a l c o n te n t betw een

A rea X and A rea

Y i s no t s i g n i f i c a n t .

Sodium r e l a t i o n s
Sodium i s a common c o n s t i t u e n t of p l a n t s and in f l u e n c e s t h e c a t i o n i n t e r r e l a t i o n s h i p in th e p l a n t .

I t i s n o t d e f i n i t e l y known to be e s s e n t i a l

f o r p l a n t g ro w th , e x c e p t f o r c e r t a i n p l a n t s .
As w ith p o ta s s iu m , th e g r e a t e s t d i f f e r e n c e in th e amounts o f sodium
was fo u n d in th e A-j_ h o r iz o n in comparing A rea X w ith A rea Y.

In A rea X,

sodium r e p r e s e n t s 7*3

p e r c e n t of t h e t o t a l b a s e s

p r e s e n t and in A rea Y

sodium r e p r e s e n t s 3*$

p e r c e n t o f th e t o t a l b a se s

p re se n t.

An a n a l y s i s of

v a r i a n c e shows t h e d i f f e r e n c e in amount o f e x ch ang eab le sodium to be
s i g n i f i c a n t a t th e 5$ l e v e l in th e A^ h o r i z o n .

Here a g a in , th e amount of

sodium a p p e a rs to be r e l a t e d to th e c a t io n -ex ch an g e c a p a c i t y , th e amount
o f o r g a n ic m a t t e r , and t h e p o ta ss iu m -so d iu m r e l a t i o n s h i p , f o r th e s o i l
ty p e s u n d e r i n v e s t i g a t i o n .
Iron re la tio n s
The amount o f a v a i l a b l e i r o n p r e s e n t in s o i l s is o f t e n dep end en t upon
t h e p a r e n t m a t e r i a l and th e c l i m a t i c c o n d i t i o n s -under which th e s o i l s
d e v e lo p e d .

R e s u l t s o f t h i s i n v e s t i g a t i o n show a r a t h e r d i s t i n c t accumula­

t i o n o f t h i s n u t r i e n t in th e B h o r i z o n , p o s s i b l y due to le a c h i n g e f f e c t s .
A v e r y c l o s e r e l a t i o n s h i p seems to e x i s t between th e smount o f a v a i l a b l e

TABLE 3 9 .

139

ANALYSIS OF VARIANCE FOR CONTENT OF EXCHANGEABLE SODIUM BY SOIL HORIZON
IN AREA X v s . AREA Y

H o riz o n
A*1

a2

b2

b✓
3

ci

S ou rce

P a r t s p e r m i l l i o n ( p . p . m .) s o i l
D egrees o f Freedom Sum o f S q uares

32.67
29.70
2.97

T o tal
X vs Y
E rro r

3

T o tal
X vs Y
E rror

3

T o tal
X vs Y
E rror

3

T o tal
X vs Y
E rro r

3

T o tal
X vs Y
E rror

3
1

76.53
25.50
51.03
25 . S6
9.S6

2

16.00

l

2
1

2
1

2
1

2

5 .5 5

3.42
2 .I 3
65 .U3
3 . SO
61.63

Mean Square

29.70
i.4s

F

20 . 07 *

3.42
1.06

3.23

3 . SO
30 . SI

.123

25.50
25.51

1 .0 0

9 .S6
s . 00

1.23

* S i g n i f i c a n t a t 5^
TABLE 40.
ANALYSIS OF VARIANCE FOR CONTENT OF AVAILABLE IRON BV' SOIL HORIZON IN
AREA X v s . AREA Y

H o riz o n
A^l

Ap

B0
2

B?
j

Cl

Source

P a r t s p e r m i l l i o n (p i.p .m .) s o i l
D egrees o f Freedom Sum o f Squares Mean Square

T o tal
X vs Y
E rror

3

T o tal
X vs Y
E rror

3

26.65
23.52

2

T o tal
X vs Y
E rror

3

3.13
35.93
24.50
11.43
6 . 7s

T o tal
X vs Y
E rror
T otal
X vs Y
E rror

1

2
1

1
2

3

.7*

.09
.65

.09
.32

,2S

23.52
I .56

15.0S

24.50
5.71

4.29

.01

.0 1

2

6.77

3.3S

3

3.03

1

1

2

.20
2 . S3

F

.003

.20

1.41

.l4 l

ii+o
TABLE 1+1.
ANALYSIS OP VARIANCE FOR CONTENT OP AVAILABLE MANGANESE BY SOIL HORIZON
IN AREA X vs * AREA Y

P a r ts per m illio n o f s o i l
H orizon

A2

Source

D egrees o f Freedom

Sum o f Squares

Mean Square

F

T o ta l
X vs Y
Error

3
l
2

P - 71
1.21
^■2.R0

2 1 .2 5

T o ta l
X vs Y
Error

3
1
2

I S . 1+3
9 .6 1
g .8 2

9 .6 1
l+.l+l

2.18

T o ta l
X vs Y
Error

3
l
2

H.32
l.S+3
2.39

1.1+3
1.1+4

1 .0 0

1.21
.0 5 6

b2

3

ci

——

i r o n and th e c o l l o i d a l c o n te n t o f th e B2 h o r iz o n .

Under th e a c i d

c o n d i t i o n s o f th e s o i l s h e re s t u d i e d , t h e i r o n i s r e l a t i v e l y s o l u b l e .
A p p a r e n t ly t h e r e i s s u f f i c i e n t a e r a t i o n and d ra in a g e to cau se le a c h in g
o f t h e i r o n i n t o th e B h o r i z o n .

S in c e s o l u b l e iro n i s o f t e n a s s o c i a t e d

w ith a n a e r o b ic c o n d i t i o n s , th e l a r g e r amounts o f t h i s elem ent fou nd in
A rea Y may b e e x p l a i n e d on th e b a s i s of g r e a t e r w a te r - h o ld in g c a p a c i t y
o f t h i s s i t e , l e s s a v a i l a b l e oxygen, or e l s e due to i n c r e a s e d l e a c h in g
from t h e u p p e r h o r i z o n s .

Ares, X r e p r e s e n t s 1+.7 p e r c e n t o f th e t o t a l

n u t r i e n t s s t u d i e d and A rea Y r e p r e s e n t s 5 .S p e r c e n t i r o n c o n te n t o f a l l
bases p re s e n t.

The amount of o r g a n ic m a t t e r does n o t a p p ea r to be

c l o s e l y r e l a t e d to th e ir o n c o n te n t o f any s o i l type i n v e s t i g a t e d , s i n c e
th e g r e a t e s t amount o f ir o n i s fou nd in th e B h o r iz o n .
■ygLriance shows no s i g n i f i c a n t d i f f e r e n c e s betw een a r e a s .

An a n a l y s i s o f

ib i

Manganese r e l a t i o n s
Very l i t t l e

i s known c o n c e rn in g t h e im p ortan ce o f manganese in

th e n u t r i t i o n of f o r e s t t r e e s .

However, th e amounts o f manganese

a b s o r b e d by t r e e s may be c o n s i d e r a b l e , o f t e n e x ce e d in g calc iu m in some
ty p e s o f f o r e s t humus.

I n t h i s s tu d y , t h e manganese e x i s t s in th e s m a l l e s t

amount o f t h e sev e n b a s e s c o n s i d e r e d .

A rea X r e p r e s e n t s 2 . 2 p e r c e n t and

A re a T 1*7 p e r c e n t o f th e t o t a l n u t r i e n t s i n v e s t i g a t e d by t o t a l p r o f i l e .
G r e a t e s t amounts o f manganese a r e fo un d in th e A h o riz o n o f b o th A rea X
and A re a Y.

T h is would te n d to r e l a t e th e amount fou nd w ith th e c o n te n t

o f o r g a n i c m a t t e r , s i n c e low manganese o f t e n i n d i c a t e s low o r g a n ic m a tte r
c o n ten t.

The manganese o c c u r r i n g i n b o th a r e a s seems to f o l l o w th e

t r e n d o f t h e p r o f i l e from s u r f a c e to s u b s u r f a c e h o riz o n s in t h e same
manner a s th e o r g a n i c m a t t e r .

Ho s i g n i f i c a n t d i f f e r e n c e e x i s t s i n th e

manganese c o n t e n t betw een a r e a s .

Ik2
TABLE 42.
A STATISTICAL SUMMARY OE "P" VALUES EOR EDAPHIC-CHEMICAL
CHARACTERISTICS IN AREA X v s . AREA Y
LABORATORY EXPERIMENTS

A1
A verage D ep th 0- 9 "

S o i l H o rizon
a2
b2
9 - i 4«

1^23"

B3
23 - 3 3 "

Cl

33" ■«

V a ria b le In v e s tig a te d :
S o i l A c i d i t y (pH)

*73

2.61

4.25

1.32

2.21

2.

O rg a n ic M a tt e r

.06

1.61

.00

.00

.00

3*

T o t a l N itr o g e n

.42

.70

2.00

---

—

4.

Cat ion-E xch an g e
Capac i t y

17. so

12.20

.069

•

O
O
—
•J

1.

.*3

5-

T o t a l B ases

*33

S . 33

.3*

2.50

2 . 4S

6.

B ase S a t u r a t i o n

.01

s . 30

.01

.03

39 . 37*

7.

E x c hang eab le
Hydrogen

.87

2.2S

.06

.01

.50

S.

A v a i l a b l e Calcium

.191

11.79

.21

9.36

.00

9.

A v a i l a b l e Magnesium

.70

2.76

.01

1.92

.002
.50

.112

1 0 . SO

32. 69*

11. E xchang eab le
P o ta s s iu m

66. 07*

2.09

.036

121.00**

5.00

12. E x c hang eab le
Sodium

20.07*

3*23

.123

1.00

1.23

10. A v a i l a b l e Ph o sph o rus

13* A v a ila b le Iro n

.28

1 5 .OS

4.29

i 4 . A v a ilab le
Manganese

.056

2 .1 s

.00

** S ig n if ic a n t at ifo and 5%
* S ig n if ic a n t at 3%

1.69

.003
1.00

.l4 l

.00

143

Summary and I m p l i c a t i o n o f R e s u l t s
E d ap hic-C hem ical C h a r a c t e r i s t i c s
I n c o n s i d e r i n g th e i m p l i c a t i o n s h r o u gh t o u t by th e r e s u l t s of th e
s o i l - c h e m i c a l d e t e r m i n a t i o n s , i t i s im p o rta n t to r e c o g n iz e t h a t th e
i n t e g r a t i o n o f a l l p o s s i b l e c o n t r i b u t i n g f a c t o r s is n e c e s s a r y .

The

p u r p o s e o f th e p r e s e n t summary i s to p o i n t o u t th o s e f a c t o r s which may
o r may n o t be c o n t r i b u t i n g d i r e c t l y to th e d i f f e r e n c e in h e i g h t g row th
of tu lip p o p la r.
A c om parison o f th e s o i l r e a c t i o n (pH) in b o th a r e a s does n o t
e x h i b i t any s i g n i f i c a n t v a r i a t i o n .
r e a c t i o n th a n A re a X.

A rea Y i s s l i g h t l y more a c i d in

B oth a r e a s a r e s t r o n g l y to v e ry s t r o n g l y a c i d end

th e B h o r i z o n a p p e a r s to be s l i g h t l y more a c i d th a n th e A o r 0 h o r i z o n s .
The lo w e s t i n d i v i d u a l pH v a lu e s a r e o b t a i n e d in th e B^ h o r iz o n of b o th
areas.

S o i l r e a c t i o n p e r s e does n o t a p p ea r to be d i r e c t l y c o n t r i b u t i n g

t o h e i g h t g ro w th d i f f e r e n c e s .

The pH v a l u e s , however, may be i n d i r e c t l y

a f f e c t i n g o t h e r s i t e f a c t o r s such as th e s o i l b i o l o g i c a l and h erb aceo u s
fa c to rs.
The p e r c e n t o f o r g a n ic m a t t e r i n e ach sam pling a r e a i s v e ry low.
G -re a test s t a t i s t i c a l d i f f e r e n c e s betw een a r e a s a r e found in th e Ag
h o riz o n .

The amount of o r g a n ic m a t t e r d e c r e a s e s w ith in c r e a s e d d e p th

f o r b o th A re a X and A rea Y.

S l i g h t l y g r e a t e r amounts of o r g a n ic m a tte r

a r e fo u n d in A rea Y a t th e A ^ A2 , and B2 h o r iz o n s ; th e amounts below th e
B2 h o r i z o n d i f f e r v e r y l i t t l e .

No s i g n i f i c a n t s t a t i s t i c a l d i f f e r e n c e

e x i s t s betw een A rea X and A rea Y i n s o f a r as th e d i r e c t e f f e c t of o rg a n ic
m a t t e r c o n t e n t i s c o n c e rn e d .

lUU

B o th c a rb o n and n i t r o g e n a r e fo un d in g r e a t e r amounts in A rea Y.
A ls o , t h e c a r b o n - n i t r o g e n r a t i o i s more narrow in t h i s a r e a , i n d i c a t i v e
o f g r e a t e r d e c o m p o s itio n o f c a rb o n ac eo u s and n i tr o g e n o u s m a t e r i a l .

The

d i f f e r e n c e i n t h e c a r b o n - n i t r o g e n r a t i o between a r e a s i s n o t e x tre m e.
R a t i o s f o r b o t h s i t e s f a l l w i t h i n th e ra n g e o f a p p ro x im a te ly 1 5 :1 to 23:1
f o r any one i n d i v i d u a l h o r i z o n .

The g r e a t e s t s t a t i s t i c a l d i f f e r e n c e f o r

t o t a l n i t r o g e n c o n t e n t i s fo u nd a t th e
and A re a Y.

h o r i z o n , when c o n t r a s t i n g A rea X

As w i t h t h e c o n te n t o f o r g a n ic m a t t e r , th e n i t r o g e n and

c a rb o n o c c u r in s l i g h t l y g r e a t e r amounts i n th e a r e a o f p o o r h e i g h t grow th.
D e c o m p o sitio n a p p e a rs t o b e more r a p i d in t h e more exposed and l e s s dense
site .
A c l o s e c o r r e l a t i o n e x i s t s betw een th e c a t io n-exchange c a p a c i t y and
t h e amount o f f i n e c l a y p r e s e n t i n A rea X.
marked in A re a Y.

T his r e l a t i o n s h i p i s l e s s

A c l o s e r r e l a t i o n seems to o ccur between t h e c a t i o n -

exchange and th e c o l l o i d a l com plex, th a n betw een c a tio n -e x c h a n g e and th e
o rg a n ic c o llo id s .

A n a ly s is o f v a r i a n c e r e v e a l s t h a t th e g r e a t e s t d i f f e r ­

ence betw een a r e a s f o r c a t io n -e x c h an g e c a p a c i t y e x i s t s a t th e A-^ h o r iz o n .
A rea Y has a l a r g e r t o t a l p r o f i l e exchange c a p a c i t y th a n A rea X.
The t o t a l b a s e c o n te n t shows no s i g n i f i c a n t d i f f e r e n c e between a r e a s .
A s l i g h t l y l a r g e r t o t a l b a s e c o n t e n t is found in A rea Y.

L argest in d i­

v i d u a l d i f f e r e n c e s a r e fo u n d a t t h e A2 h o r iz o n .
The p e r c e n t b a s e s a t u r a t i o n shows a l a r g e t o t a l p r o f i l e v a r i a t i o n
b e tw een A re a X and A rea Y.
a t th e C-], h o r i z o n .

T h is d i f f e r e n c e is s i g n i f i c a n t s t a t i s t i c a l l y

A c l o s e r c o r r e l a t i o n e x i s t s i n A rea X w ith r e f e r e n c e

to b a s e s a t u r a t i o n th a n in A rea Y.

1^5

The g r e a t e s t t o t a l exchangeable hydrogen is found in the area o f
poor h e ig h t grow th.

T his r e v e a ls th e c lo s e r e la t io n s h ip o f th e pH v a lu e s

o b ta in e d fo r th e same s o i l s , s in c e Area T e x h ib it s a s l i g h t l y g r e a te r
a c i d i t y than Area X, when a l l h o rizo n s are averaged.
Thus, a summation o f s i x r a th e r important s o i l chem ical p r o p e r tie s
by s o i l h o rizo n ten d s to show no o u tsta n d in g d ir e c t or s t a t i s t i c a l l y
s i g n i f i c a n t d if f e r e n c e betw een th e a rea o f good h e ig h t growth and poor
h e ig h t grow th o f t u l i p p o p la r.

The data b rin g out r a th e r v iv id ly th e

h o r iz o n a l d if f e r e n c e s , p o s s ib le environm ental fa c to r s r e s p o n sib le fo r
th e s e v a r ia t io n s , and th e magnitude o f the complex o f fa c to r s which
c o n tr ib u te to th e s e d if f e r e n c e s .
As a f u r t h e r v e r i f i c a t i o n o f th e ab se n c e of s t a t i s t i c a l s i g n i f i c a n c e
i n th e above s o i l p r o p e r t i e s , a p e r u s a l and summation o f i n d i v i d u a l
n u t r i e n t e le m e n ts v j i l l now be ta k e n u p .

An a tte m p t w i l l b e made to

r e l a t e t h e o v e r a l l m ajor chem ical p r o p e r t i e s to i n d i v i d u a l n u t r i e n t
s u p p l i e s o f th e same s o i l s .

T his combining and s u p p le m e n ta tio n o f a l l

chemical, p r o p e r t i e s p r e s e n t s an i n s i g h t i n to t h e t o t a l complex of
c h e m ic a l- e d a p h ic f a c t o r s in each a r e a .

lb G

Summary o f I n d i v i d u a l N u t r i e n t s

A t o t a l of s e v e n i n d i v i d u a l n u t r i e n t e lem en ts was i n v e s t i g a t e d and
r e c o r d e d by h o r iz o n and t o t a l p r o f i l e c o n te n t f o r b o th th e a r e a o f good
and p o o r h e i g h t g ro w th .
R e s u l t s o f t h i s i n v e s t i g a t i o n r e v e a l e d t h a t th e t o t a l amounts o f
a l l n u t r i e n t e le m e n ts d i d n o t d i f f e r a p p r e c i a b l y between A rea X and
A rea Y.

A p e r c e n t a g e summation, b a se d upon p e r c e n t o f t o t a l p r o f i l e ,

i s p r e s e n t e d in T a b le 1*3-

The t o t a l amount o f a l l n u t r i e n t s was v e ry

low f o r b o t h a r e a s :
TABLE ^3.
TOTAL INDIVIDUAL NUTRIENT ELEMENTS EXPRESSED AS A PERCENT
OF TOTAL PROFILE CONTENT FOR AREA X AND AREA Y
P ercent
A rea Y

A re a X
Ca - 3 U . 5 O

Ca - ^U.9 3

Mg - 2 ^ .6 5

Mg - 25.1*1

P - 1 U. 3 U

E - I O . 5O

K - 12.2S

P -

7-90

Na -

7-31

Fe -

5-75

Fe -

U .6S

Na -

3 .S3

Mn -

2 . 2b

Mn -

1 . 6S
1 0 0 .0 0 %

1 0 0 .0 0 fo

The r e s u l t s in T a b le *+3 g iv e th e o r d e r of m agnitude of n u t r i e n t
e le m e n ts in A rea X a s :

Ca> Mg>P > E > N a > F e >Mn.

A s l i g h t v a r i a t i o n in

147

t h i s o r d e r e x i s t s i n A rea Y a s i

Ca> Mg> K> P > Fe > Na> Mn.

The s t r i k i n g

s i m i l a r i t y i n b o th amount and m agn itud e o f n u t r i e n t e lem en ts i s r e v e a l e d
by c o n t r a s t i n g t h e a r e a o f good and p o o r h e i g h t growth*

A ltho ug h i t i s

n o t t o be assumed t h a t t h e t o t a l amount o f n u t r i e n t p r e s e n t d e te rm in e s
i t s a v a i l a b i l i t y to th e t r e e , t h e f a c t t h a t a t l e a s t one of t h e s e a r e a s
i s e x h i b i t i n g good h e i g h t grow th i s e v id e n c e t h a t th e t o t a l amount i s
s u f f i c i e n t to s a t i s f y th e t r e e re q u ire m e n ts u n d e r e x i s t i n g c o n d itio n s *
T hus, s i n c e th e two a r e a s a r e so s i m i l a r in actua,l c o n te n t of n u t r i e n t s ,
i t may be c o n j e c t u r e d t h a t b o th a r e a s have s u f f i c i e n t chem ica l n u t r i e n t s
to s a t i s f y t h e i r t r e e r e q u i r e m e n t s .

Hov/ever, in th e c a s e of A rea Y,

th e s e r e s u l t s d i s c l o s e t h a t some o t h e r f a c t o r may b e masking t h e n u t r i e n t
s u p p ly a s 8, cau se f o r p o o r h e i g h t grov/th.
The s t a t i s t i c a l summary (T a b le 42) o f a l l c h em ical n u t r i e n t s u n der
i n v e s t i g a t i o n r e v e a l s t h a t s i g n i f i c a n t d i f f e r e n c e s o c c u r f o r phosphorus
a t t h e Br, h o r i z o n , p o ta s s iu m a t th e A^ and
th e A^ h o r i z o n .

h o r i z o n s , and sodium a t

I f th e n u t r i e n t c o n te n t had been d e term in e d by t h e u s u a l

methods o f many i n v e s t i g a t o r s , o n ly th e upperm ost h o riz o n s would have
shown any d i f f e r e n t i a t i o n .

However, by e x t r a c t i n g s o i l samples a t th e

n a t u r a l h o r i z o n f o r each p r o f i l e , a c l e a r e r d i a g n o s i s as to h o riz o n
d i f f e r e n t i a t i o n , l e a c h i n g e f f e c t s , p r e s e n c e o f f i n e c l a y , and o rg a n ic
m a t t e r can be f u l f i l l e d .

The i m p l i c a t i o n o f t h e s e d i f f e r e n c e s f o r

p h o s p h o r u s , p o ta s s iu m , and sodium i s n o t to be i n t e r p r e t e d d i r e c t l y in
term s o f l i m i t i n g f a c t o r s .

R a t h e r , th e s t a t i s t i c a l d i f f e r e n c e s a r e

i n d i c a t i o n s of s u p p le m e n ta l f a c t o r s which l i m i t a p a r t i c u l a r n u t r i e n t
e le m e n t in any one h o r i z o n .

I f th e d i f f e r e n c e s had been extrem e i n t h e i r

m a g n itu d e , i t would be j u s t i f i a b l e to s u s p e c t a p o s s i b l e l i m i t i n g f a c t o r

148

table

44.

A COMPOSITE SIMULATION OF CHMCAL-EDAPHIC CHARACTERISTICS
BY SOIL HORIZON FOR AREA OF GOOD HEIGHT GROWTH AND AREA
OF POOR HEIGHT GROWTH OF TULIP POPLAR

02

+»
•H i
O

a00

ta

a} to*

S3
O
N

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43
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CD
43
43
ca
s
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S3
CD
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Ft
43
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^5

S
Fh
o

+3
O
Eh

o

o ^
<D £tD
t*D O
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a

ft

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o
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4-»
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o

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02

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■cc R

CD
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a

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CD
S3

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ft
ft

p

<0
atiD

at

o
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a

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<0

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CD
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<D
ca

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ft

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CO

CO

ca
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ft

■ri

-d
O

CO

A rea X

LAi
a2
b2
b3
°1
IIA-i

4

b2

C1

5*55
5-33
5.4o
5.42
5.1S

2.35
.96
.71
•35
. 28

.125 S .20
.0U7 6.08
.049 10.64
—,
3.32
—
1.44

5.39
5.20
5.15
5.1U
5.40

1.72
.71
.66
.4-0
.28

.113
,0W
.okl
——
—

6 .so
e.ko
8.40
4 .os
1.60

.63 7.69 7.57
.46 7.64 5.61
*5? 4.91 10.12
.34 10.20 2.9S
.22 15. U3 1.22

.3U
.19
.20
.06
.02

, 12
.10
.11
.09
.OS

.02
.07
.09
.04
.03

.06
.03
.OS
.07
.04

.03
.02
.01
.06
.02

.02
.02
.04
.01
.02

.03
.02
.00
.00
.00

.52
• 5U
.72
.3s
.32

6.28
5.S6
7.6S
3.70
1.2S

.19
.22
.29
.06
.04

.13
.13
.13
.12
. 12

.05
.10
.11
.09
.05

.06
.03
.10
.06
.04

.04
.03
,0b
.02
.o4

.01
.03
.02
.02
.00

.03
.00
.00
.00
.00

7.69
S.U7
s . 56
9.37
20.00
A rea I

:i i a -,
4

b2
b7

Cl
IVA-,

£BP
c.
C3!

