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University Microfilms International 300 N. Zeeb Road Ann Arbor, Ml 48106 8503268 R o s e , W illard My BIOMASS, NET PRIMARY PRODUCTION AND SUCCESSIONAL DYNAMICS OF A VIRGIN WHITE PINE (PINUS STROBUS) STAND IN NORTHERN MICHIGAN Michigan State University University Microfilms International 300 N. Zeeb Road, Ann Arbor, Ml 48106 Ph.D. 1984 BIOMASS, NET PRIMARY PRODUCTION AND SUCCESSIONAL DYNAMICS OF A VIRGIN WHITE PINE ( PINUS STROBUS) STAND IN NORTHERN MICHIGAN By W i l l a r d M. Rose A DISSERTATION S u b m i tt e d t o Michigan S t a t e U n i v e r s i t y in p a r t i a l f u l f i l l m e n t of the requirements f o r t h e d e gre e of DOCTOR OF PHILOSOPHY Department of Botany and P l a n t P a th o lo g y 1984 ABSTRACT BIOMASS, NET PRIMARY PRODUCTION AND SUCCESSIONAL DYNAMICS OF A VIRGIN WHITE PINE ( PINUS STROBUS) STAND IN NORTHERN MICHIGAN By W i H a r d M. Rose E a s t e r n w h i t e p i n e ( Pi nus s t r o b u s L . ) , a v e r a g i n g 177 y e a r s in a g e , dom ina te s t h e f o r e s t a t Hartwick P i n e s S t a t e P a r k , Michigan, with a basal a r e a o f 4 8 .4 m2/ h a , 66.7% o f t h e t o t a l . I t s mean d i a m e t e r and h e i g h t were 58 cm and 36 m, r e s p e c t i v e l y . Biomass and ne t p ri m a ry p r o d u c t i o n were e s t i m a t e d u s i n g s t a n d a r d nondestructive techniques. To ta l t r e e biomass f o r t h e s t a n d was 681 m t / h a , u s i n g a measured w h i t e pin e wood d e n s i t y of 0 . 2 9 g/cm2 , or 800 m t/ h a u s i n g a d e n s i t y v a l u e of 0.37 g/cm2 from t h e l i t e r a t u r e . With few e x c e p t i o n s , H a r t w i c k ' s t o t a l biomass and b a s a l a r e a (7 2 . 6 m2/ h a ) a r e among t h e h i g h e s t r e p o r t e d in t h e l i t e r a t u r e f o r f o r e s t s worldwide. T o t a l n e t prim ary p r o d u c t i o n of t r e e s , on t h e o t h e r hand, was a r e l a t i v e l y low 7 . 5 m t / h a / y r . Diameter and h e i g h t d i s t r i b u t i o n s of mature t r e e s and s e e d l i n g dynamics were i n v e s t i g a t e d t o d e t e r m i n e t h e s u c c e s s i o n a l s t a t u s o f t h i s stand. D ia mete r and h e i g h t d i s t r i b u t i o n s s u g g e s t t h a t re d maple, sug ar maple and beech a r e s u c c e e d i n g w h i t e p i n e . The l a r g e number o f red maple s e e d l i n g s and t h e l a r g e crowns of s u g a r maple s e e d l i n g s may c o n t r i b u t e t o t h e e v e n t u a l s u c c e s s by maples in dom ina tin g t h e s t a n d . The l a r g e crowns o f s u g a r maple s e e d l i n g s may a l s o account f o r t h e i r g r e a t e r r a t e o f shoot growth. White p in e s e e d l i n g s were as numerous as s u g a r maple but grew poorly. A s tu d y o f d i f f e r e n t - a g e d gaps in t h e w hi te pi ne canopy i n d i c a t e d t h a t o n l y maples s u r v i v e d p a s t t h e s e e d l i n g s t a g e , f i l l i n g in W i l l a r d M. canopy gaps a f t e r a p p r o x i m a t e l y 50 y e a r s . Rose A s s o c i a t e d with c l o s i n g of canopy gaps was a d e c r e a s e in s e e d l i n g a v e r a g e ag e, h e i g h t , b a s a l d i a m e t e r , crown c o v e r , s ho ot growth and p e r c e n t a g e of s e e d l i n g s browsed by d e e r . F u r t h e r , i t a p p e a rs t h a t maple s e e d l i n g s do not do as well under a maple canopy as compared t o a pin e canopy or gap. See ding s u r v i v o r s h i p was g r e a t e r in t h e gaps th a n under t h e canopy and g r e a t e r d u r i n g w i n t e r t h a n summer. Sugar maple had t h e h i g h e s t o v e r a l l annual s u r v i v a l r a t e (90.2%) and red maple had t h e lowest (79.6%). Maple n a t a l i t y was 1 .3 /m 2/ y r in t h e gap and 1. 