5.35
5.16
5.02
5.17
5-42

2.6 6
1.18
.S3
•35
.35

.133 7.72
.072 10.6s
.060 11.88
—— 1.76
—
.00

. s i IO.53 6.91
.71 6.61 9.97
.S3 6.97 11.05
.23 17.17 1.13
.00
.00
. 24

.53
.4 i
.47
.03
.o4

.14
. 12
.14
.09
.09

.03
.05
.04
.03
.05

.03
.06
.11
.05
.03

.02
.01
.02
.02
.01

.01
.05
.05
.01
.00

.04
.00
.00
.00
.00

5-35
4.94
4.70
4.83
5. S2

1.65
.90
.75
.31
.14

.121 10.96
.05U S .72
.055 S .23
6 .Us
—
s .s u

.45
.60
.50
.31
.23

4.06 10.51
6.92 3.12
6.09 7.77
4.85 6 .I6
2.56 s . 61

.19
.32
.17
.04
.02

.14
.13
.13
.12

.05
.05
.04
.04
.02

•°?
.04
.07
.05
.03

.01
.02
.04
.02
.02

.02
.04
.05
.02
.01

.01
.00
.00
.01
.00

1^9

f o r a c e r t a , i n n u t r i e n t e le m e n t.

Thus, a h o r iz o n d i f f e r e n t i a t i o n f o r

n u t r i e n t s u p p ly i s im p lie d hy t h e s e r e s u l t s .

Any one elem ent c o n s id e re d

p e r s e i s o b v io u s ly n o t th e one " b e s t 11 c o n d i t i o n f o r a d i f f e r e n c e in
h e i g h t g ro w th .

The r e s u l t s o b t a i n e d h e r e a r e in agreem ent v ;ith a s i m i l a r

s tu d y by A uten (19^5)*

Auten fo u n d g r e a t d i f f e r e n c e s in th e q u a n t i t y o f

r e p l a c e a b l e n u t r i e n t s f o r s o i l s on 77 d i f f e r e n t y e llo w p o p l a r s t a n d s .
The d i f f e r e n c e s he fo u n d in c a lc iu m c o n te n t o f th e

h o r iz o n were n o t

g r e a t enough t o j u s t i f y u s in g c a lc iu m a s a c r i t e r i o n of s i t e index*

No

r e l a t i o n c o u ld be d e m o n s tra te d betw een magnesium, p h o sp h o ru s, o r p o ta s s iu m
c o n t e n t of s o i l and s i t e in d e x .

The r e s u l t s o f th e p r e s e n t i n v e s t i g a t i o n

on t u l i p p o p l a r , a s w ith s e v e r a l o t h e r s t u d i e s of t h i s ty p e , c o n clu d e
t h a t m in e r a l n u t r i e n t s a r e e s s e n t i a l to grow th o f t u l i p p o p l a r , b u t in
th e s o i l s examined th e y do n o t o c c u r in l i m i t i n g amounts.

The u t i l i ­

z a t i o n o f n u t r i e n t s by t u l i p p o p l a r depends n o t a lo n e on th e p r e s e n c e o f
a p a r t i c u l a r amount of an elem ent i n th e s o i l , as i t does upon t h e i n t e ­
g r a t i o n of o t h e r grow th f a c t o r s .

From t h e s e r e s u l t s i t i s a p p a r e n t t h a t

u n f a v o r a b l e c o n c e n t r a t i o n s o f i n d i v i d u a l chem ica l elem en ts do n o t e x i s t
a s a l i m i t i n g f a c t o r , u n l e s s masked by th e p r e s e n c e o f some f a c t o r n o t
in v e stig a te d .
I n a p p r a i s i n g th e v a lu e o f t h e p r e s e n t c h em ical i n v e s t i g a t i o n s ,
v a r i o u s l i m i t a t i o n s a r e imposed upon th e i n t e r p r e t a t i o n o f th e r e s u l t s .
For t h i s s t u d y , i t i s s u f f i c i e n t to i n t e r p r e t th e r e s u l t s in c o m parative
term s betw een two o pp osing s i t e s f o r t u l i p p o p la r and to r e l a t e th e s e
d i f f e r e n c e s to o t h e r s i t e and h a b i t a t f a c t o r s .

For a com plete i n t e r p r e ­

t a t i o n o f r e s u l t s o b t a i n e d h e r e , more knowledge c o n ce rn in g th e s o i l
f e r t i l i t y l e v e l o f t u l i p p o p l a r and i t s c o r r e s p o n d in g s i t e q u a l i t y would

150

have to h e known.

No su ch d e t a i l e d c h em ical knowledge has "been r e f i n e d

in re c e n t i n v e s t i g a t i o n s .
I n c o n c l u s i o n , th e i n v e s t i g a t i o n of f o u r t e e n i n d i v i d u a l s o i l chem ical
p r o p e r t i e s in th e a r e a o f good and p o or h e ig h t grow th of t u l i p p o p l a r ,
r e v e a l no o u t s t a n d i n g d i r e c t o r s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s
which a r e i n d i v i d u a l l y c o n t r i b u t i n g to a h e ig h t grow th d i f f e r e n t i a l .
The manner in which th e n u t r i e n t e lem en ts a r e r e l a t e d to th e
p h y s i c a l , c l i m a t i c , and b i o l o g i c a l p r o p e r t i e s of t h e same s o i l ty p e s
w i l l be p r e s e n t e d in t h e i n t e g r a t e d summary of a l l f a c t o r s a f f e c t i n g
t h e h e i g h t g ro w th o f t u l i p p o p l a r .

151

FIELD-PLANTATIOH EXPERIMENTS
G-rowth Hate o f T ulip P oplar
Stem A n a ly sis
In order to o b ta in some e stim a te o f th e growth o f t u lip p o p la r ,
s e v e r a l t r e e s r e p r e s e n ta tiv e o f b o th good and poor h e ig h t grow th, were
f e l l e d and s e c t io n e d .

By t h is method, th e in v e s t ig a t o r was a b le to

determ ine to what e x te n t the e x te r n a l fa c to r s o f s i t e were c o n tr ib u tin g
to the growth o f in d iv id u a l t r e e s , as ex p ressed by h e ig h t and r a d ia l
grow th.

A com plete stem a n a ly s is o f each tr e e was undertaken by record in g

th e h e ig h t and d iam eter growth a t th e stump and a t o n e -fo o t s e c tio n s
a lon g th e stem .

Prom th e s e d a ta , cu rves o f h e ig h t a g a in st d ia m eter, h e ig h t

a g a in s t age in y e a r s , diam eter a g a in s t a g e, and growth r a te s were o b ta in ed .
These cu rves r e p r e se n t a grap h ic e x p r e ssio n o f growth by r e la t in g d i f f e r ­
en ces in h e ig h t and diam eter fo r two d if f e r e n t s i t e s , Area X and Area T.
R ad ial grow th was measured f o r each o n e -fo o t s e c t io n up th e stem by
r ec o r d in g th e w idth o f annual r in g along a maximum and minimum r a d iu s,
u sin g an o c u la r m icrom eter and m icro sco p e.

By t h is method i t was p o s s ib le

to determ ine corresp ondin g r a te s o f h e ig h t and diam eter growth f o r each
area a t a p a r t ic u la r y e a r , and th us r e c o n str u c t the mean annual growth
o f th e tr e e*

By com bining th e s e d ata w ith the growing season p r e c ip it a t io n ,

i t i s p o s s ib le to a s c e r t a in w ith in l i m i t s , th e e f f e c t o f p r e c ip it a t io n upon
h e ig h t and d iam eter grow th.

I t was not n e c essa ry to o b ta in a measure o f

the volume growth o f th e tr e e s in c e th e p r e se n t stud y is p r im a r ily con­
cerned w ith the e f f e c t o f s i t e upon tr e e grow th.

For a s in g le s p e c ie s ,

such as t u l i p p o p la r , v a r ia t io n in h e ig h t growth due to v a r ia tio n s in the

152

s ite fa c to rs

a r e f o u n d to be c l o s e l y c o r r e l a t e d w ith v a r i a t i o n s in h e i g h t

and d i a m e t e r g ro v /th .

Thus, h e i g h t grov/th becomes a u s e f u l t o o l a s an

in d e x o f s i t e .
The c u rv e s which f o l l o w g iv e g r a p h ic e x p r e s s i o n o f th e d i f f e r e n c e
i n s i t e due to c l i m a t i c and e d a p h ic f a c t o r s .
same age and d e n s i t y ,

S in c e a l l t r e e s a r e o f th e

t h e s e two v a r i a b l e s a r e c o n s t a n t f o r b o t h s i t e s .

T h is f a c t le n d s added v a l i d i t y t o th e r a t h e r d i r e c t c o r r e l a t i o n o f h e i g h t
and d ia m e te r grovrth to th e e f f e c t s o f th e grow ing s e a s o n p r e c i p i t a t i o n .
S e a so n a l Course o f H e ig h t G-rowth
S e v e r a l t e r m i n a l b ra n c h e s o f t r e e s in A rea X and A rea Y were marked
w ith a c ra y o n i n A p r i l 1952, p r i o r to t h e b re a lrin g o f dormancy.

At

s u c c e s s i v e i n t e r v a l s th ro u g h o u t th e grow ing s e a s o n , th e r a t e o f gro w th
was m easu red in o r d e r to d e te rm in e th e e f f e c t i v e seaso n ed r a t e of grov/th*
The r e s u l t s of t h e s e measurem ents showed t h a t th e e f f e c t i v e h e i g h t grow th
f o r t h i s s p e c i e s o c c u r r e d betw een th e d a t e s A p r i l I S , 1952 to August 1,
1952.

P r a c t i c a l l y no h e i g h t g ro w th o c c u r r e d in e i t h e r a r e a a f t e r

A ugust 1 , 1952.

T h is in f o r m a t io n r e v e a l e d t h a t c l i m a t i c and ed ap h ic

f a c t o r s o p e r a t e most e f f e c t i v e l y on h e i g h t grow th betw een t h e above d a te s
f o r th e 1952 grow ing s e a s o n .

A p e r i o d o f 105 days was th e e f f e c t i v e

g row th p e r i o d f o r t h i s s p e c i e s u n d e r th e c l i m a t i c c o n d i t i o n s of th e e x p e r i ­
m e n ta l a r e a .

S in c e r e p l i c a t i o n o f th e s e a s o n a l c o u rs e o f h e i g h t grow th f o r

s e v e r a l y e a r s i s n e e d e d , i t i s im p o s s ib le to a p p ly t h e above d a t a to
p r e v i o u s o r l a t e r s e a s o n a l grovrth y e a r s .

More d a t a a r e n e e d e d , p e rh a p s

t h r e e to f i v e grow ing s e a so n a v e r a g e s , b e f o r e any a p p ro x im a te a v e ra g e
g row ing s e a s o n p e r i o d can be d e te rm in e d f o r t h i s a r e a .

153
TABLE U5 .

COMPLETE STEM ANALYSIS POE TULIP PQPLAE ON A GOOD SITE

Area X (Good h e ig h t grov/th)
Cross s e c t i o n number
and h e ig h t in f e e t
from ground l e v e l

d .o .h .
d .i.h .
(T enth in ch es)

1

6.02

2
3
4
5
6

5.72
5JO
5 . 4o

7

5*07

8

5.27

5.20

5.00

12

4.87
4.77
4.70
4.70

13

4.50

9
10
11
14

15

4.4o
4.4o

16

4.17

17
IS
19

4.00
4.03

21
22

3.60

2?
24
25
26
27
2S
29
30

3.50

20

31

32
33

3-90
3*90
3.50

3*50
3.20

2.97
2.95
2.70
2.60
2.47
2.25
2.20
2.27

34

1 .8 5

35
36
37
38
39

1.65

40

1.55
1.32
1.10
1.00

.90

4l
42

.52
.50

43

.3 0

44
T o ta l H e ig h t 4 4 ’ 1 "

.29

5.62

5J2
5*29
4.93
4.S6
4.so
4.73
4.70
4.6o
4.50

4.4o
4.4o
4.20
4.10
4.17
3.93
3J5
3 . SO
3.65
3.60
3 . 4o
3.30

3-32
3*35
3.00

2.80
2.80
2.55
2.45
2.30
2 .1 0

2.03
2 .1 2

1.73
1.55
1 . 4o
1 .2 0

1.00

.90
.80
.49
.47
.27
.26

Number o f
E ings

Bark
T hickness

15
i4
14
13
13

.40
.40
.41
.47
.41
.40

12
12
12
12

11
11
11
11
10
10
10
10

9
9
9
8
8
8
8

7
7

7
7

6
6
6
6

5
5
5
4
4
4
3
3
3
2
2
2

.34
.30
.27
.27

.30
.30
.30
.30

•2?
.24
*25
.23
.25
.30
.20
.20

.18
*15

.20

.17
.15
.15
.15
.16

.15
.17
.15

.1 2
.10

.15
.12

.10
.10
.10

.03
.03
*03
.0 3

15H

TABLE H 6.
COMPLETE S T M ANALYSIS TOR TULIP POPLAR ON A POOR SITE

A rea Y (P o or h e i g h t grow th)
Gross s e c t i o n number
and h e i g h t i n f e e t
from g ro u n d l e v e l

d .o .b .
d .i.b ,
(T e n th in c h e s)

5.63
M5

Ground l e v e l

1
2

If-.IO

}4

3.60
3-25
3.00
2.93
2.70
2.67
2.30
2.25
1.80
1.57

5
6
7

g
9

10
11
12
13

l.H S

1.39
1.10
.93
.60

Ik

15
16

17
18
19
20

.*3
.20

Number o f
Rings

U.90
3 . SO
3.65
3.25
3.00
2.60
2.65
2.52
2.H0
2.10
2.00
1.62

l.Uo

1.35
1.23
1.00

.S3
.55
.HO

.38
.16

14
13
12
11
11
11
10
10

9
9
s
8
7
6

6

5

k
k
3
2

Bark
T h ic k n e ss

•73

•55

.H5
-35
.25

-Ho
.28
.18
.27
.20
.25
.18
.17
.13
.16
.10
.08

.05
.05
.05

.oH

T o t a l H e ig h t 2 0 1 5"

I n t e r p r e t a t i o n of R e su lts
A lth o u g h th e c u r v e s and g r a p h i c m a t e r i a l which f o ll o w a r e in some
r e s p e c t s s e l f - e x p l a n a t o r y , f u r t h e r e l u c i d a t i o n of t h e s e r e s u l t s w i l l be
g iv e n i n term s o f s i t e q u a l i t y i n t e r p r e t a t i o n .
F i g u r e 22:

The c u rv e o f h e i g h t a g a i n s t d ia m e te r b r e a s t h ig h ( d . b . h . )

e x p r e s s e s t h e r e l a t i o n betw een h e i g h t and d ia m e te r f o r two s i t e s , A rea X
and A re a Y.

The a r e a o f good h e i g h t grow th (A rea X) f o ll o w s t h e general.

155
Fig*

45

22.

CURVES SHOWING RELATIONSHIP BETWEEN
HEIGHT AND DIAMETER GROWTH OF T U II P POPLAR
IN AREA X AND AREA Y

40

35

30

AREA X

H eig h t
in
Feet

20

15

10

AREA Y
5

*5

1 .0

1 .5

2 .0

2 .5
3 .0
3 ,5
DBH i n INCHES

4 .0

4 .5

5 .0

5 .5

5 .0

Pig. 23.

45

TYPICAL OUPYEC S H C W m nKE R3LATION3H IP
BETWEEN HEICHT CPCYTH 0 ? TU L IP POPLAR FOR AREA
OF 3 0 0 D HEITHT CRCWTK v s . AREA OF POOR HSIC-HT 1RCWTH

40

35

30

AREA X

l^ h t
in
'e e t
25

20

15
AREA Y

10

5

1

2

3

4

6

5
A ^e

7

( Y e a r s )\

8

9

10

11

12

13
1 0 51

157

sig m o id ty p e o f g ro w th , w h e re a s , A rea Y d e p a r t s from t h i s ty p e c u rv e .
T h is d i f f e r e n c e in form o f c u rv e f o r th e two s i t e s in v o lv e d i s a r a t h e r
d i r e c t e x p r e s s i o n o f e d a p h ic and c l i m a t i c f a c t o r s c o n t r o l l i n g th e grov/th
of in d iv id u a l tr e e s .

The c u rv e f o r A rea X e x h i b i t s a r a t h e r r a p i d

i n i t i a l g ro w th in r e g a r d to h e i g h t a t th e expense of d ia m e te r grov/th;
t h i s a c c e l e r a t i o n i n h e i g h t i s i n c r e a s e d d u r in g th e g ran d p e r i o d o f
g ro w th and th e n t a p e r s o f f s l i g h t l y , b u t s t i l l grow ing a t a r a p i d r a t e
in h e i g h t .

A re a Y e x h i b i t s a v e r y slow i n i t i a l h e i g h t grov/th and th e

c u rv e d e p a r t s from t h e sig m o id fo rm .
F i g u r e 23!

The c u rv e s o f h e i g h t g ro w th a g a i n s t age i n d i c a t e th e

r a t e o f h e i g h t g ro w th th ro u g h o u t a 13 - y e a r p e r i o d , as v;ell as h e i g h t in
any one p a r t i c u l a r y e a r .

The t r e e s i n A re a X show a marked c o n c a v ity in

t h e i r i n i t i a l h e i g h t grov/th and th e n t a p e r o f f g r a d u a l l y to w ard s th e
convex ty p e o f g ro w th in th e g ra n d p e r i o d o f grov/th.

A rea Y e x h i b i t s

l e s s c o n c a v ity i n th e i n i t i a l p e r i o d o f h e i g h t grow th and th e n shows
marked c o n v e x it y a t an e a r l y s t a g e o f h e i g h t grov/th.

T h is i n d i c a t e s t h a t

th e t r e e s i n A re a Y a r e growing a t a s lo w e r r a t e o f h e i g h t grov/th th a n
t r e e s i n A rea X.

The c u rv e s d i s c l o s e t h a t A re a Y is 11im m ature 11 i n i t s

i n h e r e n t grov/th p a t t e r n and t r e e s in t h i s a r e a a r e n o t r e a c h in g th e
d e s i r e d h e i g h t i n h e r e n t in t h e g ro w th p a t t e r n f o r t u l i p p o p l a r .
F i g u r e 2*+:

The g r a p h ic e x p r e s s i o n o f th e r a t e o f a n n u a l h e i g h t

g ro w th f o r b o t h s i t e s i s g iv e n in t h i s c h a r t .

The p a t t e r n o f grov/th

f u r t h e r e l a b o r a t e s upon th e f i n d i n g s shown i n F ig u r e 2 3 .

Thus, a

r e c o n s t r u c t i o n o f t h e h e i g h t g ro w th r a t e f o r any one y e a r o r p e r i o d o f
y e a r s i s p r e s e n t e d in t h i s g r a p h .

Pig. 24
AREA X
1951

15S

A COMPLETE STEM ANALYSIS OF TULIP
POPLAR SHOEING- CORRESPONDING RATE OF
ANNUAL HEIGHT GROWTH IN AREA X v s . AREA Y
(1 9 3 8 -19 51)

1950

1949

1948

1947

1946

1945

AREA Y
20

1944

1943

1047

15
H e ig h t
in
Feet

1942

10

1941

5
1940
103°

1940

1°38
R a t e o f H e i g h t G rovrth

159

F i g u r e 251

The d i f f e r e n c e i n th e a n n u a l r a t e and e x t e n t o f r a d i a l

g ro w th by y e a r s i s p r e s e n t e d in t h i s f i g u r e *

A g ain , A rea X e x h i b i t s th e

u s u a l sig m o id ty p e of r a d i a l g ro w th ; A re a Y f o ll o w s th e p a t t e r n o f "open
grov /th 11 t r e e d i a m e t e r , w i t h a c o n s t a n t i n c r e a s e in r a d i a l t h i c k n e s s a t
t h e ex p en se o f h e i g h t grovrth.
o f t h e c u rv e f o r A rea Y.

I t i s s i g n i f i c a n t to n o te th e c o n c a v ity

T h is r a t h e r " u n n a t u r a l 11 i n h e r e n t te n d e n c y f o r

grov7th o f t u l i p p o p l a r c o n n o te s a d i r e c t e x p r e s s io n o f u n f a v o r a b le s i t e
q u a l i t y , v/hen c o n t r a s t e d to A rea X.

I t a l s o s i g n i f i e s t h a t d ia m e te r

grov/th i s n o t i n p r o p o r t i o n to h e i g h t grov/th f o r A rea Y, an a d d i t i o n a l
ex p re ssio n o f s i t e q u a lity .
F ig u re 2 6 :
F i g u r e 2^ .

This g ra p h i s a n alo g o u s to t h o s e o f h e i g h t grovrth in

D ia m eter grov/th f o r c o n t r a s t e d A rea X and A rea Y e x h i b i t s

g r e a t e s t d iv e r g e n c e d u r in g t h e somewhat c r i t i c a l s t a g e s o f s e e d l i n g
developm ent ( 19^6 to 19 ^ 8 ) .
F ig u re 27i

The c u rv e showing th e e f f e c t o f s i t e q u a l i t y upon b a rk

t h i c k n e s s f o r b o t h a r e a s i s f u r t h e r e v id e n c e o f th e e f f e c t o f e x t e r n a l
f a c t o r s c o n t r o l l i n g th e grow th form o f t h e tr e e *

I n Area Y, t h e b a rk

t h i c k n e s s i s g r e a t e r a t th e low er p o r t i o n o f t h e b o l e th a n in A rea X.
S in c e th e t r e e s o f b o t h a r e a s a r e o f t h e same age and d e n s i t y , th e b a r k
t h i c k n e s s r e v e a l s a r e s p o n s e to e n v iro n m e n ta l f a c t o r s o f th e s i t e .

The

b a r k o f t u l i p p o p l a r i s t h i n , and th u s i t s t h i c k n e s s e x h i b i t s a d i r e c t
re s p o n s e to i n t e r n a l f a c t o r s .

The marked i n c r e a s e in b a rk t h i c k n e s s in

th e i n i t i a l s t a g e s o f grow th in A rea Y as compared to A rea X, i s e v id en c e
o f t h e d e v i a t i o n from n o rm a l, i n h e r e n t grov/th of t u l i p p o p l a r .
G e n e r a l l y , f o r e s t t r e e s w hich a t t a i n t h e i r maximum developm ent on
s i t e s h a y in g an abundance o f a v a i l a b l e s o i l m o is tu r e p o s s e s s t h i n n e r b a rk

F ig . 2 5 .
160

TYPICAL CURVES 3HCV/IK3- THE ANNUA1 RADIAL- CRCV7TH
OF TU LIP PC PI. AP. FOR A” EA X AND AREA Y

5 .5

5 .0

4 .5

AREA X

4 .0
D .0 ,B .
in
Inches
3 .5

AREA Y

3 .0

1 .5

1. 0

2
1933

3

5

6

7

8

Age ( Y e a r s )

Q

10

11

12

13

14
1951

F ig .

26.
161

A COMPLETE 3TEM ANALYSIS OF TULIP POPLAR
SHOWING CORRESPONDING RATE OF ANNUAL RADIAL
GROV/TH IN AREA X v s . AREA Y
(1 9 4 1 -1 9 5 1 )
AREA Y
1941

AREA X

1942
1941
1943

1 .5

1944

2.0
1942
2 .5
1946

1948

3 .5
D .O .B .
In
In ch es

1944
1949

4 .0
1945

1950

1946
5 .0

1947

«5

1951
1949
1950

6 *°

1951

Rat© o f D i a m e t e r G r o w th

Fig.

27.

THE EFFECT OF S ITE QUALITY UPON BARK
THICKNESS OF TUI.I P POPLAR IN AREA X v s . AREA v
45

40

35

AREA X
30
H e ig h t
In
Feet
25

20

/ \

15

10

5

♦ 7 .6 . 5 *4 . 3 .2 .1
0
B a rk T h ic k n e s s I n T e n th I n c h e s

162

163

than t r e e s on s i t e s o f low a v a ila b le m o istu re .

Thus, a s tr u c tu r a l

v a r ia t io n a t the b a se o f th e t r e e s in Area Y, as e x h ib ite d by g r e a te r
developm ent o f v a s c u la r and sclerenchym a t i s s u e , i s a v a r ia tio n which
adapts i t s e l f to r e g u la tio n o f w ater l o s s through tr a n s p ir a tio n .

This

a d a p ta tio n i s in d ic a t iv e o f th e p h y s io lo g ic a l "dryness" o f the s i t e
in Area Y.

The form a tio n o f g r e a te r amounts o f cork and bark t is s u e

on th e t r e e s o f th e d r ie r s i t e se r v e s as an e f f e c t i v e check on th e l o s s
o f w ater from th e main a x is and branches o f th e s e t r e e s .

In Area X,

th e t r a n s p ir a tio n appears to be optimum fo r the s i t e as evid en ced by
th e normal ta p er o f the bark and stem .

Thus, th e e x te r n a l f a c t o r o f

bark th ic k n e s s as r e la t e d to tr a n s p ir a tio n and w a .te r -lo ss , i s in d ic a ­
t i v e o f th e b e t t e r s o il- m o is t u r e r e la t io n s h ip in Area X.

The E f f e c t o f Growing Season P r e c i p i t a t i o n and Tem perature on
H e ig h t and D ia m e te r Growth o f T u l ip P o p l a r f o r a 11-Y ear P e r i o d

P r e c i p i t a t ion
H aving s t u d i e d t h e g e n e r a l e f f e c t s o f c l i m a t e and o t h e r s i t e f a .c to r s
upon t h e g ro w th form o f t u l i p p o p l a r by means o f a co m plete stem a n a l y s i s ,
an i n v e s t i g a t i o n was c o n d u cte d to a s c e r t a i n th e p o s s i b l e e f f e c t s o f
grow ing s e a s o n p r e c i p i t a t i o n and te m p e r a tu r e on h e i g h t and ra d ia l, g ro w th .
P r e c i p i t a t i o n and te m p e r a tu r e d a t a were o b t a i n e d f o r th e grow ing sea so n
f o r t h e y e a r s 1939-1951*

S in c e t h e y e a r s 193^* 1939i and 19*+0 were

c r i t i c a l f o r e s t a b l i s h m e n t of th e young s e e d l i n g s , t h e s e y e a r s were
o m itte d from th e d a t a and o n ly th e p e r i o d 19 ^ 1 -1 9 5 1 was c o n s id e r e d in
r e l a t i o n to growth*

The e f f e c t o f th e p r e v i o u s y e a r ’ s p r e c i p i t a t i o n upon

h e i g h t g ro w th was n o t i n v e s t i g a t e d .
The grow ing s e a s o n f o r Cass County, M ich ig an , i s c o n s id e r e d to be
from May 6 to O c to b e r 15 i n c l u s i v e (1 6 2 d a y s ) .

The p e r i o d betw een t h e s e

d a t e s was th u s in c lu d e d in r e l a t i n g p r e c i p i t a t i o n and te m p e r a tu r e to
h e i g h t an d r a d i a l g ro w th o f t u l i p p o p l a r .

A t a b u l a t i o n o f th e growing

s e a s o n p r e c i p i t a t i o n and te m p e r a tu r e f o r th e y e a r s 1939-1951 was o b ta in e d
from t h e U. S. D epartm ent o f Commerce and is p r e s e n t e d in T a b le h7*

From

t h e s e d a t a i t i s p o s s i b l e to o b s e rv e th e f l u c t u a t i o n in grow ing s e a s o n
p r e c i p i t a t i o n and te m p e r a t u r e f o r th e e x p e r im e n ta l a r e a f o r th e p e r i o d
1 9 ^1 -1 9 5 1 .

I n th e v i c i n i t y o f Dowagiac, M ichigan, t h e g r e a t e s t p r e c i p i ­

t a t i o n o c c u r s d u r in g May and J u n e , w h ile th e " d ry 11 p e r i o d is u s u a l l y in
J u l y and A u g u st.

T h is s e a s o n a l d i s t r i b u t i o n of r a i n f a l l i s r a t h e r d e f i ­

n i t e l y a s s o c i a t e d w ith t h e grow th and s u r v i v a l o f t u l i p p o p l a r p l a n t a t i o n s

TABLE U7 .

165

A TABULATION OF THE GROWING SEASON PRECIPITATION FOR TULIP POPLAR (1939-51)
S t a t i o n - Dowagiac, M ichigan *
May

June

Ju ly

August

Y ear

19^
Ui
U2

l.lU
\
M 3

6 .0 S
5 .7 S
3*87

2.89
3.US 2.U3
*+3 12.3s 5.2s
UU U.iU
S' _ _
6.00
U6 3 . 7 6 3 . 7 7
6.27 6.33
U7
Us 6.55 3.86
1+9 6.5U 6 - 3 7
50 1.8U 9 .uU
U.13 2 . 7 3
1951

Mean

63.65 63.9s
U.S9 U.92

September

R a i n f a l l in in c h e s
.7 8
7.^3
.7 6
6 . 7k
.7 8
2.63
2.86
1*97
6.23
3.90
2.75

U.oU

U.5U

3.60

2.91

1 . 3^
3^3

1.87

2.27
5.39

O c to b er

T o tal

6 months
2.79
2.59

12.76
2.35
1.76

2.60
2.17
3.U6
•7U
1.03

22.26
21.1S
26.98

21. lU
3 0 . U7
15.77
23.70
18.20

3.56

2.22
l.6s
2.19
2.22
2.70
.lU
U.20

L.26
6.35

U.22

21.81
25.19

38.59

^3*27

U2.SU

U0.U9

292.82

2.97

3*33

3.29

3 .1 1

22.53

.63
2.62
2.32
3.U0
5.U2

U.90
3.95
2.89
2.75

3*31
.71

T o tal
Annual

22.10

18.87

25.15

3 7 .2U
35.95

U0.05
37.71

U6.27
28.72

36.38
30.29
39.58

3U.3O
36.6S
U3.27
U2.02

A verage o f 37 y e a r s ~ 3^*77 in c h e s o f a n n u al p r e c i p i t a t i o n .
Growing s e a s o n f o r Cass County, M ichigan = 162 days (May 6 - O cto b er 1 5 )

A TABULATION OF THE GROWING SEASON TEMPERATURE FOR TULIP POPLAR (1939-51)
S t a t i o n - Dowagiac, M ichigan *
May

June

Ju ly

Year
1939

September

O cto b er

D egrees F a h r e n h e i t
—

71.7
6 S. 2

uo 5U.8
Ul 61.6 69.2
U2 5 9 . 2 6 S . U
^3 5U.5 71.3
UU 61.S 69.7
U5 5 3 . 0 6L.7
U6 5U.1 68.0
U7 5 3 -U 6U.0
Us 5U.6 65.U
U9 63.6 71.6
50 62.1 68.0
6 8 .8

1951

61.9

T o tal

639.8 7U9.1
58.1 6 8 .1

Mean

August

71.9

72.S

72.5

71.8
73*0

71.6
72.0
7U.7
70.S
73.5
7 6 .3

71.u
72.0
71.0
6s.U
72.2
71.8
71.8
67.6
8 1 .8
7 U. 1
71.5

67.6
61.6
65.8
60.9
59.7

65.2

66.1

6U.U
6U.U
67.3

5U.U
5U.2
5 5 .u
51.6
50.0
U9 . 5
51.8
56.6
61.7
Us.7
56.1

Mean
6 months

67.u
63.9

65.9
63.U
63.5
6U.9
63.2
6U.2
66.0
63.9
6 6 .2
65.0
6U.U

70.2

69.2

72.9

67.7

58.6
6U.0
60.6

799*3

787.1

697.0

592.5

710.6

72.6

71.5

830

5 3 .8

6U.6

56.5

5U.6

* U.S. D epartm ent o f Commerce, W eather B ureau
E a s t L a n s in g , M ichigan

Mean
Annual
—

^ 7 .3

50.7

HS.6
^7 . 5
^9 - 3

U9.6
---------

US.8
—

US.9
us.7

166

i n t h e v i c i n i t y o f s o u t h e r n M ich ig an ,

The manner in which p r e c i p i t a t i o n

a f f e c t s th e h e i g h t and r a d i a l gro w th o f t h i s p l a n t a t i o n w i l l now he
c o n sid e re d .
By u s e o f t h e c o r r e l a t i o n c o e f f i c i e n t ,

i n c o n ju n c t io n w ith

g r a p h i c a l i n t e r p r e t a t i o n , i t was p o s s i b l e to d e m o n s tra te th e e f f e c t o f
g row ing s e a s o n p r e c i p i t a t i o n on th e h e i g h t and r a d i a l grov/th o f t u l i p
p o p la r.

T h is ty p e o f c o r r e l a t i o n i s u sed to m easure t h e dependency o f

one o b s e r v a t i o n on a n o t h e r ; th e v a lu e o f r can n o t exceed 1 . 0 , and a u n i t
i n c r e a s e o r d e c r e a s e i n one o b s e r v a t i o n w i l l c a u s e a c o rre s p o n d in g change
in th e o th e r o b serv atio n .
From t h e c o m p le te stem a n a l y s i s , v a l u e s f o r t h e a c c u m u la tiv e r a d i a l
and h e i g h t gro w th were o b t a i n e d f o r A rea X and A rea Y (T a b le ^ 8 ) .

Each o f

t h e s e e x p r e s s i o n s o f s i t e were p l o t t e d a g a i n s t t h e growing s e a s o n p r e c i p ­
i t a t i o n f o r a 11-year p e rio d .

From th e same d a t a , th e c o r r e l a t i o n

c o e f f i c i e n t s were d e r i v e d in o r d e r to g iv e a m a th e m a tic a l e x p r e s s io n of
th e g r a p h i c d a t a .

11.

The fo r m u la f o r t h e c o r r e l a t i o n c o e f f i c i e n t i s :
sum

xz

-

~
p
sum x -

(sum x) (sum z)
-------------— —--------n
(sum x ) 2

sum z

n
*

w h ere:

r
x
z
n

=
=
s

c o rre la tio n c o e ffic ie n t
h e i g h t o r d ia m e te r grow th
p r e c i p i t a t i o n o r te m p e r a tu r e
number o f o b s e r v a t i o n s

p

-

(sum z ) 2
n

167

R esu lts
The h e i g h t g ro w th o f t u l i p p o p l a r in b o th A rea X and A rea T i s v e ry
c l o s e l y c o r r e l a t e d to th e grow ing se a so n p r e c i p i t a t i o n as shown in
F i g u r e 28*

The a c c u m u la tiv e h e i g h t grow th and a c c u m u la tiv e grow ing

s e a s o n p r e c i p i t a t i o n were u sed f o r t h i s c o r r e l a t i o n *

This dependency

of h e i g h t g row th on p r e c i p i t a t i o n in "both a r e a s i s f u r t h e r v a l i d a t e d
"by an r v a l u e o f *989 f o r A rea X and a v a lu e of .993 f ° r A rea Y.

However,

i t i s s i g n i f i c a n t to n o te t h a t th e c u rv e f o r A rea Y d e v i a t e s r a t h e r
s h a r p l y from t h a t of A rea X.

Thus, i t can he c o n clu d e d t h a t a lth o u g h

h o t h a r e a s a r e l i n e a r l y dep en d en t upon grow ing s e a so n p r e c i p i t a t i o n ,
A rea Y i s n o t a s e f f e c t i v e i n i t s u t i l i z a t i o n o f r a i n f a l l as A rea X, as
e v id e n c e d by a s lo w e r gro w th r a t e *

T his i s f u r t h e r p ro o f of t h e f a c t

t h a t o t h e r f a c t o r s such as e v a p o r a t i o n , r e l a t i v e h u m id ity and s o i l m o is tu r e r e l a t i o n s a r e s u p p le m e n ta l to th e r e s u l t i n g poo r h e i g h t grow th
o f A re a Y.

S in c e th e w a t e r - h o l d i n g c a p a c i t y of A rea Y i s s i g n i f i c a n t l y

g r e a t e r t h a n t h a t o f A rea X, i t i s r e a s o n a b l e to assume t h a t as th e
m o i s t u r e - h o l d i n g c a p a c i t y o f th e s o i l s d e c r e a s e s , t h e r e i s an a p p a r e n t
dependency o f i n c r e a s e d h e i g h t grow th upon p r e c i p i t a t i o n o f t h e growing
season*

T h is c o n c l u s i o n i s in a c c o r d w ith th e f a c t t h a t t u l i p p o p l a r i s

a t r e e r e q u i r i n g n e i t h e r e x c e s s iv e nor d ro u g h ty s o i l - m o i s t u r e c o n d i t i o n s ,
f o r i t s b e s t h e i g h t growth*
As w ith h e i g h t g ro w th , th e a c c u m u la tiv e r a d i a l grow th of t u l i p
p o p l a r i s c l o s e l y c o r r e l a t e d to t h e a c c u m u la tiv e grow ing s e a s o n p r e c i p i ­
t a t i o n a s shown in F i g u r e 29-

T h is dependency o f r a d i a l g row th to

p r e c i p i t a , t i o n i s v a l i d a t e d by a c o r r e l a t i o n c o e f f i c i e n t of *979
A rea X and an r v a l u e of *710 f o r A rea Y.

The low er v a lu e f o r A rea Y

F ig .

2 8.

THE EFFECT OP ACCUMULATIVE CROWING SEASON
PRECIPITA TIO N ON THE HEIGHT GROWTH OF TU LIP POPLAR

230
210
190
170
150

Growing Season Precipitation

250

In Inches

(1 9 4 1 - 1 9 5 1 )

PRECIPITATIO:

110
90

Accumlative

130
AREA X

70
50

AREA Y

30
J_______ I_______ I_______I_______I---------- L

1941

42

43

44

45

46
Y ear

47

48

49

50

51

169

Fig• 29.

THE EFFECT OF ACCUMULATIVE GROWING SEASON
PRECIPITATION ON THE RADIAL GROWTH OF TULIP POPLAR

(1 9 4 1 - 1 9 5 1 )

- 2 .5
Accumulative

210

Width

190

1 .5

Ring

PR EC IPITA T IO N

150

of Annual

AREA X

170

in Tenth

130

110

Inches

""AREA Y

90
70
50
30

1041

42

43

44

45

46
Y ear

47

48

49

50

51

170

i n d i c a t e s t h a t d i a m e t e r grow th i s l e s s h ig h l y c o r r e l a t e d to p r e c i p i t a t i o n
t h a n h e i g h t g r o w th .

A lth o u g h th e s t a n d a r d d e v i a t i o n of th e c o r r e l a t i o n

c o e f f i c i e n t g iv e s a v a l u e o f o n ly 1 . 2 (w hich i s n o t a s i g n i f i c a n t d i f f e r ­
ence) , i f a g r e a t e r number of o b s e r v a t i o n s had been ma.de, a s i g n i f i c a n c e
may h av e be en fo u n d .

N e v e r t h e l e s s , th e d a t a o b t a i n e d h e r e i n d i c a t e t h a t

A rea I i s l e s s e f f e c t i v e in u t i l i z i n g p r e c i p i t a t i o n of th e growing s e a s o n
t h a n A re a X,

These f i n d i n g s a r e i n a c c o rd w ith t h e i n h e r e n t grow th

p a t t e r n f o r t u l i p p o p l a r as a f f e c t e d by o t h e r s i t e f a .c to r s in c o n ju n c t io n
w ith r a i n f a l l .
I n o r d e r to e x p r e s s more v i v i d l y th e e f f e c t s o f grow ing s e a s o n
p r e c i p i t a t i o n on r a d i a l g ro w th , a c u rv e was c o n s t r u c t e d to show th e
c o r r e s p o n d i n g r i s e and f a l l o f annua.l p r e c i p i t a t i o n w ith t h e i n c r e a s e
and d e c r e a s e o f r a d i a l growth*

T h is r e l a t i o n s h i p i s p r e s e n t e d in F ig u r e JO*

F or t h i s c u r v e , t h e a v e r a g e m onthly grow ing s e a s o n p r e c i p i t a t i o n i s
p l o t t e d a g a i n s t th e r a d i a l grow th o f A rea X and A rea Y.

The e f f e c t s o f

p r e c i p i t a t i o n on r a d i a l grow th a r e r a t h e r s t r i k i n g between th e y e a r s
1 9 ^2 -1 9 ^ 8 .

From I 9 U8 to 195!

c o r r e l a t i o n does n o t seem to be as c l o s e ;

i t i s s u rm is e d t h a t p o s s i b l e crown c l o s u r e and t r e e c o m p e t itio n may be
coming more c r i t i c a l as th e t r e e s g e t o l d e r .
The a n a l y s i s o f r i n g w id th and h e i g h t as shown in T ab le *4-8 b r i n g s
o u t some i n t e r e s t i n g f a c t s :
1.

B oth A rea X and A rea Y show most marked c o r r e l a t i o n between
w id th o f a n n u a l r i n g and p r e c i p i t a t i o n i n th e y e a r s 19^1-19^3•

2.

No d i r e c t c o r r e l a t i o n e x i s t s between r a d i a l o r h e i g h t g row th
and t o t a l a n n u a l p r e c i p i t a t i o n in e i t h e r Area X o r A rea Y.
T h is f a c t f u r t h e r v a l i d a t e s th e dependency of h e i g h t and
d ia m e te r grow th upon grow ing s e a s o n p r e c i p i t a t i o n .

171

F ig . 30*

THE EFFECT OF RAINFALL DURING THE GROWING
3EA30N ON THE RADIAL GROWTH OF TULIP POPLAR

13

«12
Width
Ring

AREA X

.2 0
.10

7

In c h e s

AREA Y

3
PR EC IPITA T IO N

2
1

42

43

44

45

46
Y ear

47

48

in Tenth

/

1941

of Annual

.4 0

49

50

1951

172
TABLE 4 3 .
RELATIONSHIP BETWEEN GROWING SEASON PRECIPITATION AND GROWTH OP TULIP
POPLAR FOR AREA X AND AREA Y
(19^1-51)

R a d ia l Growth
(T e n th in c h e s )
In c h e s
P re c ip ita tio n
Year

Growing
Season

19^1
42
^3
44
4 '3
46
^7
4s
^9
30
1951

26.9S
21. l4
30 M
15-77
2 3 .7 0
i s . 20
2 2 .1 0
1 8 .8 7
2 5 .1 5
2 1 . SI
2 5 .1 9

Avg . w id th
annual rin g

Accumu­
la tiv e

He ig h t Growth
(F eet )

Accumu­
la tiv e
Growth

Avg. a n n u a l
h e i g h t g row th

Y

X

Y

X

.235
.3 6 0
.3 6 5
.2k
.265
.135
.2 2
.1 6
.125
.1 1
.1 0

.05
.23
.235
.195
.13
.0 6 5
.1 2 5
.1 2
.0S5
.0 75
.0 5

.235
.6 0 0
.9 6 0
1 .2 0 0
1.465
1 .6 0 0
1.820
1.9S0
2 .1 0 5
2 .2 1 5
2 .3 1 5

.05
.280
.515
.710
.840
.905
1 .0 3 0
1.150
1.2 35
1 .3 1 0
I .3 6 0

3 .0
k.O
k.Q
3 .5
3 .5
4 .0
k.O
3 .5
3 .0
3 .0
3 .0

1 .0 0
2 .0 0
2 .5 0
2 .0 0
2 .0 0
1 .5 0
1 .5 0
1 .5 0
1 .5 0
1 .5 0
1 .0 0

2 ^ 9 . 3S

2.315

1 .3 6 0

3S.5

1 8.00

2 2 .6 7

.210

.1 2 0

3 .5

1 .6 0

X

27
4s
79
9k
118
136
15S
177
202
224
2^9

Y

Accumul a t ive
Growth
X
3 .0
7 .0
1 1 .0
1 4.5
1 8 .0
2 2 .0
2 6 .0
29.5
3 2 .5
3 5 .5
3 8 .5

Y
1 .0 0
8 .0 0
5 .5 0
7 .5 0
9 .5 0
1 1 .0 0
1 2 .5 0
14 .0 0
1 5.50
1 7 .0 0
18 .0 0

T o tal
Mean

3* No d i r e c t c o r r e l a t i o n a p p e a rs to e x i s t Between w id th o f a n n u al
r i n g o r h e i g h t g ro w th and t h e t o t a l w in te r p r e c i p i t a t i o n in
e ith e r area.
4.

The h i g h e s t p r e c i p i t a t i o n r e c o r d e d f o r any one y e a r th ro u g h o u t
th e grow ing sea so n occurreo. in 19^3 *

C o r r e s p o n d in g ly , t h i s

same y e a r shows th e g r e a t e s t r i n g w id th f o r "both A rea X and
A rea Y.

A ls o , 19^3 e x h i b i t s th e g r e a t e s t p r e c i p i t a t i o n

d e p a r t u r e from normal th a n any o t h e r y e a r f o r th e 1 1 -y e a r
p e rio d *

173

5 * The h ig h e s t grow ing sea so n p r e c ip it a t i o n t o t a l recorded fo r
any th r e e c o n s e c u tiv e y e a rs occurred in 19^1-19^2-19^3, a
t o t a l o f 7^.59 in c h e s , which r ep re sen ts 31 p ercen t o f th e
e n t ir e growing season p r e c ip it a t i o n fo r th e 1 1 -y ea r p e r io d .
A c co r d in g ly , th e w idth o f annual r in g f o r the same 3 -y e a r
p e r io d f o r Area X was k2 p ercen t o f th e t o t a l w idth l a i d
down; Area Y l a i d down 37 p ercen t o f th e t o t a l r in g w idth
fo r th e same p e r io d .

The peak y ear o f 19^3 I s g r a p h ic a lly

shown in F igure 30 *
T em peratu re
From T a b le ^7 t h e s t r i k i n g u n i f o r m i t y in te m p e ra tu re o f t h e growing
s e a s o n f o r a 1 1 - y e a r p e r i o d c an be s e e n .

The mean te m p e r a t u r e s f o r a l l

y e a r s c o n s i d e r e d does n o t v a ry o v e r t h r e e d e g re e s f o r any one y e a r .

This

u n i f o r m i t y o f te m p e r a t u r e i s f u r t h e r v a l i d a t e d by c o r r e l a t i o n c o e f f i c i e n t s
o f .9 98 and .999 f o r t h e h e i g h t grow th o f A rea X and A rea Y r e s p e c t i v e l y .
The d ia m e te r g ro w th f o r th e same p e r i o d e x h i b i t s r v a lu e s o f .998 and .97^
f o r A re a X and A re a Y.

From th e s e v a lu e s th e co m plete and n e a r l y p e r f e c t

l i n e a r dependency o f h e i g h t and d ia m e te r grow th to grovzing sea so n tem pera­
t u r e can be shown.

A lth o u g h th e m a th e m a tic a l e x p r e s s io n of g ro w th p o r t r a y s

th e dependency o f g ro w th upon any c l i m a t i c e le m e n t, i t does n o t show th e
e f f e c t i v e u se of t h a t e le m e n t.

Thus, as shown in F ig u r e 31, t h e c u rv e s of

h e i g h t g ro w th f o r b o t h A rea X and A rea Y d e v i a t e from th e te m p e ra tu re
c u rv e a t a r a p i d r a t e .

Area Y, f o r exam ple, d e v i a t e s from th e te m p e ra tu re

c u rv e a t a more r a p i d r a t e th a n A rea X.

By p l o t t i n g th e a v e ra g e m onthly

te m p e r a t u r e o f t h e grow ing sea so n a g a i n s t any one y e a r o f th e 11 —y e a r

Ilk
P ig*

3 1 .

THE EFFECT OF A1 CU7-TULATIVE OROWINOSEASON TEMPERATURE ON THE HEIGHT GROWTH OF
TU LIP POPLAR
(1 9 4 1 - 1 9 5 1 )

Acctazrulative Average Growing Season Tenperature

In F1

700

600

T e m p e ra tu re

500

- 40

400

300

A re a X

200
A re a Y

-

100

1
1941

2

3

5
Y ears

6

7

8

9

10

11
1^51

12

175

p e r i o d , t h e c o r r e s p o n d i n g r i s e and f a l l in te m p e r a tu r e i s c o r r e l a t e d w ith
i n c r e a s e o r d e c r e a s e of th e r a d i a l growth*

This r e l a t i o n s h i p i s shown in

F ig u re 3 2 .
T hu s, a l t h o u g h "both a r e a s a r e l i n e a r l y d ep en d en t upon growing s e a s o n
t e m p e r a t u r e in g e n e r a l , th e dependency o f i n d i v i d u a l y e a r s a s e x p re s s e d
"by h e i g h t o r d ia m e te r g ro w th i s l e s s marked.