5/m 2/ y r under t h e canopy. White p in e and hemlock combined n a t a l i t y was 11.25/m2/ y r , but t h e r e was 100% m o r t a l i t y , p o s s i b l y due t o mechanical damage. In comparing s e e d l i n g dynamics among t h r e e s i t u a t i o n s ( w i t h i n a canopy gap, under t h e f o r e s t canopy, and i n an open a r e a where w h it e p in e were r e g e n e r a t i n g ) , t h e w hit e pin e r e g e n e r a t i o n s i t e had t h e low est humid ity and h i g h e s t a i r t e m p e r a t u r e and s o l a r i n s o l a t i o n . Deer a re b e l i e v e d t o r e t a r d s u c c e s s i o n by browsing a high p e r c e n t a g e of s e e d l i n g s . R e s u l t s o f a p a i r e d p l o t e x c l o s u r e s tu d y r e v e a l e d no s i g n i f i c a n t d i f f e r e n c e s in l e n g t h o f sho ot growth between browsed and unbrowsed ma ple s. There was a s i g n i f i c a n t i n c r e a s e i n h e i g h t and crown c o v e r of unbrowsed maple s e e d l i n g s be cause sh oo t l e n g t h had not been re duc ed by br ow s in g. These i n c r e a s e s c ou ld have r e s u l t e d in i n c r e a s e d c o m p e t i t i o n which le d t o d e c r e a s e d s u r v i v a l o f w hi te pin e in unbrowsed areas. I t was co n clud e d t h a t a p o s s i b l e s u c c e s s i o n a l s e r i e s f o r t h i s a r e a , i f u n i n t e r u p t e d by f i r e o r o t h e r d i s t u r b a n c e , would be: j a c k p in e f o r t h e f i r s t 80 y e a r s , w h it e p in e f o r 170 y e a r s , w hit e p i n e - n o r t h e r n hardwoods f o r 200 y e a r s , h e m l o c k - n o r t h e r n hardwoods f o r 200 y e a r s w it h Wi11ard M. Rose maple dominated hardwoods f o l l o w i n g as a long t e r m s t a b l e community. It i s h y p o t h e s i z e d t h a t biomass would i n c r e a s e t o a maximum when w h i t e pine dominated and t h e n d e c r e a s e when hardwoods assumed dominance. F i r e was t h e most obvious d i s t u r b a n c e f a c t o r t h a t he lp ed m a i n t a i n w h it e p in e as a dominant s p e c i e s i n t h i s a r e a p r i o r t o l u m be ri ng . TO LINDY ACKNOWLEDGEMENTS The p l a n n i n g , c o n d u c t i o n , and co m p le ti o n o f any r e s e a r c h p r o j e c t u s u a l l y i n v o l v e s t h e a s s i s t a n c e of numerous p e r s o n s and t h i s acknowledge­ ment s e c t i o n is an a t t e m p t t o r e c o g n i z e t h o s e i n d i v i d u a l s . Throughout t h e c o u r s e of t h i s p r o j e c t ny a d v i s o r , Dr. P e t e r G. Murphy, was a c o n s t a n t s o u r c e o f en co ura ge me nt, s u p p o r t , and p r o f e s s i o n a l a s s i s t a n c e , w i t h o u t which t h i s st ud y would have been f a r l e s s p r o d u c t i v e and e n j o y a b l e . Dr. J a y R. Harman, Dr. Donald I . Dickman, Dr. Stephen N. S te p h e n s o n , and Dr. G e r h a r d t S c h n e i d e r not onl y c o n t r i b u t e d g r e a t l y t o t h i s p r o j e c t as committee members, but t o my o v e r a l l academic e n l i g h t e n ­ ment as w e l l . I am de ep ly i n d e b t e d t o ny f e l l o w e co lo gy g r a d u a t e s t u d e n t s , Gerard D o n n e l l y , Dr. W ill ia m L a r s e n , Michael S c o t t , Dr. C h r i s t o p h e r Uhl and Lois Wolfson f o r t h e i r h e l p f u l s u g g e s t i o n s , encouragement and re v ie w o f t h e manuscript. Our i n t e r a c t i o n and f r i e n d s h i p was a most memorable and enjoyable experience. The p a r t i c i p a t i o n of t h e f o l l o w i n g u n d e r g r a d u a t e e co lo gy s t u d e n t s added a dimension t o t h i s r e s e a r c h t h a t is g r e a t l y a p p r e c i a t e d : John B i a n c h i , David B uch ne r, Ro ber to M. D ia z, Robert J . D i e d e r i c h , B i l l Emery, Carolyn F i r t h , T e r r y H i l l e g a s , Deborah J . Hyde, Marla K. J e n k i n s , Frank K e l l y , Karen S . La Mere, Kathryn A. L a u g h l i n , Thom Law, Mike Lozen, Lindy M e i t z , M i c h e l l e A. M e r r i t t , David R. M ic he ls on , Michael Myers, Lynn V. P r i n d l e , Michael S. Savage, Binger S . W in c h e ll , C a t h e r i n e Wolfe, and Thomas Yocum. I would a l s o l i k e t o thank Wendel Hoover f o r our e n l i g h t e n i n g