T em perature does n o t show

such w ide l o c a l v a r i a t i o n s as a r e e x h i b i t e d by p r e c i p i t a t i o n .

A reg res­

s i o n l i n e o f t h e v a l u e s in F i g u r e 32 f o r r a d i a l grow th and te m p e ra tu re
would show a v e ry d e c id e d n e g a t i v e c o r r e l a t i o n between te m p e r a tu r e and
growth*

T h is r e v e a l s t h a t in c r e a s e d te m p e ra tu re augments t r a n s p i r a t i o n

and c o n s e q u e n tly h a s t h e same u l t i m a t e e f f e c t a s a d e c r e a s e d w a te r s u p p ly .
As shown in a s tu d y by D i l l e r (193^) » h ig h te m p e ra tu re due to i t s e f f e c t
upon t r a n s p i r a t i o n w ould, where t h e w a te r s u p p ly is a l i m i t i n g f a c t o r ,
i n t e n s i f y th e e f f e c t o f low r a i n f a l l and p a r t i a l l y n u l l i f y th e b e n e f i c i a l
e f f e c t of h ig h r a i n f a l l *

Thus, a low s o i l m o is tu r e s u p p ly c o u p le d w ith

h i g h te m p e r a t u r e s d u r in g t h e grow ing s e a s o n would become e f f e c t i v e in
l i m i t i n g gro w th as a r e s u l t o f th e c lo s e r e l a t i o n between t u r g i d i t y o f
th e t r e e and g ro w th .

These f a c t s would t e n d to p o i n t o u t t h a t tem pera­

t u r e e f f e c t s a r e b e i n g masked by some o t h e r f a c t o r , such as grow ing
season p r e c i p i t a t i o n .

F u r t h e r e x p r e s s i o n o f th e e f f e c t s o f te m p e ra tu re

a s shown by s e a s o n a l e v a p o r a t i o n , r e l a t i v e h u m id ity , and s o i l - m o i s t u r e
r e l a t i o n s h i p s w i l l be c o n s id e r e d l a t e r .
From t h e f i n d i n g s above, te m p e ra tu re a p p e a rs to be a f f e c t i n g th e
g ro w th o f t u l i p p o p l a r i n d i r e c t l y by i t s e f f e c t on o t h e r c l i m a t i c f a c t o r s .
High t e m p e r a t u r e s a t c r i t i c a l p e r i o d s o f th e growing s e a s o n w i l l a f f e c t
th e r e l a t i v e h u m id ity , s o i l and a i r t e m p e r a t u r e s , and th e r a t e o f s o i l -

176
F ig .

32.

THE EFFECT OF AVERAGE MONTHLY TEMPERATURE
DURING THE GROWING SEASON ON THE RADIAL GROWTH OF
TULIP POPLAR

(1 9 4 1 - 1 9 5 1 )

H*
ct*
U'
.4 0 &

o
a

.3 0
/”
&<
£

$I70

.2 0 R

A rea X
A rea Y

.10 o

■ -3

w

.00

a

65
T e m p e ra tu re

I
&

60

I_________ |_________ I_________ I_________ I

!
1941

2

3

4

5

____ 1-------------- 1-------------- 1-------------- 1-------------- 1-------------- L -

6
Y ears

7

3

0

io

11
1951

£

177

m o istu re e v a p o r a tio n .

The tem perature e f f e c t s on h e ig h t growth are

p rob ab ly more c l o s e l y r e la t e d to s o i l d rain age and a v a ila b le s o il-m o is tu r e
than to th e d ir e c t e f f e c t o f p h o to s y n th e tic a c t i v i t y upon t u li p p o p la r .
However, t h i s assum ption can be fu r th e r dem onstrated by th e r e s u l t s o f
d ata tak en d a il y throughout two growing se a so n s, 1951

1952, which

f o llo w .
Thus, i t can be concluded th a t th e h e ig h t and r a d ia l growth o f
t u l i p p o p la r in Area X and Area Y seems to be jiore c lo s e ly c o r r e la te d
to growling season p r e c ip it a t io n and i t s atten d a n t s o il-m o is tu r e e f f e c t s
than to v a r ia t io n s in tem perature o f th e growing season throughout a
11-y e a r p e r io d .

178

R a d i a l Growth o f T re e s in th e A d jo in in g Qld-Growth Hardwood

I n c re m e n t "borings were ta k e n on t u l i p p o p l a r and o t h e r t r e e s p e c ie s
in

an e f f o r t to compare th e r a d i a l grow th of th e e x u e r im e n ta l p l a n t a t i o n

w i t h t h e r a d i a l g row th o f t r e e s in o ld —grow th a s s o c i a l io n s .

Ring v i& th

c a l c u l a t i o n s were made on t h e s e c o r e s f o r th e same p e r i o d 19 ^-1 -19 51 as
f o r t h e p l a n t a . t i o n —grown t u l i p p o p l a r .

In s e le c tin g th ese tr e e s f o r

in c re m e n t b o r i n g s , s e v e r a l t r e e s were b o re d which were s i m i l a r in age
and d i a m e t e r to t h e e x p e r im e n ta l t u l i p p o p l a r .

By comparing th e r a d i a l

gro w th o f t h e p l a n t a t i o n t u l i p p o p l a r w ith t r e e s in th e o ld -g r o w th woods,
some e s t i m a t i o n o f th e e f f e c t s o f p r e c i p i t a t ion upon r a d i a l grow th c o u ld
be

o b ta in e d .

S in c e grow ing s e a s o n p r e c i p i t a t i o n has th u s f a r been shown

to

be c l o s e l y c o r r e l a t e d to r a d i a l and h e i g h t grow th o f t u l i p

p o p l a r in

th e e x p e r im e n t a l a r e a , an i n v e s t i g a t i o n was made to f i n d o u t i f s i m i l a r
c o r r e l a t i o n s e x i s t e d in th e a d j o i n i n g o ld -g r o w th woods.

R a d ia l grow th

in r e l a t i o n to grow ing s e a s o n p r e c i p i t a t i o n wa.s t h e o n ly c o r r e l a t i o n
a t t e m p t e d ; t h i s a p p ro a c h would t r y to s u b s t a n t i a t e th e e f f e c t s o f p r e ­
c i p i t a t i o n in p l a n t a t i o n - g r o w n t u l i p p o p l a r as compared to f o r e s t - g r o w n
tre e s.
R esu lts
From th e r e s u l t s o f c u rv e s c o n s t r u c t e d from in crem en t c o r e s as
shown in F ig u r e 33, t h e r e l a t i o n s h i p of r a d i a l grow th to p r e c i p i t a . t i o n
can be o b s e r v e d th ro u g h o u t an 1 1 -y e a r p e r i o d .

These increm en t b o r in g s

were ta k e n on t r e e s whose a s s o c i a t e s in c lu d e d b e e c h , s u g a r m aple, b la c k
c h e r r y , r e d oak, w h ite oak, b la c k o ak , and dogwood.

By c o n t r a s t i n g

p r e c i p i t a t i o n w i t h t h e c u rv e s o f th e s i x t r e e s m easured, i t i s i n t e r e s t i n g

FIs. 33.
RADIAL GROV.'TH IK RELATION TO G-ROKINO IEA30N
PRECIPITA TIO N FOR TREES IN OLD-GrRORTH HARDROOD3

n7Q

Precipitation

in Inches

Width of Annual King in Tenth Inches

(1 9 4 1 - 1 9 5 1 )

10

-

10

-

10

-

10

-

T u lip
P o p la r
3 .2 " dbh

T u lip
P o p la r
1 3 .0 " d b h

B eech
5 .1 " dbh

.1 0 -

20
15

P re c ip ita tio n

1
1941

2

3

4

5

6
Years

7

8

Q

10

11
.1951

ISO

to n o t e t h a t none o f th e c u rv e s c o r r e l a t e c l o s e l y w ith p r e c i p i t a t i o n .
This r e s u l t i s in c o n t r a s t to th e m arkedly c l o s e c o r r e l a t i o n o f p l a n ­
t a t i o n —grown t u l i p p o p l a r and grow ing s e a s o n p r e c i p i t a t i o n .

The

f o l l o w i n g s t a t e m e n t s can "be made c o n c e rn in g t h e s e r e l a t i o n s h i p s :
1.

T u lip p o p l a r , "beech, and s u g a r maple grow ing in o ld -g r o w th
f o r e s t a s s o c i a t i o n s a d j o i n i n g th e p l a n t a t i o n do n o t
e x h i b i t a c lo s e r e l a t i o n s h i p to grow ing sea so n p r e c i p i ­
t a t i o n a s shown by in c re m en t c o re s th ro u g h o u t a 1 1 -y e a r
p e r i o d ( F ig u r e 3 3 )•

2.

The w id th o f a n n u a l r i n g o f t h e above t h r e e s p e c i e s i s
e v id e n c e t h a t o t h e r f a c t o r s a r e masking th e e f f e c t o f
p r e c i p i t a t i o n , a s e x p r e s s e d in r i n g w id th .

3.

T u lip p o p l a r fo u n d growing in o ld -g r o w th f o r e s t a s s o c i a ­
t i o n s i s l e s s c l o s e l y dep en den t upon p r e c i p i t a t i o n f o r
i t s d ia m e te r grow th th a n t u l i p p o p l a r grown in p l a n t a ­
t i o n s o f th e ty p e h e r e i n v e s t i g a t e d .

U.

I t is s u rm is e d t h a t d ia m e te r grow th o f t u l i p p o p l a r in
o ld - g r o w th f o r e s t s i s g r e a t l y a f f e c t e d by th e d e n s i t y and
age o f t h e s t a n d , w h ereas t u l i p p o p l a r in p l a n t a t i o n grown s i t e s (where age and d e n s i t y a r e c o n s ta n t) shows a
c l o s e c o r r e l a t i o n to d ia m e te r and t h e grow ing se a so n
p re c ip ita tio n .

181

The E f f e c t o f S u n s c a ld in R e l a t i o n to H eight G-rowth

O b s e r v a tio n o f t u l i p p o p l a r t r e e s grow ing in A rea Y (p o o r h e i g h t
g ro w th ) shows t h a t t h e s e t r e e s a r e damaged by extrem e s u n s c a ld ( F ig u r e s
3^

3^) *

S in c e i t i s p o s s i b l e t h a t th e c a s u a l o b s e r v e r m ight i n t e r ­

p r e t t h i s damage i n te rm s of re d u c e d h e i g h t g ro w th f o r A rea Y, a s tu d y
was c a r r i e d o u t to d e te r m in e what e f f e c t s u n s c a l d m ight have upon h e i g h t
g ro w th .

T re e s l o c a t e d on t h e s o u t h e r n and w e ste rn s i d e s o f th e " i n f l u e n c e

l i n e " a r e v i r t u a l l y f r e e from s u n s c a ld damage*

I n p r a c t i c a l l y e v ery c a s e ,

t h e s u n s c a l d is t h e r e s u l t of in c id e n c e from a so u th w est d i r e c t i o n
( F i g u r e 35)*

I* i s n o t th e o b j e c t o f t h i s s tu d y to i n v e s t i g a t e t h e c au se

o r s e t o f c ir c u m s ta n c e s which c o n t r i b u t e d to t h e damage.

A lth ou gh a

number o f h y p o th e s e s have been c o n j e c t u r e d as a r e a s o n f o r t h i s s u n s c a l d ,
i t i s s u f f i c i e n t to i n t e r p r e t th e r e s u l t s in term s o f h e ig h t g ro w th ,
s i n c e t h i s i s t h e p rim e o b j e c t i v e of t h e d i s s e r t a t i o n .
D ire c t E ffe c ts
S e v e r a l t r e e s were f e l l e d and s e c t i o n e d i n A rea Y where th e damage
i s e x tre m e .

M acro scop ic e x a m in a tio n of th e a n n u a l r i n g s , p l u s e v id e n c e

r e c e i v e d by l o c a l r e s i d e n t s , d i s c l o s e s t h a t t h e damage o c c u r r e d in 19 *+7 »
F ig u r e 3 5 .

W ith th e y e a r of o c c u r r e n c e h a v in g th u s been e s t a b l i s h e d , th e

h e i g h t g ro w th c u r v e s ( F i g u r e s 23 and 2h) were examined.

The c u rv e of

a n n u a l h e i g h t a g a i n s t grow th r a t e f o r 13k~[ and 19^8 i n d i c a t e s no v a r i a t i o n
w h a tso e v e r from t h e norm al u n ifo rm r a t e o f grow th f o r A rea Y.

I f th e

s u n s c a ld damage had been c o n t r i b u t i n g d i r e c t l y to h e i g h t g ro w th r a t e ,
th e n one m ight e x p e c t a d e v i a t i o n o r f l u c t u a t i o n in th e g row th r a t e c u rv e .
No ex trem e b r e a k o r d ip in th e g ro w th c u rv e i s n o te d in A rea Y f o r

or

182

Pig. 3^.
A c lo s e u p view o f s u n s c a ld damage o c c u r r in g in Area Y.
The t r e e shown above i s ^ . 2 in c h es in d ia m e te r ( d . b . h . ) .
E x te n s iv e s p r o u t i n g has o c c u r r e d a t th e b a se of th e t r e e as
a r e s u l t o f s u n s c a ld and t r e e c r i c k e t a c t i v i t y ; n o te th e
extrem e t a p e r from b a se o f th e t r e e to d . b . h . F u ng i have
a t t a c k e d t h e cambium and b a r k on th e so u th w est s i d e o f th e
b o l e . Evidence i n d i c a t e s no d i r e c t c o r r e l a t i o n o f s u n s c a ld
to th e r a t e o f h e i g h t g ro w th .

183

A rea o f
I n c i p i e n t D e cay

A re a o f
A d v a n c e d D ecay

S u n s c a ld 1 9 4 7

U n h e a le d A r e a

/v
A r e a Y - S t a t i o n IV
N a tu r a l S iz e
Age a t c r o s s s e c t i o n :
11 y e a r s
H e ig h t o f c r o s s s e c t i o n
ab o v e g ro u n d l e v e l :
16 In c h e s

DIAGRAMMATIC REPRESENTATION OF STEM CROSS SECTION
SHOWING DATE OF SUNSCALD IN RELATION
TO DIRECTION OF INCIDENCE

F ig . 3 5 .

izk

1 9^8.

D a ta b a s e d upon th e g row th c u rv e shows t h a t t h e a v e r a g e a n n u a l

h e i g h t g ro w th f o r 19^7 and 19^g was 1 .5 and 1 .5 f e e t r e s p e c t i v e l y .

This

r a t e o f g ro w th f o r t h e s e y e a r s i s in l i n e w ith th e c o n tin u o u s and u n ifo rm
r a t e o f g ro w th p r e c e d i n g and f o l l o w i n g 19^7*

Thus, e v id en c e b a se d upon

g ro w th r a t e and a c t u a l h e i g h t measurement c l e a r l y r e v e a l s t h a t s u n s c a ld
had no d i r e c t e f f e c t upon th e r a t e of h e ig h t grow th in th e a r e a where
damage o c c u r r e d .
The b a r k s,nd cambium on th e s o u th w e s t s i d e of t u l i p p o p l a r t r e e s in
A rea Y h av e b e e n s e r i o u s l y damaged i n many i n s t a n c e s ( F ig u r e 3 U ).

Damage

to t h e s e t r e e s h a s r e s u l t e d in p r o f u s e s p r o u t i n g a t th e b a s e o f th e t r e e s ,
a. r e s u l t o f s u n s c a l d and t r e e c r i c k e t a c t i v i t y .

In d ire c t E ffe cts
I n te rm s o f i n d i r e c t e f f e c t s o f s u n s c a l d , c e r t a i n f u n g i have
in v a d ed t h e sapwood th r o u g h c r a c k s in t h e b a r k which dev elo p a f t e r th e
stem s a r e damaged.

Two main f u n g i have been i d e n t i f i e d a s P o ly p o ru s
1p
t u l i p i f e r u s and P l e u r o t u s o s t r e a t u s .
The f i r s t o f t h e s e f u n g i i s by
f a r t h e more p r e v a l e n t o f th e two.

As a r e s u l t of th e a c t i o n o f t h e s e

f u n g i , f a i r l y e x t e n s i v e wind b re a k a g e h a s o c c u r r e d ( F ig u r e 3 6 ) in p o r t i o n s
o f A re a Y.
S in c e s u n s c a l d f a i l e d to o c c u r in A rea X, s o u th and w est o f th e
’’i n f l u e n c e l i n e , "

i t i s obv io us t h a t th e s h a d o w e f f e c t c au se d by th e

p r e s e n c e o f th e o l d gro w th hardwoods must have c o n t r i b u t e d i n some manner

12.

I d e n t i f i e d b y P r o f e s s o r F o r r e s t S tr o n g , B otany and P l a n t
P a th o lo g y D e p artm en t, M ichigan S t a t e C o lle g e , E a s t L a n s in g ,
M ich ig an .

185

Fig. 36.
A view ta k e n in A rea Y showing th e i n d i r e c t e f f e c t o f
s u n s c a l d , w i t h su b se q u e n t wind b re a k ag e caused by f u n g i
w eakening t h e ste m s. E x te n s iv e b a s a l s p r o u t i n g h a s o c c u r re d
in v i r t u a l l y a l l t r e e s e x h i b i t i n g s u n s c a ld damage. T h is b a s a l
s p r o u t i n g i s th e r e s u l t o f s u n s c a ld and t r e e c r i c k e t a c t i v i t y ,
e i t h e r in c o m b in a tio n o r s i n g l y .

l g6

to th e com plete ab sen ce o f su n sc a ld in t h is a r e a .

However, the su n sca ld

damage in Area. Y can be in te r p r e te d a,s an in d ir e c t index o f the e f f e c t
upon h e ig h t grow th.

Thus, Area Y has g r e a te r exposure from in c id e n t

so u r ce s o f h ea t and l i g h t , h igh er s o i l evap oration r a t e s , h ig h er a ir
tem peratures and low er r e l a t i v e h u m idity, and high er wind v e l o c i t i e s
than Area X.

These in d ir e c t e f f e c t s , or f a c t o r s of s i t e , in r e la t io n

to h e ig h t growth w i l l be taken up under m ic r o clim a tic in v e s t ig a t io n s
and fu r th e r s u b s ta n tia te d .

A lthough ra th er extreme damage has been

caused by th e su n sc a ld in Area Y, n e v e r th e le s s th e damage has r ev e a le d
a c lu e to oth er in d ir e c t im portant clim a .tic and edaphic c o n s id e r a tio n s
o f th e s i t e .

1S7

The H erbaceou s V e g e ta tio n a s R els/ted to S o i l M o istu re in A rea X and A rea Y

T hroughout t h e growing s e a s o n of 1952 * & s y s te m a tic t a l l y o f h e rb a ­
ceous s p e c i e s was t a k e n in b o t h a r e a s o f good and p o o r h e i g h t g ro w th .
P h o to g r a p h s o f th e gro un d v e g e t a t i o n were o b ta in e d th ro u g h o u t t h e growing
s e a s o n i n o r d e r to o b s e rv e th e k i n d o f v e g e t a t i o n p r e s e n t in s u c c e s s i o n a l
sta g e s.

Many c l a s s i f i c a t i o n s o f f o r e s t s i t e s on th e b a s i s o f i n d i c a t o r

p l a n t s a p p e a r to be h i g h l y s u b j e c t i v e , b u t in a g e n e r a l way i t is re c o g ­
n i z e d t h a t r e l a t i o n s h i p s e x i s t betw een ground v e g e t a t i o n and s o i l m o istu re*
Thus, r a t h e r t h a n b e in g u sed as an i n d i c a t i o n o f s i t e q u a l i t y ,

in d ic a to r

p l a n t s a r e most u s e f u l i n t h i s s tu d y as an e x p r e s s io n o f s o i l m o is tu re
c o n d i t i o n s in two a d j o i n i n g a r e a s .

A ls o , p l a n t i n d i c a t o r s p e c i e s a r e

b e s t u s e d when d e a l i n g w ith n a t u r a l - g r o w n , m a tu r e .f o r e s t s ; th e p r e s e n t
s tu d y d e a l s w ith p l a n t a t ion-grow n t r e e s p e c ie s*

In d ic a to r v e g e ta tio n

h a s b e e n u s e d to a l i m i t e d e x t e n t in e v a l u a t i n g p l a n t i n g s i t e s .

In th is

s t u d y , no a t t e m p t i s b e in g made to group c l a s s e s of s i t e s on th e b a s i s
o f c o m p o s itio n o f t h e h e rb a c e o u s v e g e t a t i o n .

The main o b j e c t i v e o f th e

h e rb a c e o u s v e g e t a t i o n a l a n a l y s i s i s to show how th e s u c c e s s io n o f s p e c ie s
th r o u g h o u t t h e gro w in g s e a s o n r e l a t e to s o i l m o is tu re c o n d i t i o n s .
R esu lts
The p r e s e n c e o f h e rb a c e o u s s p e c ie s now a p p a r e n t softer a 1 5 -y e a r
s u c c e s s i o n a l p e r i o d in A rea X and Y is a u s e f u l c r i t e r i o n as to s o i l
m o i s t u r e r e l a t i o n s in each a r e a .

T a b le s ^9~51 &ive a l i s t i n g o f s p e c ie s

a c c o r d in g to p l e n t i f u l n e s s th ro u g h o u t th e growing s e a s o n of 1 9 5 2 *

I* i s

p o s s i b l e to f o l l o w th e s u c c e s s i o n o f an i n d i v i d u a l s p e c i e s o r genus
th r o u g h o u t th e e n t i r e grow ing s e a s o n , th u s a c h ie v in g some i n d i c a t i o n of

TABLE 4 9 .

188

THE GROWING- SEASON SUCCESSION OF HERBACEOUS SPECIES IN AREA X
AND AREA T

P Ie n tifu ln e ss C rite ria :
VA
A
0
R

*■* Very abundant
- Abundant
- O c c a s io n a l
- Rare

VERNAL ASPECT (MAT 20 - JUNE 20)
VA - Very abundant
A re a X (Good h e i g h t growth)
S p e c ie s

A rea T (P o or h e i g h t growth)
S p e c ie s

A cer saccharum Marsh *
V io la spp.
P o t e n t i l i a n o r v e g i c a L.
P o te n t i l i a r e c t a 1 .
Rubus id a e u s L.

T r if o liu m p r a t e n s e L.
T r i f o l i u m re p e n s L.
Rumex a c e t o s e l l a L.
P o te n t i l i a n o r v e g ic a L.
P o te n t i l i a r e c t a L.
Daucus c a r o t a L.
H ieracium a u ra n tia c u m L.
A c h i l l e a m i l l e f o l i u m L.
C erastium vulgatum L.
Poa com pressa L.
Abundant
Chrysanthemum leucanthemum L,
D an th o n ia s p i c a t a L.
A n te n n a r ia spp.

Daucus c a r o ta , L.
Galium spp*
Im p a tie n s p a l l i d a N u t t .
P a r t h e n o c i s s u s q u i n q u e f o l i a L.
0 - O c c a s io n a l
Ulmus f u l v a Michx. *
T r i f o l i u m p r a t e n s e L.
T r i f o l i u m r e p e n s L.
Taraxacum o f f i c i n a l e Weber.
Rhus to x ic o d e n d r o n L.
P la n ta g o m ajo r L.
A s c l e p i a s s y r i a c a L.
Geum c a n a d e n se J a c q .
Rumex a c e t o s e l l a L.
A c h i l l e a m i l l e f o l i u m L.
F r a g a r i a v i r g i n i a n a , Duchesne.
Poa c o m p ressa L.
Lepidium c a m p e s tre L.
L a p o r t e a c a n a d e n s is L.
H ydrophyllum ap pen d ic u la tu rn Michx
Cornus . f l o r i d a L.
Rhus t y p h i n a L.
Carex sp p .
R - R are

E r ig e r o n ramosus W alt.
Sonchus a r v e n s i s L.
Taraxacum o f f i c i n a l e Weber
Verbascum th a p s u s L.
A s t e r spp.
P o ly tric h u m commune Hedw.
L a c tu c a c a n a d e n s is L.

P ru n u s s e r o t i n a E hrh. *
Fagus g r a n d i f o l i a . Ehrh. *
B a r b a r e a v u l g a r i s R. B r.
D r y o p t e r i s marg i n a l i s L.
Hypericum p e r f o r a tu m L.
♦ S e e d lin g s

Prunus s e r o t i n a Ehrh. *
Acer saccharum Marsh. *
Ulmus f u l v a Michx. *
F r a g a r i a v i r g i n i a n a Duchesne
S e n e c io a u re u s L.

189

TABLE 50.
THE GROWING SEASON SUCCESSION ON HERBACEOUS SPECIES IN AREA X
AND AREA Y
EARLY ESTIVAL ASPECT (JUNE 20 - JULY 21)
VA - Very abundant
A re a X (Good h e i g h t growth)
S p e c ie s
A cer saccharum M arsh. *
Rubus id a e u s L.
P a r t h e n o c i s s u s q u i n q u e f o l i a L.

A rea Y (P oor h e i g h t growth)
S p e c ie s
Daucus c a r o t a L.
P o t e n t i l i a n o r v e g ic a L.
T r if o liu m p r a t e n s e L.
T r i f o l i u m re p e n s L.
Poa com pressa L.
Chrysanthemum leucanthemum L.
D a n th o n ia s p i c a t a L.

A - Abundant
Daucus c a r o t a L.
I m p a tie n s p a l l i d a N u t t .
P o t e n t i l i a n o r v e g i c a L.
P o t e n t i l i a r e c t a L.
V io la spp.
L a p o r t e a c a n a d e n s is L.
Galium sp p .

E r ig e r o n ramosus W alt.
H ieracium a u ra n tia c u m L.
A c h i l l e a m i l l e f o l i u m L.

0 - O c c a s io n a l
P o ly tric h u m commune Hedw.
Taraxacum o f f i c i n a l e Weber,
Verbascum th a p s u s L.
L a c tu c a c a n a d e n s is L.
Rumex a c e t o s e l l a L.
S o lid a g o n e m o ra lis A i t .
C ir c a e a l a t i f o l i a H i l l .
Cornus f l o r i d a L.

A s t e r sp p .
C r y p t o t a e n i a c a n a d e n s is L.
E r i g e r o n ramosus W alt.
T r i f o l i u m p r a t e n s e L.
P l a n t a g o m a jo r L.
Ulmus f u l v a Michx. *
Geum c a n a d e n se J a c q .
S a n i c u l a t r i f o l i a t a B ick n .
S o lid a g o n e m o r a lis A i t .
Taraxacum o f f i c i n a l e Weber.
Rhus t y p h i n a L.
A c h i l l e a m i l l e f o l i u m L.
L a c tu c a c a n a d e n s is L.
Chrysanthemum leucanthemum L.
R ud beckia h i r t a L.
Rhus to x ic o d e n d r o n L.
Poa c o m p ressa L.
R - Rare
Hypericum p e r f o r a tu m L.
F r a g a r ia , v i r g i n i a n a Duchesne.
P ru n us s e r o t i n a E hrh. *
Carex sp p .
Quercus v e l u t i n a Lam. *
J u g l a n s c i n e r e a L. *
Cary a, o v a t a M i l l . *
Lepidium c a m p e s tre L. *
* S e e d lin g s

Rhus ty p h in a L. *
J u g la n s c i n e r e a L. *
Carya o v a ta M i l l . *
Q,uercus v e l u t i n a Lam. *

190

TABLE 5 1 .
THE GROWING- SEASON SUCCESSION OP HERBACEOUS SPECIES IN AREA X
AND AREA T

MID - ESTIVAL ASPECT (JULY 31 - AUG.20)
VA - Very abundant
A re a X (Good h e i g h t growth)
S p e c ie s
P a r t h e n o c i s s u s q u i n q u e f o l i a L.

A rea Y (Poor h e i g h t growth)
S p e c ies
Daucus c a r o t a L.

A - Abundant
Rubus c a n a d e n s is L.
L a p o r t e a c a n a d e n s is L.
A cer saccharum M arsh. *
Im p a tie n s p a l l i d a N u tt.
A s t e r sp p .
P o t e n t i l l a n o r v e g i c a L.
P o t e n t i l i a r e c t a L.
C ir c a e a l a t i f o l i a H i l l .

A c h i l l e a m i l l e f o l i u m L.
H ieracium a u ra n tia c u m L.
P o te n t i l i a n o r v e g ic a L.
P o t e n t i l l a r e c t a L.
Poa com pressa L.
D a n th o n ia s p i c a t a L.
Hypericum p e r f o r a tu m L.
A s t e r sp p .
0 - O c c a s io n a l
Quercus v e l u t i n a Lam. *
P o ly tric h u m commune Hedw.
Taraxacum o f f i c i n a l e Weber
Ulmus f u l v a Michx. *
E r ig e r o n ramosus W alt.
Rhus t y p h in a L.
L a c tu c a c a n a d e n s is L.
Prunus s e r o t i n a Ehrh. *
P r u n e l l a v u l g a r i s L.
S o lid ag o n e m o ra lis A i t .

P ru n u s s e r o t i n a Ehrh. *
Ulmus f u l v a Michx. *
P l a n t ago m a jo r L.
A m brosia t r i f i d a L.
Daucus c a r o t a L.
Geum c a n a d e n s is J a c q .
P r u n e l l a v u l g a r i s L.
C arya o v a t a M i l l . *
V i o l a sp p .
L a c tu c a c a n a d e n s is L.
Rhus t y p h i n a L. *
Hypericum p e r f o r a tu m L.
O e n o th e ra b i e n n i s L.
R u d b ec k ia h i r t a L.
Pag us g r a n d i f o l i a Ehrh. *
T r i f o l i u m p r a t e n s e L.
E r ig e r o n ramosus W alt.
A s c le p io d o r a v i r i d i s W alt.
Q,uercus v e l u t i n a Lam. *
R - R are
R ib es c y n o s b a t i L.
Cornus f l o r i d a L.
* S e e d lin g s

R udbeckia h i r t a L.

191

i t s m o i s t u r e r e q u ir e m e n ts f o r a s p e c i f i c e n v iro n m e n t.

F u r t h e r e v id e n c e

o f t h e s p e c i e s p r e s e n t a t a p a r t i c u l a r s t a g e of s u c c e s s io n i s shown by
means o f q u a d r a t p h o to g ra p h s t a k e n a t t h e same p o s i t i o n th ro u g h o u t th e
gro w ing s e a s o n .
The most s t r i k i n g e v id e n c e o f th e d i f f e r e n c e in a v a i l a b l e s o i l
m o i s t u r e b e tw ee n A re a X and A rea Y is shown in F ig u r e s 37 and 3 8 .

A rea Y

p o s s e s s e s a d o m in a n tly g r a s s —weed a s p e c t th ro u g h o u t t h e e n t i r e growing
season.

A lth o u g h weed s p e c i e s o c c u r in A rea X, t h e s e s p e c i e s a r e much

l e s s a b u n d a n t t h a n i n A rea Y.

Such g e n e r a as V i o l a , I m p a tie n s ,

P a r th e n o c is s u s , G-alium, C irca ea , and Acer (s e e d lin g s ) are co m p letely
ab sen t in Area Y.
h a b it a t s .

These genera are u s u a lly in d ic a tiv e o f m oist

I n s te a d , in Area Y are found such dominant genera as A c h ille a ,

H ieraciu m , P oa, D anthonia, and P olytrich u m .

The l a t t e r gen era are

in d igen ou s to d r ie r s i t e s , or o l d - f i e l d a s s o c ia t io n s .

I t is n o te ­

worthy th a t a l l o f th e above named gen era are not t r a n s ie n t s , but p e r s is t
in th e s e two a rea s throughout th e growing season s u c c e s s io n .

Further

ev id e n c e o f th e c o n tr a s t in a v a ila b le s o il-m o is tu r e between Area X and
Area Y, as supplem ented by th e p resen ce o f herbaceous v e g e t a tio n , is
found under c lim a tic d ata o f t h i s t h e s i s .

A d e f i n i t e c o r r e la tio n appears

to e x i s t between the k in d o f herbaceous v e g e t a tio n p re se n t throughout the
grow ing s e a s o n , and th e p e r ce n t o f a v a ila b le s o i l m oisture a t a depth o f
s i x in c h e s a s ev id en ced by rea d in g s on Bouyoucos b lo ck s taken throughout
a s im ila r p e r io d .
Thus, th e p r e se n c e o f herbaceous v e g e ta tio n a s s o c ia te d w ith a s p e c i f i c
area i s fu r th e r supp lem en tal ev id en ce th a t a v a ila b le s o i l m oistu re is a
f a c t o r o f prim ary im portance in th e d i f f e r e n t i a l h e ig h t growth o f p la n ta ­
tion -grow n t u l i p p o p la r .

192

P ig . 3 7 .

T he v e r n a l a s p e c t

in A rea X (g o o d h e ig h t g r o w th ).

193

P ig .

38.

The v e r n a l a s p e c t

in A rea Y (p o o r h e ig h t g r o w th ).

13k

F ig . 39.

T he e a r l y e s t i v a l a s p e c t
g r o w th (A r e a X ) .

in th e a r e a o f good h e ig h t

195

IV

F i g . ^40.

T he e a r l y

e s t i v a l a s p e c t in th e a r e a o f p oor h e ig h t
groitfth (A rea, Y ) .

196

WiPjXSts:

F ig .

kl.

T he m id -

e s t i v a l a s p e c t in A rea Y

197

II

F ig . 42.

III

F ig . ^3 .
The e a r l y autum nal a s p e c t in A rea X ( above) and Area Y
( b e lo v ) .

198

Micro c l i m a t i c F a c t o r s i n R e l a t i o n to H e ig h t Growth o f
T u l ip P o p l a r in A rea X and A rea Y
D u rin g t h e grow ing s e a s o n s o f 1951 a^d 1952 s e v e r a l m i c r o c l i m a t i c
f a c t o r s were r e c o r d e d a t c l i m a t i c s t a t i o n s in th e a r e a s o f good and p o o r
h e i g h t g ro w th o f t u l i p p o p l a r .

Two s t a t i o n s were s e t up c l o s e to th e

o ld —g ro w th hardwood s t a n d and two s t a t i o n s were e s t a b l i s h e d f a r t h e r out
in t h e p l a n t a t i o n where th e h e i g h t grow th i s p o o r .

R eadings on a i r

te m p e ra tu re , e v a p o ra tio n l o s s , p e rc e n t a v a ila b le s o i l m o istu re , s o i l
s u r f a c e t e m p e r a t u r e , and r e l a t i v e h u m id ity were ta k e n d a i l y th ro u g h o u t
th e g ro w in g s e a s o n s .
t h e y e a r s 1951

These d a t a were th e n p l o t t e d f o r b o th a r e a s f o r

1 9 5 2 ; t h e r e s u l t s of t h i s mic ro c l i m a t i c s tu d y a r e

h e r e r e c o r d e d f o r t h e 1951 grow ing s e a s o n o n ly .
S in c e t h e w a te r economy o f young f o r e s t p l a n t a t i o n s i s d i r e c t l y
r e l a t e d to th e p h o to s y n th e tic a c t i v i t y of in d iv id u a l tr e e s ,

i t is c le a rly

a f a c t o r o f im p o rta n c e in g o v e rn in g t h e r a t e o f h e i g h t grow th o f t u l i p
p o p l a r u n d e r th e c l i m a t i c c o n d i t i o n s o f s o u th w e s te rn M ich ig an .

Thus,

from t h e r e s u l t s o b t a i n e d h e r e , i t a p p e a rs t h a t h e i g h t g ro w th of th e
t r e e s on two c o n t r a s t e d a r e a s i s c o n d i t i o n e d by f a c t o r s which a r e o b v i­
o u s ly a s s o c i a t e d w i t h w a te r u t i l i z a t i o n of th e t r e e .

Any o f t h e s e f a c t o r s

which a f f e c t t h e s o i l - m o i s t u r e regim e a r e r e f l e c t e d , in h e i g h t g ro w th and
o v e r a p e r i o d o f tim e w i l l d e f i n e th e s i t e q u a l i t y .

F o rtu n a te ly ,

in t h i s

i n v e s t i g a t i o n , th e a r e a o f good h e i g h t grov/th r e p r e s e n t s a " n a t u r a l
l a b o r a t o r y " w i t h th e p r e s e n c e o f o l d grow th woods on th e s o u t h and w est
a c t i n g a s a c o n t r o l in which c e r t a i n v a r i a b l e s have o p e r a te d th ro u g h o u t
a 1 5 -y ear p e rio d .

S in c e h e i g h t g ro w th v a r i e s w i t h t h e c l i m a t i c c o n d i t i o n s

199

o f t h e g ro w in g s e a s o n , assum ing o t h e r f a c t o r s a r e c o m p arab le , i t i s
p o s s i b l e t o c o r r e l a t e r a t h e r c l o s e l y th e grow th o f t u l i p p o p l a r and th e
m i c r o c l i m a t i c f a c t o r s a c t i n g upon t h i s g ro w th .

A gain, t h e s p a c in g and

age o f t h e t u l i p t r e e s in b o th A re a X and A rea T i s c o n s t a n t , adding
v a l i d i t y to th e i n v e s t i g a t i o n of th o s e f a c t o r s which a r e s u s p e c t e d o f
b e in g l i m i t i n g .

The m ic r o c l imat i c d a t a p r e s e n t e d h e r e a r e a g g r e g a te

v e r i f i c a t i o n of t h e f a c t t h a t a v a i l a b l e m o is tu r e i s th e p r im a r y l i m i t i n g
f a c t o r i n p r o d u c in g a d i f f e r e n t i a l h e i g h t grow th o f p l a n t a t i o n - g r o w n
tu lip p o p la r.

T h is i s n o t to imply t h a t t h e t u l i p t r e e s in th e a r e a o f

good h e i g h t g ro w th a r e n e c e s s a r i l y r e c e i v i n g g r e a t e r amounts o f m o i s t u r e ,
b u t r a t h e r t h a t t h e t r e e s in t h i s a r e a a r e a b l e to u t i l i z e t h e m o is tu r e
more e f f e c t i v e l y due to a s e t o f i n t e r r e l a t e d s i t e c o n d i t i o n s n o t fo un d
in A re a Y.

S ix m icro c l im a tic f a c t o r s a r e h e r e p r e s e n t e d g r a p h i c a l l y in

o r d e r to c o n t r a s t t h e c l i m a t i c c o n d i t i o n s o f two opp osing s i t e s o f p l a n t a ­
tio n - g r o w n t u l i p p o p l a r .

S in c e o n ly t h e m i c r o c l i m a t i c d a t a f o r 1951 a r ©

i n c l u d e d , i t was deemed a d v i s a b l e to d e l a y th e co m plete s t a t i s t i c a l
a n a l y s i s of t h e s e d a t a u n t i l th e t e r m i n a t i o n o f two grow ing s e a s o n s .

A

c o m p le te a n a l y s i s o f th e m ic r o c l im a tic data, w i l l be p u b l i s h e d a t a l a t e r
d a te .

N e v e r t h e l e s s , enough d a t a have b e en com piled to i n d i c a t e t h e t r e n d

o f c l i m a t e in t h e e x p e r im e n t a l a r e a ; d a t a f o r th e e a r l y grow ing s e a s o n o f
1952 i n d i c a t e t r e n d s s i m i l a r to t h o s e of 1951*

E v apo rat ion
The r a t e o f e v a p o r a t i o n was ta k e n d a i l y th ro u g h o u t t h e grow ing s e a s o n
in b o t h A rea X and A rea Y u t i l i z i n g th e now w ell-know n L i v i n g s t o n atm om eter
b u lb .

T h is d e v ic e was used to show in an i n d i r e c t manner t h e r e l a t i v e

r a t e s and i n t e g r a t e d e f f e c t of wind movement, h u m id ity and a i r te m p e r a tu r e

Number

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in e a c h a r e a .

The e v a p o r a t i o n s t r e s s o f th e atm o sp h ere as a f f e c t e d by

th e above f a c t o r s i s o f g r e a t im p o rtan c e to grov/th of p l a n t s .

The

a tm o m e ters w ere p l a c e d on t h e f o r e s t f l o o r i n o r d e r to a s c e r t a i n th e
e v a p o ra tio n lo s s a t th is l e v e l .

I n t h i s s t u d y , t h e l o s s o f w a te r from

t h e s o i l s u r f a c e i s o f p rim e im p o rtan c e as an in d e x to s o i l m o is tu r e
e v a p o r a t i o n and d e te r m in e s t h e e f f i c i e n c y o f r a i n f a l l to a g r e a t d e g r e e .
The e v a p o r a t i o n l o s s f o r A rea X and Area T i s shovm. in F ig u r e ^t-U.
I t i s a p p a r e n t from th e r e s u l t s o b t a i n e d h e r e t h a t th ro u g h o u t th e e n t i r e
grow ing s e a s o n , t h e w a te r l o s s i s g r e a t e s t in A rea Y.

The g r e a t e s t l o s s

d i f f e r e n c e betw een t h e two a r e a s o c c u r s a t t h e most c r i t i c a l h e i g h t
g ro w th p e r i o d ( J u l y ) f o r t h i s a r e a .

Thus, a t a tim e when t u l i p p o p l a r

i s a t t h e peak o f i t s h e ig h t grov/th, A rea Y has th e g r e a t e s t e v a p o r a tio n
lo ss.

The m i c r o c l i m a t i c en viron m en t f o r A rea X, w i t h r e g a r d to e vap ora­

tio n ,

i s o b v i o u s l y one more s u i t a b l e to th e b e t t e r h e i g h t g ro w th o f t u l i p

p o p la r.
R e l a t i v e H um idity
The r e l a t i v e h u m id ity was m easured d a i l y th ro u g h o u t t h e growing
s e a s o n in b o t h a r e a s .
a s p i r a t e d p s y c h r o m e te r .

H um idity r e a d in g s were ta k en by means o f a han d These v a l u e s a r e shown in F ig u r e *+5*

The r e l a t i v e h u m id ity i s c l o s e l y r e l a t e d to t h e r a t e o f w a te r l o s s
from a f r e e w a te r s u rfa .c e o r from a p l a n t .
t u r e and th e amount o f m o is tu r e p r e s e n t .

I t i s d e p en d e n t upon tem pera­
Thus, e v e ry change in te m p e r a tu r e

r e s u l t s i n a change in r e l a t i v e h u m id ity and a c o n se q u e n t a l t e r a t i o n of
ev ap o ratio n or tr a n s p ir a tio n .

The r e s u l t s o f th e p r e s e n t s tu d y show low er

r e l a t i v e h u m i d i t i e s th ro u g h o u t t h e growing s e a s o n in th e a r e a o f p o o r
h e i g h t g r o w th .

I n d i r e c t l y , t h i s i n d i c a t e s h i g h e r te m p e r a t u r e s in A rea Y,

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so t h a t w a te r e x p o se d q u ic k ly e v a p o r a te s and t h e more r a p i d l y t h e a i r
w i l l t a k e up w a te r from t r a n s p i r i n g l e a v e s o r from a m o is t s o i l s u r f a c e .
T hese r e s u l t s a r e c o r r e l a t e d w i t h t h e h ig h e v a p o r a t i o n r a t e , h i g h e r s o i l
s u r f a c e t e m p e r a t u r e s and h i g h a i r t e m p e r a t u r e s o f th e p o o r h e i g h t g ro w th
a re a *

The h i g h e r te m p e r a t u r e o f A rea T i n c r e a s e s t h e c a p a c i t y o f th e a i r

f o r m o i s t u r e and c o n s e q u e n tly lo w e rs th e r e l a t i v e h u m id ity ; th e o p p o s i t e
s i t u a t i o n e x i s t s i n A re a X.

A i r T em perature
A i r t e m p e r a t u r e s were r e c o r d e d d a i l y th ro u g h o u t th e grow ing se a so n
hy means o f a s l i n g p s y c h r o m e te r.

The v a lu e s o b t a i n e d f o r b o th a r e a s

a r e s h o r n in F i g u r e ^ 6 .
The r e s u l t s show h ig h e r te m p e r a t u r e s in A rea Y th ro u g h o u t t h e e n t i r e
grow ing s e a s o n .

T his c l e a r l y shows t h e more exp osed p o s i t i o n , h ig h e r

e v a p o r a t i o n r a t e , low er r e l a t i v e h u m id ity , and h ig h e r s u r f a c e te m p e r a tu r e
o f t h e p o o r h e i g h t g ro w th a r e a .

The g ra p h o f a i r te m p e r a tu r e c l e a r l y

i n d i c a t e s t h e h i g h e r a i r te m p e r a t u r e o f A rea Y in th e c r i t i c a l p e r i o d of
g ro w th f o r t u l i p p o p l a r .

The in c r e a s e d te m p e ra tu re of A rea Y th u s

p ro m o tes g r e a t e r t r a n s p i r a t i o n and e v a p o r a tio n a t a tim e when t u l i p p o p l a r
r e q u i r e s more re d u c e d te m p e r a t u r e s .
S u r fa c e S o i l Tem perature
The te m p e r a t u r e o f th e s o i l s u r f a c e was ta k e n d a i l y th ro u g h o u t th e
grow ing s e a s o n by means of a s o i l th e rm o m e te r.

The s t r i k i n g r e s u l t s a r e

g i v e n f o r b o t h A rea X and A re a Y in F i g u r e *+7A m a rkedly h i g h e r grow ing s e a s o n s o i l s u r f a c e te m p e r a tu r e is r e v e a l e d
in A re a Y th a n in A rea X.

T h is h ig h s u r f a c e te m p e r a tu r e e x e r t s an i n d i r e c t

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e f f e c t "by i n c r e a s i n g e v a p o r a tio n l o s s from t h e s o i l ,

A c o rre la tio n

a p p e a r s to e x i s t i n t h i s s tu d y "between t h e h e rb a c e o u s v e g e t a l io n ty p e
and t h e s u r f a c e s o i l t e m p e r a t u r e , w ith i t s s u b s e q u e n t r a p i d s u r f a c e s o i l
m o istu re lo ss*

I t i s a p p a r e n t t h a t th e more exposed s i t u a t i o n o f A re a Y

r e s u l t s i n g r e a t e r e v a p o r a t i o n l o s s and d r i e r c o n d i t i o n s th ro u g h o u t th e
p e r i o d o f g ro w th t h a n A rea X.

A gain, t h e g r e a t e s t d i f f e r e n c e in s o i l

s u r f a c e t e m p e r a t u r e betw een b o th a r e a s o c c u r s a t th e c r i t i c a l h e i g h t
g ro w th p e r i o d o f t u l i p p o p l a r .

P e r c e n t A v a i l a b l e M o istu re
T hroughout th e gro w ing s e a s o n , d a i l y s o i l m o is tu re m easurem ents were
ta k e n by means o f Bouyovicos b lo c k s a t d e p th s o f s i x and e i g h t e e n in c h es
re sp e c tiv e ly .
and 1+9•

The r e s u l t s o f t h e s e f i n d i n g s a r e shown i n F ig u r e s Us

At a d e p th o f s i x i n c h e s , A rea Y shows a m arkedly low er a v a i l a b l e

m o i s t u r e c o n t e n t th ro u g h o u t th e grow ing s e a s o n th a n in A rea X.

This r e s u l t

i s o f p rim e im p o r ta n c e , s i n c e i t h a s been shown p r e v i o u s l y t h a t s o i l s in
A re a Y p o s s e s s h i g h e r w a t e r - h o l d i n g c a p a c i t i e s and c l a y c o n te n t th a n A rea X.
Thus, d e s p i t e a s i g n i f i c a n t t e x t u r a l s o i l d i f f e r e n c e betw een th e two a r e a s ,
th e p e r c e n t of a v a i l a b l e s o i l m o is tu r e a t th e e f f e c t i v e r o o t zone d e p th i s
g r e a t e r in A re a X.

T h is i s f u r t h e r v a l i d a t i o n o f th e f a c t t h a t s o i l s i n

A rea Y have a h i g h e r w a t e r - h o l d i n g c a p a c i t y b ased upon m e c h a n ic a l a n a l y s i s ,
y e t l o s e w a te r a t a f a s t e r r a t e th a n A rea X.

I t i s a p p a r e n t from t h e s e

f i n d i n g s t h a t t h e e f f e c t i v e u t i l i z a t i o n o f a c o n tin u o u s w a te r s u p p ly i s
g r e a t e s t in th e a r e a o f good h e i g h t g ro w th .
At a d e p th o f e i g h t e e n i n c h e s , Area Y has a g r e a t e r a v a i l a b l e m o is tu r e
c o n t e n t i n t h e e a r l y s o r i n g and e a r l y autumn th a n does A rea X.

T h is r e s u l t

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i s a p p aren tly * due t o t h e f a c t t h a t t h e w a te r t a h l e l e v e l i s c l o s e r to th e
s u r f a c e i n A re a Y a t t h e s e p e r io d s #
m a te ria l

However, th e r e s u l t s i n d i c a t e no

d i f f e r e n c e i n a v a i l a b l e iv a te r betw een th e two a r e a s d u r in g th e

c r i t ic e d p e r i o d o f g ro w th ( J u l y , A u g u s t) .

L ig h t I n t e n s i t y
At v a r i o u s i n t e r v a l s th ro u g h o u t t h e grow ing s e a s o n , l i g h t i n t e n s i t y
m easurem ents were ta k e n in b o th Area. X and A rea Y.

These r e a d i n g s were

r e c o r d e d w ith a p h o t o e l e c t r i c c e l l u t i l i z i n g th e i n t e n s i t y o f r e f l e c t e d
l i g h t e x p r e s s e d in term s o f a p e r c e n t of f u l l s u n lig h t#
of th e l i g h t in t e n s i t y

S in c e no r e c o r d

made a t any tim e p r i o r to th e p r e s e n t r e a d i n g s ,

th e n u m e r ic a l r e s u l t s a r e n o t in c lu d e d h e r e .

Howre v e r , th e r e s u l t s o f th e

p r e s e n t s t u d y r e v e a l t h a t t h e a v e ra g e l i g h t i n t e n s i t i e s in A rea Y a r e
c o n s i d e r a b l y g r e a t e r th a n in A rea X.

T his r e s u l t was a n t i c i p a t e d due to

t h e more shad ed end l e s s exposed s i t e c o n d i t i o n s o f A rea X.
W ith t h e l i m i t e d d a t a a v a i l a b l e i t i s d i f f i c u l t to d e te r m in e what
e f f e c t l i g h t i n t e n s i t y p la y s in t h e r o l e o f a s e p a r a t e c l i m a t i c f a c t o r .
F u r th e r m o r e , i t i s d i f f i c u l t to e x p re s s q u a n t i t a t i v e l y which p o r t i o n o f
th e s o l a r r a d i a t i o n e x i s t s as l i g h t i n t e n s i t y ,
S in c e no

l i g h t q u a lity , or as h e a t.

l i g h t r e a d i n g s have b een ta k e n d u r in g t h e 1 5 -y e a r i n t e r v a l

p r e v i o u s to t h e e s t a b l i s h m e n t o f t h i s p l a n t a t i o n , i t i s v i r t u a l l y im p o s s ib le
t o e s t a b l i s h any c o n c r e t e e v id e n c e as to t h e d i r e c t e f f e c t o f l i g h t upon
h e i g h t g ro w th , w ith t h e e x c e p tio n o f th e e x t e r n a l e v id e n c e o f s u n s c a l d .
The r o l e o f l i g h t in b o th a r e a s i n t h i s s t u d y is t h e r e f o r e b a se d upon th e
i n d i r e c t o b s e r v a t i o n a l r e s u l t s of s o l a r r a d i a t i o n r a t h e r th a n a c a u s e of
h e ig h t d if f e r e n tia tio n #

210

C e rta in an atom ical fe a tu r e s o f t u lip tr e e s in Area X su g g e st a
resp o n se to low er l i g h t in t e n s it i e s *

Such fe a tu r e s as n a tu r a l pruning

o f th e low er branches in t h is a rea in d ic a te th e e f f e c t o f the p resen ce
o f th e o ld growth hardwood and th e g r e a te r h e ig h t growth o f th e s e t r e e s .
G ross o b s e r v a tio n on the th ic k n e ss o f l e a v e s , l e a f c o lo r , and g e n e r a l
l e a f su c c u le n c e does not r e v e a l any marked d if fe r e n c e in the two h a b it a t s .
At th e tim e o f e sta b lish m e n t o f t h is p la n ta tio n and fo r many y e a rs fo llo w ­
ing t h i s i n i t i a l grow th, i t i s presumed th a t a l l tr e e s in th e p la n ta tio n
were r e c e iv in g app roxim ately th e same l i g h t in t e n s it y , and th a t d i f f e r ­
e n t ia t io n in h e ig h t grow th ba,sed upon l i g h t c o n d itio n s per se i s not
te n a b le .
Thus, w ith th e lim it e d d ata a v a ila b le , i t appears th at l i g h t is
com p lexly a s s o c ia t e d w ith th e oth er in te g r a te d s i t e f a c to r s in t h i s
stu d y .

Por exam ple, in Area Y, the g r e a te r l i g h t in t e n s it y

is a s s o c ia te d

w ith th e d r ie r h a b ita t and h igh er tr a n s p ir a tio n r a te s as shown by
su p p lem en tal e v id e n c e .

Most o f th e ev id en ce in t h is t h e s is p o in ts to

th e f a c t th a t l i g h t i s in te g r a te d w ith th e oth er s i t e fa c to r s but i s
b ein g masked by o th e r more lim it in g fa c to r s w ith r e fe r e n c e to th e h e ig h t
grow th d i f f e r e n t i a l .
D is c u ss io n o f R e su lts
A grow ing season stud y o f seven m ic r o clim a tic fa c to r s in Area X and
Area Y shows in v i r t u a l l y every c a se th a t th ese in te g r a te d f a c t o r s ,
supplem ented by edaphic and b io l o g ic a l f a c t o r s , are a s s o c ia te d w ith a
marked d i f f e r e n t i a l h e ig h t growth fo r plan ta t ion-grown t u lip p o p la r .
A ll o f th e s e m ic r o c lim a tic f a c t o r s in d ic a te th a t the m oisture regim en,

211

e i t h e r d i r e c t l y or in d i r e c t l y , i s most l i k e l y th e major fu n c tio n r e s u lt in g
in th e d i f f e r e n t i a l h e ig h t growth o f th e exp erim en tal p la n ta tio n *

The

p r e se n c e o f an o ld —g ro v th hardv/ood sta n d a d ja c e n t to Area X has a lte r e d
th e m ic r o clim a te in t h is area and, r e v e a ls ra th e r c le a r ly some o f the
s i l v i c a l fe a tu r e s to "be co n sid ered in g ro v in g p la n ta tio n t u lip p o p la r .
The m icro c l im a tic fe a tu r e s o f Area X and Area Y have p r e v io u s ly "been
v a l i d a t e d s t a t i s t i c a l l y w ith r e fe r e n c e to p r e c ip it a t io n and tem p eratu re.

212

SOIL MICROBIOLOGICAL EXPERIMENTS ( QUANTITATIVE)
The R e l a t i o n Between Numbers o f S o i l Organisms and t h e Edaphic
and M ic r o c l i m a t i c F a c t o r s o f A rea X and A rea Y
F i e l d E x p e rim e n ta l Method:
D u rin g t h e grow ing s e a s o n o f 1951* s o i l sam ples f o r m i c r o b i o l o g i c a l
s t u d i e s were ta k e n from A rea X and A rea Y.

These sam ples were c o l l e c t e d

and p r e s e r v e d by a method o r i g i n a t e d by th e p r e s e n t i n v e s t i g a t o r .

At

a p p r o p r i a t e i n t e r v a l s th ro u g h o u t th e growing sea so n th e s o i l s were
sam pled f o r numbers o f f u n g i , b a c t e r i a , and a c tin o m y c e te s e x i s t i n g i n
f o u r s e p a r a t e s o i l h o r iz o n s i n each e x p e r im e n ta l a r e a ( F ig u r e s 50“ 53)*
A r e v i s e d method o f c o l l e c t i n g m i c r o b i a l s o i l samples was c a r r i e d o u t as
fo llo w s:
1.

G la ss c o n t a i n e r s of 65 m i l l i l i t e r c a p a c i t y were s t e r i l i z e d
in an

oven a t 105° C f o r a p e r i o d o f one h o u r.

S te rile lid s

were th e n screw ed t i g h t l y to t h e empty g l a s s c o n t a i n e r s and
ta k e n d i r e c t l y i n t o th e f i e l d .
2.

By means o f a p o s t - h o l e d i g g e r , s o i l p r o f i l e s were exposed
to an

a p p ro p ria te d e ath .

U sing an o r d i n a r y s t e r i l e , wooden

ic e - c r e a m spoon, enough s o i l was ta k en a t d e f i n i t e s o i l
h o r iz o n d e p th s to f i l l each c o n t a i n e r .

A f t e r each i n d i v i d u a l

s o i l s a m p lin g , th e wooden snoon was d i s c a r d e d .

T h is method

e l i m i n a t e s th e u s u a l t e d i o u s and cumbersome p ro c e d u re o f
i g n i t i n g a l c o h o l on a tro w e l p r i o r to e a c h sam p ling in o r d e r
to p r e v e n t c o n ta m in a tio n .

213

3 * A fte r th e sam ples were taken a t each n a tu r a l s o i l h o rizo n ,

a beaker o f p a r a ff in wax was m elted and the sample c o n ta in er s
em ersed, thus s e a lin g them from a ir and co n ta m in a tio n .

T his

w a x -s e a lin g p r o c e ss en a b les th e in v e s tig a to r to keep the
sam ples i n d e f i n i t e l y u n t il th e s o i l s are ready to be sampled
fo r m icro b es.

In a d d itio n , the s o i l s can be run a t th e same

pH and m o istu re co n ten t as o r ig i n a lly sam pled.
The m ic r o b ia l s o i l samples were taken a t app roxim ately th e same area
l o c a t io n as th e m ic r o cl imat ic d a ta .

U niform ity in th e c o r r e la t io n o f

edaphic and c lim a t ic d ata w ith th e m ic r o b io lo g ic a l changes was thus
o b ta in e d .
la b o r a to r y E xperim ental Method:
The la b o r a to r y procedure u sed in i s o la t i n g th e d e sir e d organism s from
each s o i l sample d iv id e s i t s e l f in to two p a r ts:
1.

From th e s o i l sam ples taken a t S ta tio n s I and I I , a com posite
sample was made to r ep r e se n t each horizon in Area X;
s im ila r ly , com posite samples were made fo r each h orizon in
Area Y.
S o il d ilu t io n s o f each com posite s o i l were
f o llo w s :

prepared as

The a d d itio n o f 10 grams o f s o i l to 1000 c c . o f

s t e r i l e d i s t i l l e d water g iv in g a d ilu t io n o f 1 :1 0 0 .

A fte r

the c o a rse p a r t ic le s had s e t t l e d out a f t e r sh a k in g , 10 cc*
o f th e 1:100 d ilu t io n was p ip e t te d in to 90 c c . o f s t e r i l e
d i s t i l l e d w ater.

S u c c e ss iv e tr a n s fe r s were made r e s u lt in g in

a s e r i e s o f d il u t io n s .
and 1 :1 ,0 0 0 ,0 0 0 .

These were 1 :1 0 0 ,

1 :1 0 0 0 ,

A ll work was done a s e p t i c a l l y .

1 :1 0 ,0 0 0 ,

2lk

2.

S e le c t io n o f media and c u ltu r in g procedure fo r "bacteria,
a c tin o m y ce te s and fu n g i:
From th e above d i l u t i o n s , 1 c c . o f each was d isp en sed by
s t e r i l e p ip e t t e s in to a s e l e c t i v e m edia and poured a s e p t ic a ll y
in to s t e r i l e p e t r i d is h e s .

T his m ixture o f agar* and s o i l

d il u t io n was allow ed to harden and th e c u ltu r e s were p la c e d in
a c u ltu r e room at 28° 0 .

The b a c te r ia and a ctin o m y cetes were

p e r m itted to grow one week or l e s s b e fo r e observa/tions were
made and th e fu n g i were a llo w ed fo u r days b e fo r e o b se r v in g .
The medium used f o r b a c te r ia was N utrose agar; f o r fu n g i;
a P e p to n e -g lu c o se a c id agar used w ith a pH between
so th a t b a c t e r ia would not d e v e lo p .

and 4*0

The media used were as

fo llo w s :
B a c te r ia and A ctinom ycetes - U utrose agar
Agar
Hutrose
G lucose

12 .5 grams
2.0
1 .0

K2HP0i^

0 .2

MgSO^.7H20
FeS0i |. 7H20
Tap Water
R e a c tio n pH

0 .2
tra c e
1 .0 l i t e r
6.3 (no a d ju s tm e n t)

Fungi

-

Peptone g lu c o se a cid agar

Agar
KH^PO^
MgS01+.7H20
Peptone
G lucose
D i s t i l l e d Water
R e a c tio n pH

25.O grams
1 .0
0 .5
5*0
1 0 .0
1 .0 l i t e r
3*# t0 ^*0 ( a d j u s t e d )

In a l l c a se s where in o c u la tio n s were made, g la ssw a re was th orou ghly
s t e r i l i s e d and the media used were autocla.ved p r io r to each s o i l 11run11 in

215

o r d e r to p r e v e n t c o n t a m i n a t i o n .

jHach d i l u t i o n was ru n i n d u p l i c a t e b o th

f o r b a c t e r i a and f u n g i , in a d d i t i o n to c o n t r o l s *

The number o f o rganism s

computed from t h e p l a t e s r e p r e s e n t th e a v e r a g e v a lu e s o f t h r e e d i l u t i o n s ,
o r t h e a v e r a g e v a l u e of s i x i n d i v i d u a l p l a t e s f o r e ach s o i l h o r i z o n .
M o is tu r e c o n t e n t s w ere o b t a i n e d f o r e ach h o r iz o n im m e d ia te ly b e f o r e th e
i s o l a t i o n s were made*

T h is was done by h e a t i n g t h e com posite sam ples

a t 90° C u n t i l a l l vrater was l o s t ; t h e p e r c e n ta g e f i g u r e s o b t a i n e d were
i n d i c a t i v e o f t h e amount o f w a te r l o s t in each sam ple, and th e number o f
o rg a n is m s p r e s e n t p e r gram d ry w e ig h t o f s o i l was computed from t h e s e
r e s u l t s , u s in g t h e p l a t e method f o r c o u n tin g m ic ro b e s .

F o r e ac h s o i l

h o r i z o n , th e a c i d i t y (pH) was o b t a i n e d by th e g l a s s - e l e c t r o d e pH m e te r .
S e v e r a l exem plary p h o to g ra p h s o f t h e p l a t e c o u n t were made in o r d e r
to i l l u s t r a t e t h e p r i n c i p l e s in v o lv e d ( F ig u r e s 5 ^ 5 ^ ) *

The number o f

o rg a n ism s on e ach p l a t e was c o u n te d by means o f a m icro sco pe and c o u n tin g
p la te .

Only t h e 1 :1 00 and 1:1000 d i l u t i o n s were u s e d f o r s t a t i s t i c a l

p r e s e n t a t i o n o f numbers o f o rg a n ism s a p p e a rin g on th e p l a t e s .

A fte r

c o r r e c t i o n f o r m o is tu r e c o n t e n t , th e numbers o f org an ism s were p l o t t e d i n
o r d e r t o compare q u a n t i t a t i v e l y t h e d i f f e r e n c e i n m ic ro b ia l c o u n ts betw een
A re a X and A rea Y.
O b je c ti v e s
The p r e s e n t m i c r o b i o l o g i c a l i n v e s t i g a t i o n s were co n ce rn e d w ith tile
s o i l a s a mass o f l i v i n g d e b r i s ,
f u n g i , a l g a e and p r o t o z o a .
o f th e s o i l f l o r a and f a u n a .

in c lu d in g c e r t a i n b a c t e r i a , a c ti n o m y c e te s ,

These l i v i n g m icrobes a r e n o t a co m p lete l i s t
However, th e b a c t e r i a , f u n g i and a c tin o m y c e te s

e x e r t a p ro f o u n d i n f l u e n c e upon t h e g e n e t i c a l developm ent o f s o i l p r o f i l e s
as w e ll as an i n d i r e c t e f f e c t uuon f o r e s t t r e e s .

T his s tu d y i s s t r i c t l y

216

q u a n t i t a t i v e in i t s approach..

I n most s o i l s t h e q u a l i t a t i v e d i s t r i b u t i o n

of o rg a n ism s re m a in s much t h e same, b u t t h e r e a r e v e r y marked d i f f e r e n c e s
in th e q u a n t i t a t i v e r e l a t i o n s h i p s .

B i o l o g i c a l t r a n s f o r m a t i o n s b ro u g h t

a b o u t by s o i l o rg a n ism s a r e e x tre m e ly complex, and i t i s assumed t h a t t h e
f o r e s t e r p o s s e s s e s a g e n e r a l background i n th e i m p l i c a t i o n s o f t h i s s t u d y .
No a t t e m p t h a s b e en made t o e n a b le th e r e a d e r t o a n a ly z e th e r e s u l t s of
t h e s e e x p e r im e n ts by means o f a s t r i c t ind ex t h a t w i l l h o ld t r u e in a l l
cases.

N e v e r t h e l e s s , t h e r e s u l t s a r e a f u n c t i o n of two in d e p en d e n t

b o d i e s , th e s o i l and th e f o r e s t , e ach o f w hich a r e a c t e d upon by c l i m a t i c
i n f l u e n c e s , a l l o f which a r e i n t e g r a t e d p a r t s o f th e same dynamic system
i n f l u e n c i n g th e g ro w th o f t u l i p p o p l a r .

I n a l l c o m p a ra tiv e s t u d i e s

c e r t a i n v a r i a b l e s and i n c i d e n t a l f a c t o r s e n t e r in ; no d i r e c t o r i n d i r e c t
c o r r e l a t i o n betw een t h e s o i l and th e grow th o f th e f o r e s t s ta n d s d e s c r i b e d
can be e x p e c te d to h o ld t r u e in a l l s i t u a t i o n s .

Since no i d e n t i c a l s t u d i e s

l i k e t h e one p r e s e n t e d h e re have been made, i n t e r p r e t a t i o n o f d a t a i s
o n ly i n d i c a t i v e o f p r i n c i p l e s and t r e n d s s u p p le m e n ta l t o o t h e r f a c t o r s .
P r a c t i c a l l y no s i l v i c a l s t u d i e s have s p e c i f i c a l l y shown t h e r e l a t i o n s h i p
o f o rg a n is m s to a s e t o f i n t e g r a t e d s i t e f a c t o r s th ro u g h t a growing s e a s o n .
T h is p o r t i o n o f th e d i s s e r t a t i o n has th e f o llo w in g s p e c i f i c o b j e c t i v e s :
1.

To p r e s e n t q u a n t i t a t i v e d a t a c o n c e rn in g b a c t e r i a , f u n g i , and
a c ti n o m y c e te s in two c o n t r a s t i n g s i t e s o f th e same age and
d e n sity .

These two s i t e s r e p r e s e n t an a r e a o f good h e i g h t

g ro w th and an a r e a o f po or h e i g h t grow th o f p la n t a t i o n - g r o w n
t u lip p o p la r.
2.

To show t h e f l u c t u a t i o n in th e p o p u l a t i o n of o rg a n ism s th r o u g h o u t
th e gro w in g sea.son

on compared t u l i p p o p l a r s i t e s , by u t i ­

l i s i n g s o i l h o riz o n s a s th e d i f f e r e n t i a t i n g c r i t e r i o n .

217

3*

To c o r r e l a t e t h e f l u c t u a t i o n in p o p u l a t i o n o f org an ism s
t h r o u g h o u t t h e growing s e a s o n w ith th e f o l l o w i n g m ajor
m i c r o c l i m a t i c and e d a p h ic f a c t o r s in each a r e a :
(1)

s o i l - s u r f a c e te m p e r a tu r e

( 2)

m o istu re c o n te n t o f

(3)

ra te

(H)

so il

o r g a n ic m a t t e r

(5)

so il

a c i d i t y (pH)

s o i l to a d e p th o f s i x in c h e s

o f e v a p o r a t i o n and a i r te m p e r a tu r e

I n i n t e r p r e t i n g t h e r e s u l t s o f a q u a n t i t a t i v e m i c r o b i a l s tu d y i t s h o u ld
be c o n s t a n t l y k e p t in mind t h a t th e numbers o f organism s r e f e r r e d to a r e
o n ly r e l a t i v e f i g u r e s *

They sh o u ld n o t be i n t e r p r e t e d as r e p r e s e n t i n g a,

c o n s t a n t number o f o rg a n ism s in a p a r t i c u l a r s o i l ; th e c o u n ts r e f e r o n ly
to t h e r e l a t i v e abundance o f c e r t a i n ty p e s o f m ic r o b ia l c e l l s a t th e t i n e
t h a t t h e d e t e r m i n a t i o n was made.
m e n ta l c o n d i t i o n s a r e m o d if ie d .

G re a t changes o c cu r when c e r t a i n e n v ir o n ­
The manner i n which t h e s e organ ism s v a ry

w i t h a s e t o f i n t e g r a t e d s i t e f a c t o r s th ro u g h o u t an e n t i r e grow ing se a so n
in two c o n t r a s t i n g t u l i p p o p l a r h a b i t a t s is th e o b j e c t i v e o f t h i s m ic ro ­
b io lo g ic a l stu d y .

In e s s e n c e , th e f i n d i n g s o f t h i s b i o l o g i c a l i n v e s t i g a t i o n

m e re ly a tte m p t to c o r r o b o r a t e and v a l i d a t e t h e m i c r o e l i m a t i c and ed ap h ic
stu d ie s.

The r o l e o f m ic ro o rg a n ism s a s to t h e i r f u n c t i o n , a c t i v i t i e s , and

t r a n s f o r m a t i o n s a r e n o t in c lu d e d h e r e .

This i n v e s t i g a t i o n i s d e s ig n e d to

d e m o n s t r a t e how m i c r o b i a l s t u d i e s can be in c o r p o r a te d i n t o t h e f o r e s t e r ' s
c o n c e p t o f s i t e q u a l i t y by i n t e g r a t i n g t h e s o i l f l o r a w ith o t h e r s i t e
fa c to rs.

S in c e th e s u r f a c e s o i l h o r iz o n s r e f l e c t th e e x t e r n a l e f f e c t s o f

t h e im m ediate e n v iro n m e n t, th e q u a n t i t a t i v e c o r r e l a t i o n o f o rg a n ism s to
s o i l and c l i m a t e i s i n t e r p r e t e d a n d p l o t t e d by s o i l h o r i z o n s , AQ and A^.

218

Pig. 50.

VERTICAL DISTRIBUTION OP SOIL MICROBES IN AREA X
AND AREA Y DURING THE SPRING

Area Area
X
Y

2 .0

30

1.5

120

Nuniberfl of organisms per gram
dry weight o f s o il

-

-

a

80

h 1 *0

*ri

ss
m
5
u

I
<D

’5

20

. 25-

JL

A0 A-l
Pungi

A2 B2

‘o “A^1 A2
A c tin o m y c e s

Kfj ?*■; Zi,'Z\

b2

111
Ao A1 a 2
Bacteria

219

P is* 5 1 .

VERTICAL DISTRIBUTION OF SOIL MICROBES IH AREA X
AND AREA Y DURING EARLY SUMMER

3.0

Area
X

Area
Y

2.5

2.0

120

30

1 .5 -

Numbers of organisms per gram
dry weight of s o il

CO

'S
CO

t«a 20
CO

g

II
i
CO
©
•**

80

to
a
o

•H 1 * 0

©

cJ

o

©

« rl

10

4-3
O
•*!

.5 20

0

.25

Jl

111
Ao A1 A2
Ftmgi

B2

Ao

A1

A2

A c tin o m y c e s

i fior* ?. on

B2

A.

Ao

B acteria

B<

220

Fig. 52

VERTICAL DISTRIBUTION OP SOIL MICROBES IN AREA X
AND AREA Y DURING MID-SUMMER

Area
X

Area
Y

2 .5

2.0

Numbers of organisms per gram
dry w e ig h t of s o il
120

30

1 .5

01

80

n 20
ca

g

•H

as

<D
43
0
P

10

O
Pi
«H
O

40

20

43
fH
0
43
8

.5 . 25-

1

h

Ao A1 a 2
Fungi

B2

A0 Ax A2
Actinomyces

B.

Ao

A1

a2

B acteria

b:

221

F ig .

53.

VERTICAL DISTRIBUTION OF SOIL MICROBES IN AREA X
AND AREA T DURING EARLY AUTUMN

Area Area
X

Y

2 .5

Numbers of organisms per gram
d ry weight of s o i l

2.0

120

30

1 .5

CO
15
01

g
01

20

m
Q)

80

t

-

«H
s

©

10

o 1 .0

kO

20

U
<D
O .5

■P

.25 -

Ao

A1

Fungi

A1 A2 B2

A2 B2

A c tin o m y c e s

!',0 !

on

Ao A1 A2 B2
B acteria

222

R esu lts
T o t a l Abundance o f O rganisms!
The r e l a t i v e numbers o f a l l t h r e e c l a s s e s o f organism s i n v e s t i g a t e d
i n A re a X and Area, Y ra n g e d from a minimum o f 1000 f u n g i p e r gram to a
maximum o f 3*i00»0G0 " b a c te r ia p e r gram th ro u g h o u t t h e c o u rs e o f th e growing
season.

Of th e t h r e e c l a s s e s o f o rg a n is m s, t h e b a c t e r i a were fo u n d in

g r e a t e s t numbers f o ll o w e d by th e a c tin o m y c e te s snd f u n g i ( F ig u r e s 50“ 5 3 ) *
A lth o u g h t h e numbers o f o rganism s f l u c t u a t e d w ith t h e s e a s o n , th e g r e a t e s t
t o t a l numbers o f b a c t e r i a and f u n g i o c c u r r e d in A rea Y th ro u g h o u t th e
g ro w in g s e a s o n .
th a n A re a Y.

A rea X e x h i b i t e d g r e a t e r t o t a l p o p u l a t i o n s o f a n tin o m y c e te s

The g r e a t e s t d i f f e r e n c e s in numbers o f organism s betw een

A re a X and A re a Y o c c u r r e d w ith th e b a c t e r i a ; d i f f e r e n c e s f o r th e f u n g i
end a c ti n o m y c e te s w ere n o t extreme w i t h th e e x c e p tio n o f th e

c.

h o rizo n .

The s e a s o n a l change i n numbers o f o rg anism s showed a maximum c o u n t i n
s p r i n g , a minimum d u r in g mid-summer, and a sec o n d a ry maximum i n e a .rly
autum n.

T h is c y c l i c f l u c t u a t i o n th ro u g h o u t th e growing s e a s o n o c c u r r e d

w i t h a l l t h r e e c l a s s e s o f o rg a n ism s s t u d i e d .

The g r e a t e s t numbers o f

f u n g i , as d e te r m in e d by p l a t e c o u n t, were found i n th e B2 h o r iz o n f o r b o th
A re a X and Y f o r a l l p e r i o d s o f th e g ro w in g s e a s o n .

I n c o n t r a s t to th e

fu ng ad p o p u l a t i o n , th e b a c t e r i a l numbers were g r e a t e s t in th e AQ and Aj_
h o r i z o n s th r o u g h o u t t h e s e a s o n .
B2 h o r i z o n f o r A rea X.

A ctinom ycete numbers were h i g h e s t in th e

The t o t a l abundance of o rgan ism s i n b o th a r e a s

was n o t h ig h in r e l a t i o n to numbers o f organism s fo u n d in s i m i l a r s o i l
ty p e s

v a r ioue i n v e s t i g a t o r s .

The h i g h e s t i n d i v i d u a l b a c t e r i a l c o u n t

f o r any one h o r iz o n o c c u r r e d in A rea Y a t th e

h o r iz o n .

223

A pp ro ach to I n t e r p r e t a t i o n of R e s u l t s :
F u n g i:

The r e s u l t s p r e s e n t e d a r e p r i m a r i l y q u a n t i t a t i v e .

F o r each

d i l u t i o n , t h e numbers shown i n F i g u r e s 5^ an& 55 r e p r e s e n t
th e number o f c o lo n ie s in com p osite sam ples th ro u g h o u t
grow ing s e a s o n .

th e

Assuming t h a t e a c h c o lo n y d e v elo p e d from a

s i n g l e sp o re o r hypha, th e number p e r gram can be computed bym u l t i p l y i n g th e number on t h e p l a t e by t h e d i l u t i o n .

A d ju s t­

ment w ith r e f e r e n c e t o m o is tu r e c o n t e n t o f t h e s o i l must be
made so t h a t th e number o f org an ism s p r e s e n t i s b a se d upon
d ry w e ig h t o f t h e s o i l .
B a c t e r i a and A c tin o m y c e te s :

The r e s u l t s a r e e n t i r e l y q u a n t i t a t i v e

s i n c e no e f f o r t was made to i d e n t i f y t h e c o lo n ie s .

A c tin o -

m ycete numbers a r e computed p e r gram b a se d upon d ry w e ig h t o f
th e s o i l th e same way as th e b a c t e r i a l and f u n g a l numbers.
I n t e r p r e t a t i o n o f R e s u lts
I n o r d e r t o show a r e l a t i o n s h i p betw een th e s o i l organism s o f two
c o n tra stin g

t u l i p p o p l a r s i t e s , an o v e r a l l e x p la n a tio n o f th e r o l e

f u n g i , b a c t e r i a , an d a c tin o m y c e te s
n ecessary .

of

in r e f e r e n c e to what th e y do i s

A r e l a t i o n s h i p e x i s t s between th e s o i l and f o r e s t g row th and

i s q u i t e v a r i a b l e and complex.

The p a r t t h a t each group of organism s

p l a y s in t h i s s tu d y i s p r e s e n t e d , f o l l o w i n g a b r i e f d e s c r i p t i o n o f t h e i r
ro le in g e n eral.
Number o f F u n g i in F o r e s t S o i l s :
F u n g i a r e f r e e o f c h l o r o p h y l l and d e r i v e t h e i r en erg y from th e
d e c o m p o s itio n o f dead o r l i v i n g m a t t e r , o rg a n ic in c h a r a c t e r .

T h e ir

22k

p r e v a l e n c e i n t h e s o i l i s c l o s e l y t i e d up v /ith t h e p r e s e n c e o r a b se n c e o f
decom posing o r g a n ic m a t t e r .

They o c c u r in s o i l s e i t h e r a s f r e e molds o r

as s y m b io tic f u n g i fo rm in g m y c o rrh iz a e v ;ith th e r o o t s o f h i g h e r p l a n t s as
shown b y Wilde (19^-6).

The forms v?ith which t h e p r e s e n t s tu d y i s co n ce rn e d

a r e t h e o r d i n a r y f i l a m e n t o u s f u n g i (P h yco m y cetes, Ascomycetes and th e F u ng i
I m p e r f e c t i ) w hich o c c u r a,s f r e e m old s.

F u n g i g e n e r a l l y o c c u r a b u n d a n tly

in t h e s o i l , p a r t i c u l a r l y in s o i l s o f h ig h o r g a n ic c o n te n t where th e
a c i d i t y is h i g h .

T his means t h a t t h e f u n g i can w ith s ta n d g r e a t e r a c i d i t i e s

th a n t h e b a c t e r i a and a c ti n o m y c e te s .

Humbers of f u n g i w i l l i n c r e a s e w ith

m o i s t u r e c o n t e n t p r o v i d e d t h e r e i s good a e r a t i o n , and a s u p p ly of o r g a n ic
m a t t e r w i t h t h e p r o p e r s o i l r e a c t i o n as p o i n t e d o u t by Waksman ( 19 2 7 ) .
The g r e a t e s t numbers o f f u n g i a r e fo u n d in th e upp er few in c h e s o f s o i l
b u t w i l l o c c u r to a d e p t h o f a t l e a s t f o u r o r f i v e f e e t .

I t i s e v id e n t

t h a t th e r o l e o f f u n g i in f o r e s t s o i l s cann ot be o v e r-e m p h a siz e d , as th e y
decompose p r o t e i n s , c e l l u l o s e , h e m i c e l l u l o s e , and most o t h e r c a r b o h y d r a t e s .
The c o m p o s itio n o f t h e fu ng us f l o r a o f th e s o i l changes with, a c o r re s p o n d in g
change in t h e n a t u r e o f th e s o i l .

I t Is im p o r ta n t to n o te t h a t n u m e r i c a l l y ,

as d e te r m in e d by t h e number o f s i n g l e c e l l s , th e f u n g i a r e few er in th e
s o i l th a n t h e b a c t e r i a a lth o u g h t h e i r a c t u a l abundance, as m easured by
th e amount o f c e l l s u b s ta n c e p ro d u c e d , may be c o n s id e r a b ly g r e a t e r th a n
t h a t o f b a c t e r i a l g ro w th .

This r e s i d u e o f m y c e lia adds to t h e n i tr o g e n o u s

c o n t e n t o f th e s o i l complex.

As a r u l e , most f u n g i grow under a e r o b ic

c o n d i t i o n s where most o f th e c e l l s u b s ta n c e is p ro d u c e d .
S ign ifican t

1.

R e s u l t s on F u n g i; ( P e f e r to g r a p h s , p h o to g ra p h s , and n u m e ric a l
da t a)
The t o t a l r e l a t i v e numbers of' f u n g i o c c u r r in g in b o th p l a n t a ­
t i o n s i t e s , A rea X end A rea T, were m arkedly s i m i l a r f o r an

225

e n t i r e grow ing s e a s o n in th e f o u r s o i l h o r iz o n s i n v e s t i g a t e d .
T h is l a c k o f a s i g n i f i c a n t d i f f e r e n c e c a n he se e n by r e f e r e n c e
to F i g u r e s 5 ^ and 5 5 , and i n T a b le s 52 and 5 3 .
2.

A s l i g h t l y g r e a t e r t o t a l number o f f u n g i o c c u r r e d i n A rea T
f o r t h e t o t a l s o i l p r o f i l e th ro u g h o u t t h e groining s e a s o n .

3-

F u n g i o c c u r r e d i n l e a s t t o t a l numbers o f o rg a n ism s t h a n any
o f t h e t h r e e g rou ps o f org an ism s s t u d i e d .

T h is was t r u e f o r

b o t h A re a X and A rea Y.
The g r e a t e s t number o f f u n g i p e r gram o f s o i l f o r b o t h a r e a s
o c c u r r e d in th e Bg h o r i z o n , where th e number o f c o lo n ie s r i s e s
to 1 6 ,7 0 0 p e r gram b a se d on d ry w e ig ht of th e s o i l .
5.

In b o t h a r e a s , t h e f u n g a l p o p u l a t i o n in th e AQ and A^ h o r iz o n s
was h i g h e s t in th e s p r i n g , dropped to a minimum i n mid-summer,
and r e a c h e d a sec o n d a ry maximum in e a r l y autumn.

C o n c lu sio n s R eg ard in g Fungus R e s u l t s :
S in c e t h e r e i s no u s e f u l method y e t d e v is e d to d e te rm in e how much o f
t h e fu n g u s m a t e r i a l e x i s t s in t h e s o i l a s mycelium o r as s p o r e s by t h i s
i s o l a t i o n method, t h e r e i s no c o n c r e te way of d e te r m in in g what p e r c e n ta g e
o f th e c o l o n i e s i s due to s p o re s and what p e r c e n ta g e i s due t o p i e c e s o f
m y celia.

W ith t h i s l i m i t a t i o n in mind, th e f a c t rem ains t h a t th e g r e a t e s t

number o f f u n g i ( s p o r e s and m y c e lia ) were found a t th e B2 h o r iz o n in b o th
o la n ta tio n s ite s .

Thus, no d i r e c t c o r r e l a t i o n betw een t h e s e numbers and

th e p o t e n t i a l a c t i v i t y o f t h i s h o r iz o n can be made, u n le s s i t can be
d e te r m in e d what p e r c e n t a g e o f th e s e c o l o n i e s a re s p o re s and mycelium
re sp e c tiv e ly .

S in c e t h e t o t a l number of f u n g i i s g r e a t e s t a t th e

h o r i z o n in b o th a r e a s i t i s p o s s i b l e to i n t e r p r e t t h i s r e s u l t in term s o f

226

F i g . 5 U.
A p h o to g ra p h o f th e r e l a t i v e numbers o f f u n g a l c o lo n ie s
o c c u r r i n g by s o i l h o r iz o n in th e a r e a o f good h e i g h t grow th. The
number o f c o l o n i e s on each p l a t e r e p r e s e n t s s o i l samples e x t r a c t e d
in th e S p r in g (May 20, 1951)• Note th e d im in u tio n in number o f
c o l o n i e s w ith t h e i n c r e a s e d d e p th o f t h e h o riz o n u n t i l th e Bg
h o r i z o n i s r e a c h e d . The l a r g e r number o f c o l o n i e s o c c u r r in g in th e
l a t t e r h o r iz o n i s a f u n c t i o n o f d e c r e a s e in pH a t a s o i l d e p th o f
20 i n c h e s . A l l o f th e d i l u t i o n s show th e same r e l a t i o n s h i p w ith
r e f e r e n c e to th e number o f c o l o n i e s .

227

f a c t o r s w hich l i m i t t h e v e r t i c a l d i s t r i b u t i o n o f f u n g i .

The r e s u l t s o f

T a b le s 52 and 53 r e v e a l s in "both a r e a s t h a t t h e most a l k a l i n e c o n d i t i o n s
o c c u r a t th e s u r f a c e , and a l s o t h e g r e a t e s t c o n t e n t o f o r g a n i c m a t t e r ,
h i g h e s t m o i s t u r e c o n t e n t , g r e a t e r n i t r o g e n c o n te n t and p o r o s i t y o c c u r a t
th e same h o r i z o n .
lo w e r h o r i z o n .

However, t h e g r e a t e s t f u n g a l p o p u l a t i o n o c c u rs a t t h e

T h is r e s u l t r e v e a l s r a t h e r c l e a r l y t h a t th e f u n g a l

p o p u l a t i o n i n t h i s p l a n t a t i o n i s a f u n c t i o n o f th e a c i d i t y o r pH o f th e
h o riz o n concerned.

The more a c i d c o n d i t i o n s a t lo w e r d e p th s i s a p p a r e n t l y

m asking t h e e f f e c t o f o t h e r f a c t o r s *

This c o n c lu s io n r e g a r d in g th e f u n g i

p o i n t s o u t b i o l o g i c a l l y t h a t th e s o i l s a r e s t r o n g l y a c i d and a l s o d i s c l o s e s
t h e 11im m a t u r i t y 11 o f t h e f o r e s t i n s o f a r a s o r g a n i c d e c o m p o s itio n i s con­
cerned.

A ls o , t h e s l i g h t l y h i g h e r t o t a l c o n c e n t r a t i o n o f f u n g i i n A re a Y

s u g g e s t s t h a t t h e s o i l s in t h i s a r e a a re
l e v e l i n s o f a r a s s o i l ty p e i s in v o lv e d .

a t a g e n e ra lly h ig h er f e r t i l i t y
These f a c t s tend to c o r r o b o r a t e

th e e v id e n c e t h a t t h e s o i l m o is tu r e regim en i s masking th e e f f e c t s o f
s o i l t e x t u r e as d e te r m in e d m i c r o b i o l o g i c a l l y .

Thus, th e po or h e i g h t grow th

o f t u l i p p o p l a r in A rea Y c an n o t be e x p la in e d on th e b a s i s o f low s o i l
b i o l o g i c a l c o u n t s , s i n c e j u s t th e r e v e r s e s i t u a t i o n is i n d i c a t e d by t h e s e
re s u lts .
The r e f l e c t i o n o f m ic r o c lim a te upon th e s e a s o n a l f l u c t u a t i o n o f
f u n g i in th e s u r f a c e h o r iz o n s o f b o th a re a s was n o t so marked a s w ith
th e b a c t e r i a l p o p u l a t i o n .

However, t h e low er c o u n ts f o r f u n g i in mid—

onmirip.T* f o r A rea Y a t t h e s u r f a c e h o r iz o n were d e f i n i t e l y a s s o c i a t e d w ith
th e h i g h e r e v a p o r a t i o n r s .t e , l e s s a v a i l a b l e s o i l m oist'.ire, h ig h e r a i r
t e m p e r a t u r e , g r e a t e r l i g h t i n t e n s i t y , and h ig h e r s u r f a c e s o i l te m p e ra tu re s
of th is h a b ita t.

The f a i l u r e o f th e f u n g a l c o u n ts to c o r r e l a t e d i r e c t l y

228

Fig. 55*
A p h o to g r a p h o f th e r e l a t i v e numbers of f u n g a l c o l o n i e s
o c c u r r i n g b y s o i l h o r iz o n i n th e ares, of p o o r h e i g h t grow th.
The number o f c o lo n ie s on each p l a t e d e c r e a s e s w ith d e p th f o r
a l l th e i n d i v i d u a l A h o r i z o n s , and th e n i n c r e a s e s s l i g h t l y
f o r a l l d i l u t i o n s u n t i l th e B2 h o r iz o n is re a c h e d . As w ith
A rea X, th e numbers o f c o l o n i e s in th e Bg h o riz o n i s a
f u n c t i o n o f d e c r e a s e in pH c o n c e n t r a t i o n a t a low er d e p th .
I n c o n t r a s t to F i g . 5^ (A rea X ), t h e r e is a g r e a t e r
number o f c o lo n ie s in A rea Y vrith the e x c e p tio n o f th e 3g
h o r i z o n . A rea Y, as i l l u s t r a t e d m i c r o b i o l o g i c a l l y above, has
s l i g h t l y g r e a t e r c o n t e n t o f o r g a n ic m a t t e r , g r e a t e r p o r o s i t y ,
h i g h e r w a t e r - h o l d i n g c a p a c i t y , g r e a t e r a c i d i t y , and a n a rro w e r
C/N r a t i o th a n A rea X.

229

w i t h th e o r g a n i c m a t t e r c o n te n t o f th e s u r f a c e h o r iz o n s v/as su p p o se d ly due
to t h e im m a tu rity o f th e p l a n t a t i o n ; a p e r i o d o f f i f t e e n y e a r s i s n o t lo n g
w i t h r e s p e c t to th e d e ca y o f r e s i s t a n t t r e e p r o d u c t s d e p o s i t e d on th e
f o r e s t flo o r*

The l e s s e r s e n s i t i v i t y o f f u n g a l p o p u l a t i o n s a t th e s u r f a c e

h o r i z o n s to m i c r o c l i m a t i c f a c t o r s i s s u g g e s te d in t h i s s t u d y , s in c e th e
q u a n t i t a t i v e c o u n ts f l u c t u a t e l e s s r e s p o n s i v e l y th a n th e " b a c te ria and
actin o m y ce te s.

Thus, t h e f l u c t u a t i o n in th e f u n g a l p o p u l a t i o n can be

u t i l i z e d t o su pp lem ent th e e f f e c t o f a c i d i t y (pH) and m ic ro c lim a t ic
e le m e n ts i n s o i l s o f p l a n t a t i o n - g r o w n t u l i p p o p l a r .

These f i n d i n g s a r e

in a c c o r d w i t h th e f o r e s t e r ' s c o n ce p t of s i t e q u a l i t y in r e l a t i o n to
f o r e s t g ro w th .
lu m b e rs o f B a c te r ia , and A ctin o m y cetes i n T o r e s t S o i l s :
B a c t e r i a as a group a r e th e most a b u n d a n t o rg an ism s in th e s o i l .

In

t h e i r a c t i v i t i e s and numbers th e y exceed a l l o t h e r s o i l org an ism s e x c e p t
in th e b u l k o f o r g a n i c c e l l s u b s ta n c e found in t h e s o i l as l i v i n g and dead
m ic r o b e s .

I t i s n o t e x c e p t i o n a l to f i n d h u n d re d s o f m i l l i o n s o f b a c t e r i a l

c e l l s in a gram o f s o i l , p a r t i c u l a r l y where t h e o r g a n ic s u b s t a n c e s a r e
p r e s e n t a c c o r d in g to Tfaksman and St a r k e y (193*)•
I n t h i s s tu d y t h e b a c t e r i a were i s o l a t e d w ith th e a c tin o m y c e te s and
i t i s a p p r o p r i a t e t o p r e s e n t them t o g e t h e r s i n c e m i c r o s c o p i c a l l y th e s p o re s
o f th e a c tin o m y c e te s ap p ea r much l i k e b a c t e r i a l c e l l s .

However, as a g ro u p ,

th e a c tin o m y c e te s may be c o n s id e r e d d i s t i n c t b e ca u se th e y have c h a r a c t e r ­
i s t i c s t h a t re s e m b le b o th f u n g i and b a c t e r i a .

Ho a tte m p t i s made h e r e to

s e a r e a a t e th e a u t o t r o p h i c and h e t e r o t r o p h i c b a c t e r i a as to t h e i r p h y s io lo g y
and m orphology.

Most o f th e b a c t e r i a d e v e lo p in g on th e p l a t e s a r e h e t e r o ­

t r o p h i c f o r m s , r e q u i r i n g combined n i t r o g e n , a lth o u g h s t i l l l a r g e r numbers
may d e v e lo p s lo w ly o r n o t a t a l l .

230

L o h n is (1886) came to t h e c o n c lu s io n t h a t a d e t e r m i n a t i o n o f b a c t e r i a l ,
numbers i n t h e s o i l i s w o r th le s s e,s an a tte m p t in i n t e r p r e t i n g s o i l phe­
nomena.

However, l a t e r s t u d i e s h ave c l e a r l y p ro v e n t h a t s t u d i e s on th e

numbers o f o rg a n is m s a r e im p o r ta n t and i n d i c a t i v e when u s e d in c o n ju n c t io n
w ith o t h e r e d a p h ic and c l i m a t i c c o n s i d e r a t i o n s .

I n comparing numbers o f

b a c t e r i a , no s i n g l e v a r i a b l e su ch as s e a s o n of th e y e a r can be c o n s id e r e d
a lo n e w i t h o u t r e f e r e n c e to m o is tu r e c o n t e n t , a c i d i t y , and o t h e r f a c t o r s
as shown by Waksman (1927)*

S tu d i e s o f s o i l o rg a n ism s in n a t u r a l and

p l a n t e d f o r e s t s t a n d s by Shipman (19^7) have shown t h a t s i t e q u a l i t y i s
d e f i n i t e l y r e l a t e d t o s o i l o rganism p o p u l a t i o n s .

Most of th e b a c t e r i a

i n t h e s o i l d e v e lo p b e s t a t r e a c t i o n s o f a c i d i t y c l o s e to n e u t r a l i t y
(pH 7.0)

The amount o f f r e e a i r w ith p o s s i b l e a c c e s s t o b a c t e r i a may

d e te r m in e th e ty p e o f h e t e r o t r o p h i c b a c t e r i a t h a t d e v e lo p , e i t h e r a e r o b i c
or a n a e ro b ic .

As f a r a s m o is tu r e c o n te n t i s c o n ce rn e d , a l l b a c t e r i a

r e q u i r e a c o n s i d e r a b l e s u p p ly o f w a te r f o r a c t i v e developm ent and i s o f t e n
a l i m i t i n g f a c t o r in th e numbers o f b a c t e r i a p r e s e n t .
S in c e t h e a c tin o m y c e te s a r e n e x t to the b a c t e r i a in number of forms
d e v e lo p i n g on t h e p l a t e s , t h e y a r e im p o rta n t in the a d d i t i o n o f m y c e lia
to t h e s o i l .

Here a g a i n , l a r g e numbers do not n e c e s s a r i l y i n d i c a t e more

a b u n d a n t g r o w th , b u t a r e s u l t of a g r e a t e r abundance o f c o n i d i a .

I t is

w e ll t o remember t h a t g r e a t e r abundance r e p r e s e n t s a g r e a t e r p o t e n t i a l
a c t i v i t y o f o rg a n is m s .

The p e r c e n ta g e of a c tin o m y c e te s xn f o r e s t s o i l s

in r e l a t i o n to th e number o f b a c t e r i a i s im p o rta n t i n s o f a r a s d e c o m p o s itio n
o f o r g a n i c m a t t e r in th e s o i l i s c o n c e rn e d .

A ctin om y cetes a r e v e ry

s e n s i t i v e to a c i d i t y and to an e x c e s s o f m o is tu r e and th e numbers d e c r e a s e
in s o i l s d e v o id o f decomposed m a t e r i a l ,

in com parison w ith th e b a c t e r i a .

231

As a g e n e r a l r u l e , th e l e s s a c i d th e s o i l th e h i g h e r i s th e r e l a t i v e
abundance o f a c t i n o m y c e t e s ,

Most o f th e a c tin o m y c e te s a r e a e r o b i c and

a s a r u l e a r e more s e n s i t i v e t o changes in r e a c t i o n and l i v e o v e r a
n a r r o w e r ra n g e o f a c i d i t y and a l k a l i n i t y th a n th e b a c t e r i a as shown by
Ifaksman an d S ta r k e y ( I 9 3 I ) .
S i g n i f i c a n t R e s u l t s on B a c t e r i a and A c tin o m y c e te s:
1.

The t o t a l r e l a t i v e numbers of b a c t e r i a and a c tin o m y c e te s
o c c u r r i n g in two p l a n t a t i o n s i t e s , A rea X and A rea Y, were
n o t s i g n i f i c a n t l y d i f f e r e n t f o r an e n t i r e growing s e a s o n ,
in f o u r s o i l h o r iz o n s i n v e s t i g a t e d .

T h is s i m i l a r i t y i n

q u a n t i t y o f o rg a n ism s can be s e e n in T ab les 52 and 53 an^F ig u r e s 50-53*
2.

A s l i g h t l y g r e a t e r t o t a l number o f b a c t e r i a o c c u r r e d in
A rea Y f o r t h e e n t i r e s o i l p r o f i l e th ro u g h o u t th e growing
season.

The t o t a l a c tin o m y c e te p o p u l a t i o n was g r e a t e s t in

A re a X,
3.

B a c t e r i a o c c u r r e d in th e g r e a t e s t t o t a l numbers o f o rg an ism s
th a n any o f th e t h r e e groups of organism s s t u d i e d .

T his was

t r u e f o r b o t h A rea X and Area Y.
The g r e a t e s t number o f b a c t e r i a p e r gram o f s o i l f o r A rea X
o c c u r r e d in th e A h o r iz o n , where th e co u nt r i s e s to 1,7^+1,620
o
n e r gram o f s o i l .
was fo u n d in th e

F o r Area Y, the g r e a t e s t b a c t e r i a c o un t
h o r i z o n , where th e co u n t r i s e s to

2 , 0 ^ 3 ,7 5 0 p e r gram of s o i l ,

5,

The g r e a t e s t number o f a c tin o m y c e te s f o r A rea X o c c u r r e d in
th e "b

h o r i z o n , where th e count was 71*^20 p e r gram o f s o i l .

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23^

F o r A re a Y, th e g r e a t e s t a c tin o m y c e te p o p u l a t i o n v/as found in
th e Aq h o r i z o n , where t h e co u n t r i s e s to 62,120 p e r gram.
6.

I n A re a X, th e " b a c te r ia l p o p u l a t i o n in th e s u r f a c e h o r i z o n s ,
Aq and A^, was g r e a t e s t in t h e s p r i n g , d rop p ed to a minimum
in mid-summer, and re a c h e d a se c o n d a ry maximum in e a r l y autumn.
I n A rea Y, however, th e b a c t e r i a re a c h e d a maximum in e a r l y
summer, a m inimu m in mid—summer, and a se c o n d a ry maximum in
e a r l y autumn.

I n b o th Area X and Y, th e a c tin o m y c e te s

fo llo tu e d much th e same s e a s o n a l f l u c t u a t i o n a s th e f u n g i .
C o n c lu sio n s R eg ard in g B a c t e r i a and A ctinom ycete R e s u l t s :
The e f f e c t s o f y e a r s o f i n j u d i c i o u s cro p p in g w ith o u t f e r t i l i z a t i o n
o f any k i n d i s s t r i k i n g l y p o r t r a y e d by th e r e l a t i v e l y lovr b a c t e r i a l c o u n ts
o f t h i s s t u d y , ta k e n th ro u g h o u t t h e grow ing s e a s o n .

The s i m i l a r i t y in

t o t a l numbers o f b a c t e r i a and a c tin o m y c e te s f o r b o th Area X and A rea Y
te n d s t o p o i n t o u t ( a s w ith t h e f u n g a l p o p u la tio n ) t h a t th e s e two s i t e s
a r e e s s e n t i a l l y m i c r o b i o l o g i c a l l y s i m i l a r and t h a t t o t a l organism
e q u i l i b r i u m i s b e in g e s t a b l i s h e d a t a low Q u a n t i t a t i v e l e v e l i n b o t h s i t e s .
As w i t h t h e f u n g i , t h e t o t a l b a c t e r i a l p o p u l a t i o n i s s l i g h t l y h i g h e r in
A rea Y th a n

in A rea X.

The c o r r e l a t i o n o f m ic ro c lim a t ic f a c t o r s f o r th e

A and A^ i s m arkedly shown by comparing th e s e two h o r i z i o n s in each

area.

I n A re a X, th e g r e a t e s t b a c t e r i a l p o p u l a t i o n i s fo u n d in th e Aq h o r iz o n ,
w ith a v e r y low c o u n t in th e
i s fo u n d in th e A-j_ h o r i z o n .

in A rea Y, the g r e a t e s t b a c t e r i a l count
This r e s u l t i s c l e a r l y a f u n c t i o n of th e

g r e a t e r a v a i l a b l e s o i l m o i s t u r e , lo w e r e v a p o r a tio n r a t e , low er s o i l s u r f a c e
t e m p e r a t u r e s and h i g h e r r e l a t i v e h u m id ity of A rea X.

The canopy o f th e

t r e e crowns in A rea X i s a p o t e n t f a c t o r i n p r e v e n t i n g t h e e f f e c t of the

F ig .

56

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Air Temperature

85
80
75

70
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# 90

10

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12

20

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70
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Spring
July 21
June 22
June 2

Aug. 21

Early Autumn '
Sept. 14

THE RELATION BETWEEN NUMBERS OF ORGANISMS AND
MICROCLIMATE IN THE AREA OF GOOD HEIGHT GROWTH OF TULIP POPLAR

Pl.cr. 57 .

236

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E a r l y Summer
J u l y 21

I E a r l y Autumn
Aug. 21

THE DELATION BETWEEN NUMBERS OF ORGANISMS AND
MICROCLIMATE IN THE AREA OF POOR HEIGTTT GROWTH OF TULIP POPLAR

237

sun * s r a y s from

e v a p o r a tin g s o i l m o is tu r e d u r e c t l y a t th e s u rfa ,c e .

In

t h e more a r i d s o i l o f A rea Y, l a c k i n g su ch a p r o t e c t i v e l a y e r , th e number
o f b a c t e r i a a t t h e s u r f a c e i s l e s s , due to d e s i c c a t i o n e f f e c t s .

In a d d itio n

to m o i s t u r e c o n t e n t o f th e s u r f a c e h o r i z o n s , t h e s o i l s o f A rea X more
c l o s e l y a p p ro a c h a n e u t r a l o r l e s s a c i d c o n d i t i o n th a n th e s u r f a c e s o i l s
o f A re a Y.

A n e a r p e r f e c t c o r r e l a t i o n w i t h i n c r e a s e d d e p th o f h o r iz o n

i n A re a X i s i l l u s t r a t e d i n F i g u r e 5^*

These two f a c t o r s , m o is tu r e c o n t e n t

and s o i l a c i d i t y , a r e th u s i n c l o s e r e l a t i o n s h i p to th e o t h e r m i c r o c l i m a t i c
f a c to r s of th e in d iv id u a l a re a s.
(b a c te ria )

Here a g a in , by u s in g a m i c r o b i a l f a c t o r

i t i s p o s s i b l e to p o i n t o u t t h a t th e s o i l m o is tu re regim en,

a s a f u n c t i o n o f e x t e r n a l e d a p h ic a n d c l i m a t i c f a c t o r s , i s l i m i t i n g w ith
r e s p e c t to t h e s e t u l i p p o p l a r s i t e s .

As w ith th e f u n g a l r e s u l t s , th e

g r e a t e r b a c t e r i a l p o p u l a t i o n o f A rea Y cann o t be a s s o c i a t e d q u a n t i t a t i v e l y
w ith t h e p o o r h e i g h t gro w th of t u l i p p o p l a r , s i n c e A rea X p o s s e s s e s a
lo w e r m i c r o b i o l o g i c a l c o u n t.
I n r e g a r d to t h e a c ti n o m y c e te s , t h e l a r g e r t o t a l number fo u n d i n t h e
s u r f a c e h o r i z o n s o f A rea Y s u g g e s ts th e c lo s e r e l a t i o n s h i p to th e f u n g i
w i t h r e s u e c t to o r g a n i c m a t t e r , a v a i l a b l e oxygen, and s o i l a c i d i t y .

The

d e c r e a s e in numbers o f a c tin o m y c e te s w ith d e p th u n t i l th e B^ h o r iz o n i s
r e a c h e d , in A rea X, i s a s s o c i a t e n r a t h e r c l o s e l y w itn t h e more a c i d
c o n d i t i o n s a.t g r e a t e r d e p t h s , to th e p o s s i b l e washing down o f th e c o n i d i a
o r t o th e g r e a t e r r e s i s t a n c e o f t h e s e organism s to a l a c k o f oxygen.
The q u a n t i t a t i v e r e s u l t s o b ta in e d h e re f o r t h r e e d i s t i n c t g ro u p s o f
s o i l o rg a n ism s show t h a t th e b a c t e r i a a r e most s e n s i t i v e to m ic r o c l i m a t i c
f a c t o r s f o r u se as s u p p le m e n ta l e v id en c e in e v a l u a t i n g p l a n t a t i o n s i t e
a u a lity .

T his e v id e n c e is b a s e d upon th e p l a t e c ou nt method o f i s o l a t i n g

F ig .

58.

B a c t e r i a and a c tin o m y c e te c o lo n ie s shoving th e r e l a t i v e
d e n s i t y o f organism s by s o i l h o riz o n f o r th e a r e a of good
h e i g h t gro w th (A rea X). These s o i l m ic r o b i a l i s o l a t i o n s
were made i n th e S p rin g (May 20, 1951)* A n e a r l y p e r f e c t
c o r r e l a t i o n w ith i n c r e a s e d d e p th o f h o r iz o n i s i l l u s t r a t e d
by t h i s p l a t e c o u n t; th e numbers o f b a c t e r i a d e c r e a s e w ith
i n c r e a s e d d e p th in a l l t h r e e d i l u t i o n s . The a c tin o m y c e te
c o u n ts d e c r e a s e w i t h d e p th u n t i l th e B2 h o riz o n i s re a c h e d ,
i l l u s t r a t i n g t h e i r ten d en c y to fo llo w th e t r e n d o f f u n g i
f o r s i m i l a r h o r i z o n s . The h ig h e r b a c t e r i a l count o f t h e
A0 and
h o r iz o n s as shown above is c l o s e l y r e l a t e d to th e
more aJLkaline c o n d i t i o n s of th e s u r f a c e s o i l a s c o n t r a s t e d
to th e more a c i d c o n d i t i o n s a t g r e a t e r d e p th s in t h i s a r e a .

239

o r g a n is m s , a s u s e d in t h i s s tu d y .

The c o u n ts made f o r each group of

o rg a n is m s a r e ha.sed upon th e a v e ra g e v a lu e o f s i x d u p l i c a t e p l a t e s f o r
e ach s o i l h o r iz o n t a k e n f o u r tim e s th ro u g h o u t t h e growing s e a s o n , o r
t h e a v e r a g e of f o r t y - e i g h t c o u n ts .

SUMMARY MD COHOLUSIOKS
A co m p reh en siv e i n v e s t i g a t i o n of th e e d a p h ic , m icroclim a,t i c , and
m i c r o b i o l o g i c a l f a c t o r s c o n t r i b u t i n g to t h e d i f f e r e n t i a l h e i g h t g ro w th o f
p l a n t a t ion-grow n t u l i p p o p l a r (L ir io d e n d r o n t u l i p i f e r a L .) was u n d e r ta k e n .
T h is s i l v i c a l s t u d y was cond ucted a t th e F red Russ E x p e rim e n ta l F o r e s t in
Cass C ounty, M ich ig an , d u rin g t h e growing s e a so n s o f 1951 an<! 1952.

The

i n v e s t i g a t i o n i n c l u d e s th e r e s u l t s o f s t u d i e s made b o th i n th e f i e l d and
i n t h e l a b o r a t o r y in an e f f o r t to d e te rm in e th e s i l v i c a l r e q u ire m e n ts o f
p l a n t a t i o n —grown t u l i p p o p l a r .

S in c e a l a r g e a c re a g e of Russ F o r e s t i s

p l a n t e d to t u l i p p o p l a r in v a r i o u s m ix tu r e s , a, knowledge of th e g ro w th
h a b i t s o f t h i s s p e c i e s u n d e r th e c l i m a t i c c o n d i t i o n s o f s o u th w e s te rn
M ich ig an seemed a d v i s a b l e .

In a d d i t i o n , t h i s l o c a l i t y o f M ichigan

p o s s e s s e s a l a r g e number o f fo rm e rs and p r i v a t e owners who a r e i n t e r e s t e d
i n c o n v e r t i n g abandoned farm la n d i n t o t r e e farm s a s a c o n tin u e d in v e s tm e n t.
The p r e s e n t s tu d y was i n i t i a t e d to d e te rm in e th e f e a s i b i l i t y o f recommending
t u l i p p o p l a r p l a n t i n g s f o r such e n t e r p r i s e s .
The r e s e a r c h work was c a r r i e d o u t on a 15 y e a r o ld —20 a c r e t u l i p
p o p la r-c a ta lp a p la n ta tio n .

O b s e rv a tio n of th e t u l i p t r e e s in t n i s

p a r t i c u l a r p l a n t a t i o n show marked d i f f e r e n t i a l r a t e s o f h e i g h t grow th on
t r e e s o f t h e same age and d e n s i t y .

T h is d i f f e r e n c e in t n e h e i g h t g ro w th

i s a s s o c i a t e d w ith t h e p re s e n c e o f an o ld —growth nardwood s t a n d a d j o i n i n g
th e n l a n t a t i o n on t h e s o u th ano. w e s t.

Trees l o c a t e d n e x t to t h e s e woods

a r e one and o n e - h a l f to two tim es th e h e i g h t o f t r e e s n o r t h o f th e woods.
The p l a n t a t i o n was th u s c o n v e n ie n tly d iv id e d i n t o two s e p a r a t e a r e a s f o r

2kl

r e s e a r c h purposes*

The area e x h ib i t in g good h e ig h t growth was d e s ig n a te d

as Area X; th e area o f poor h e ig h t growth was d e sig n a te d as Area Y.

A ll

ed ap h ic, m ic r o c li m a t ic , and m ic r o b io lo g ic a l da,ta were obtained at the
same s t a t i o n s e s t a b l i s h e d in both a r e a s .

Maps, photographs, and s t r a i g h t -

l i n e t r a n s e c t s were made in the p la n t a t io n showing the c l i m a t i c s t a t i o n s ,
b o u n d e r ie s , and s o i l s of th e experim ental a r e a s.

A s t a t i s t i c a l a n a ly s is

o f v a r ia n c e was a p p lie d to th e r e s u l t s o f th e p h y s ic a l and chemical s o i l
fa cto rs.
The la b o r a to r y experiments on th e p h y s ic a l-e d a p h ic f a c t o r s on the
two s i t e s , Area X and Area Y, r ev e a le d only two p r o p e r tie s o f an a c tu a l
and s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e between the two a r e a s .

These

two f a c t o r s , th e amount o f f i n e c la y and the \tfater-holding c a p a c ity , were
the o n ly two v a r ia b le s which d if f e r e d s i g n i f i c a n t l y between Area X and
Area Y.

Ten p h y s ic a l-e d a p h ic p r o p e r tie s were s tu d ie d in d e t a i l and

tr e a t e d s t a t i s t i c a l l y .

The p h y s ic a l s o i l f a c t o r s in v e s t ig a t e d were s o i l

t e x t u r e , s p e c i f i c g r a v i t y , volume w eigh t, p o r o s it y , hygroscopic c o e f f i c i e n t ,
w a te r -h o ld in g c a p a c it y , m oisture e q u iv a le n t, s o i l evaporation l o s s , depth
o f r o o t p e n e t r a t io n , and the w a te r -ta b le f l u c t u a t i o n .
Laboratory experim ents on the chem ical—edaphic f a c t o r s o f the s o i l s
in each area were tr e a t e d s t a t i s t i c a l l y m tne same manner a.s the p h y s ic a l
fa cto rs.

A summation o f s i x ra th er important major chemical s o i l p r o p e r tie s

such as s o i l a c i d i t y , organic matter co n te n t, t o t a l n itr o g e n , cat ion-exchange
c a p a c it y , t o t a l b a s e s , and base s a tu r a tio n , in d ic a te d no outstan din g r e a l
or s t a t i s t i c a l l y s i g n i f i c a n t d if f e r e n c e between the areas of good and poor
h e ig h t growth o f t u l i p p o p la r ,

fu r t h e r v e r i t i c e t i o n of the la c k of any

o u tsta n d in g chemical d if f e r e n c e was s u b s ta n tia te d by a study o f seven
in d iv id u a l major n u t r ie n t e l e m e n t s .

2k 2

The f i e l d experim ents concerned with, m ic r o clim a te , growth r a t e s ,
s u n s c a ld , hark t h ic k n e s s , and p la n t s u c c e s s io n ivere found to he more
c l o s e l y a s s o c i a t e d w ith the growth d i f f e r e n t i a l than e itiie r th e physical,
or chem ical edaphic fa ,c to r s .

A complete stem a n a ly s is o f in d iv id u a l

t r e e s in hoth a reas r e v e a le d the e x te r n a l e f f e c t s o f s i t e upon r a d ia l
and h e ig h t growth r a t e s .

The p h y s i o l o g i c a l "dryness” of the s i t e in

Area Y i s r a th e r c l e a r l y d i s c l o s e d hy the s t r u c t u r a l v a r ia t io n of the
hark o f t r e e s in t h i s a r e a .
The e f f e c t o f the growing season p r e c i p i t a t i o n and temperature on
the h e ig h t and diam eter growth o f t u lip poplar f o r a 11-year p erio d was
undertaken.

By use o f the c o r r e la t io n c o e f f i c i e n t and p a s t records o f

the U. S. Weather Bureau, i t was p o s s i b l e to show th e e f f e c t of accumu­
l a t i v e growing season p r e c i p i t a t i o n and temperature upon the h e ig h t growth
o f t u l i p p o p la r f o r hoth Area X and Ares, Y.

Although hoth ares.s were

l i n e a r l y dependent upon growing season p r e c i p i t a t i o n , Area Y was found
to he l e s s e f f e c t i v e in i t s u t i l i z a t i o n o f r a i n f a l l throughout the
growing s e a s o n .

A supplem ental study on the r a d ia l growth of t r e e s in

th e a d j o in in g old-grow th hardwoods showed no c lo s e c o r r e la t io n to growing
sea so n p r e c i p i t a t i o n throughout a s im ila r p e r io d .

The extreme sunscald

e x h ib i t e d hy t r e e s in Area Y was in v e s t ig a t e d and the r e s u l t s r e v e a l the
i n d i r e c t e f f e c t s o f exposure, ev ap oration , a ir temperatures and wind
v e l o c i t y upon th e h e ig h t growth o f t u l i p pop lar.

A study o f th e herbaceous

v e g e t a t io n in r e l a t i o n to the s o i l moisture c o n d itio n s o f each area was
c a r r ie d out to c o r r e l a t e the type or kind o f v e g e t a tio n a s s o c ia t e d w ith
a o a r tic u la r h a b ita t.

The r e s u l t s tend to show a c o r r e la t io n between

2^3

s o i l m o istu re c o n d it io n s o f each area and the kind o f herbaceous v e g e t a t io n
in d igen ou s to th e s i t e .
The growing sea so n study o f seven m ic r o c lim s t ic f a c t o r s in Area X
and Area Y in d ic a t e d in v i r t u a l l y every case th at the in te g r a te d f a c t o r s
o f e v a p o r a tio n , r e la /tiv e hum idity, a i r temperature, su r fa c e s o i l tempera­
tu r e , p e r c e n t a v a i l a b l e m oistu re, and l i g h t i n t e n s i t y are c l o s e l y r e la t e d
to th e marked d i f f e r e n t i a l h e ig h t groKth o f t u l i p p op la r.

The above

f a c t o r s Kere measured d a i l y throughout the growing sea so n , w ith th e
e x c e p t io n o f l i g h t i n t e n s i t y .
As a means o f fu r t h e r corrob o ra tin g the fin d in g s o f the c l i m a t i c
and edaphic f a c t o r s , a q u a n t it a t iv e s o i l m ic r o b io lo g ic a l study was under­
taken.

The r e s u l t s o f t h i s in v e s t igat ion show how numbers o f c e r t a in

groups o f s o i l organisms can be u t i l i z e d to supplement and v e r i f y other
s i t e q u a lity fa c to r s .

R e su lts on the r e l a t i v e numbers of organisms found

in ea.ch area, p o in t out th e manner in which one s i t e v a r ia b le can be
masking the e f f e c t o f another vrith regard to p o s s i b l e l i m i t i n g f a c t o r s .
Area, Y was found to be m ic r o b io lo g ic a lly more s u i t a b l e to the growth o f
t u l i p p op lar in terms o f organism numbers, and y e t t h i s a rea i s producing
the p o o r e s t t r e e s .

The manner in which th e m oisture regimen i s over­

r id in g th e e f f e c t s o f s o i l f e r t i l i t y and improved s o i l te x tu r e i s c l e a r l y
r e v e a le d by t h i s s tu d y .

A ls o , i t was p o s s ib le to show how th e m ic r o b ia l

p o p u la tio n f l u c t u a t e s throughout th e growing season under a s e t o f
s im u lta n e o u s ly in v e s t i g a t e d v a r i a b l e s .

S o il organism numbers were shorn

to be supplem ental in d ic e s to the f o r e s t e r * s concept of s i t e q u a lit y in
terms o f t r e e growth.

2bk

Thus, e v id en ce "based upon a comprehensive study of the s i l v i c a l
requirem ents o f p la n ta tio n -g r o v n t u l i p poplar* shows th a t th e continuous
s o i l - m o i s t u r e regimen throughout th e growing season i s the p r in c ip a l
l i m i t i n g f a c t o r c o n tr ib u tin g to th e marked d i f f e r e n t i a l h e ig h t growth
of th is sp e cie s.
The p r e se n c e o f an old-grow th hardwood stand a d jo in in g the south and
west s i d e s o f the experim ental p l a n t a t io n a l t e r s the s o il- m o i s t u r e regimen
under a s e t o f in t e g r a te d edaphic, m ic r o c lim a tic , and b i o l o g i c a l c o n d it io n s .
This in f lu e n c e o f the old—growth hardwoods serves to d i s c l o s e th e e c o l o g i c a l
c o n t r a s t between good and poor s i t e s o f t u l i p p o p lar.
The s i l v i c a l c h a r a c t e r i s t i c s of young pla n ta tio n -gro w n t u l i p p o p lar,
as shown by t h i s stu d y , in d ic a te s t h i s s p e c ie s an being c r i t i c a l , s e n s i­
t i v e , and e x a c t in g w ith regard to i t s s i t e requirements a t the f r in g e o f
i t s g e o g r a p h ic a l range.
In th e e sta b lish m e n t o f p la n ta t ion-grown t u lip poplar under the
edaphic and c l i m a t i c c o n d itio n s o f southwestern Michigan, the f o r e s t e r
should g i v e primary c o n s id e r a t io n to the s o il- m o is t u r e regimen o f t h i s
sp e cie s.

The r e s u l t s o f t h i s i n v e s t i g a t i o n emphasizes the importance o f

s o i l m o istu re in r e l a t i o n to border p la n t in g s , drainage, and exposure fo r
proposed t u l i p p op lar p l a n t a t i o n s .
For maximum developm ent, t h i s s p e c ie s req u ires s id e —srading and
p r o t e c t i o n in i t s e a r l y p la n ta tio n e sta b lis h m e n t.

Eased upon th e s e

s i l v i c a l f i n d i n g s , i t i s recommended th a t t u lip poplar be in t e r p la n te d
w ith a p r e v io u s ly e s t a b l i s h e d s p e c i e s , such as w hite p in e , red p in e , or
o th er s p e c i e s .

T ulip poplar should be in te r p la n te d only when the

"nurse tr e e s " are o f s u f f i c i e n t s i z e to g iv e maximum s id e p r o t e c t io n to

2^5

t h i s sp ecies*

As t h e t u l i p t r e e s r e a c h a s i z e v'hen s i d e - s h a d i n g i s no

l o n g e r r e q u i r e d , th e “n u r s e t r e e s 11 can h e removed i f p u re t u l i p i s
d e sired .

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