and e n t e r t a i n i n g d i s c u s s i o n s a bo ut Hartwick Pines and lumbe ring h i s t o r y . My s i n c e r e g r a t i t u d e goes out t o P h y l l i s R o b e r t s o n , f r i e n d and g u i d e , and P a t r i c e P e r k i n s and Marianne La Haine f o r t h e i r s p e c i a l c o n t r i b u t i o n s in c o m p l e t i n g t h i s p r o j e c t . I wish I could more a d e q u a t e l y e x p r e s s ny s i n c e r e th a n k s t o my p a r e n t s , Robert and Lenore Rose, f o r t h e i r s u p p o r t and i n s p i r a t i o n , and h a vin g i n s t i l l e d in me t h e v a lu e s and s e l f image t h a t en ab le d me t o be gi n my g r a d u a t e c a r e e r . Not enough can be w r i t t e n t o a d e q u a t e l y show my a p p r e c i a t i o n t o ny w i f e , Lindy M. Rose, f o r h e r e n d u r i n g l o v e , p a t i e n c e and u n d e r s t a n d i n g , even t o t h e p o i n t of s a c r i f i c e . I t was he r a s s i s t a n c e and s u p p o r t t h a t e n a b le d me t o f i n i s h t h i s p r o j e c t . To a l l who h e l p e d , I th a n k you. TABLE OF CONTENTS Page LIST OF TABLES ................................................................................................................... vi LIST OF FIGURES ................................................................................................................. v i i i INTRODUCTION ........................................................................................................................ 1 METHODS AND MATERIALS ............................................................. '..................................... 7 Community D e s c r i p t i o n ........................................................................................ Biomass and P r o d u c t i v i t y ................................................................................. S t e m ............................................... Branch ............................................................................................................... F o l i a g e ................................................................................................... Root ................................................................................................................... S u c c e s s io n ................................................................................................................. Tree d i a m e t e r , h e i g h t and age d i s t r i b u t i o n .............................. Canopy gap d e s c r i p t i o n ........................................................................... S e e d l i n g d e s c r i p t i o n , age and s i z e d i s t r i b u t i o n ................... S u r v i v o r s h i p ................................................................................................. Envi ronm en tal p a r a m e t e r s ...................................................................... Deer b r o w s i n g ............................................................................................... White p in e r e g e n e r a t i o n ......................................................................... 7 8 8 10 11 12 12 12 13 13 14 15 15 15 RESULTS AND DISCUSSION ................................................................................................. 17 D e s c r i p t i o n ................. Biomass and P r o d u c t i v i t y .................................................................................. Biomass ............................................................................................................. P r o d u c t i v i t y .................................................................................................. S u c c e s s i o n ................................................................................................................. Tree d i a m e t e r , h e i g h t and age d i s t r i b u t i o n .............................. Canopy gap d e s c r i p t i o n ........................................................................... S e e d l i n g d e s c r i p t i o n , age and s i z e d i s t r i b u t i o n S u r v i v o r s h i p ................................................................................................. Environmenal p a r a m e t e r s ......................................................................... Deer b r o w s i n g ............................................................................................... White p i n e r e g e n e r a t i o n ......................................................................... S u c c e s s i o n and Biomass Model ......................................................................... 17 29 29 33 38 38 39 41 52 55 59 61 67 SUMMARY AND CONCLUSIONS ............................................................................................... 72 FOR FURTHER STUDY............................................................................................................... 75 LITERATURE CITED ............................................................................................................... 76 v LIST OF TABLES Table Page 1 Tree s p e c i e s a s s o c i a t e d w it h o l d growth w h it e pin e in n o r t h e a s t e r n North America.......................................................................... 19 2 L i n e a r r e g r e s s i o n s and c o e f f i c i e n t s o f c o r r e l a t i o n s with 95% c o n f i d e n c e l i m i t s f o r a l l o m e t r i c r e l a t i o n s h i p s developed from t h e s t u d y o f Hartwick Pines V i r g i n f o r e s t . . . . 22 3 Importance v a l u e s 3 ( I . V . ) f o r t r e e s p e c i e s ( > 1 . 5 m in h e i g h t ) i n t h e v i r g i n f o r e s t o f Hartwick S t a t e Pines P a r k ............................................................ 24 4 Age d i s t r i b u t i o n ( a s % o f s p e c i e s t o t a l ) and a v e r a g e age ( ± 1 S . D . ) o f t h e f i v e t r e e s p e c i e s ( > 1 . 5 m t a l l ) found a t H a r t w i c k .............................................................................................. 28 5 Estimate d biomass o f s t a n d i n g t r e e s ( > 1 . 5 m t a l l ) ..................... 30 6 Mean biomass and n e t pr im ary p r o d u c t i o n f o r ma jor f o r e s t ty p e s o f t h e w o r l d ............................................................................................ 31 7 Net prim ary p r o d u c t i v i t y ( k g / h a / y r ) o f t h e s i x t r e e s p e c i e s ( > 1 . 5 m t a l l ) in t h e v i r g i n Pinus s t r o b u s L. f o r e s t ....................................................................................................................... 34 8 Comparison o f t h e number o f t r e e s t h a t d i e d , c r e a t i n g t h e 21 gap f o r m a t i o n s , w it h t h e r e l a t i v e d e n s i t y o f t h e l i v i n g t r e e s ......................................................................................................... 40 9 The a g e , s i z e , and number o f dead t r e e s a s s o c i a t e d w ith each o f t h e i n t e n s i v e l y s t u d i e d gaps and t h e mean v a lu es f o r a l l g a p s ......................................................................................................... 43 10 Importance v a l u e s 3 ( I . V . ) f o r t h e woody s e e d l i n g s ( > 1 . 5 m in h e i g h t ) found i n t h e gaps and c l o s e d f o r e s t 44 11 P e r c e n t s u r v i v o r s h i p o f d i f f e r e n t aged s e e d l i n g s combined o ve r one y e a r ( f a l l , 1977, t o f a l l , 1978) in r e l a t i o n to season and b ro w s in g .......................................................................................... 54 12 S t u d e n t ' s t - t e s t comparison o f t h e e f f e c t o f d e e r browsing ove r one y e a r on t h e h e i g h t , crown c o v e r and sh oo t growth o f Acer saccharum and Acer rubrum combined vi 60 Page Table 13 Mean ( ± 2 S. D .) a g e , h e i g h t , crown c o v e r , and basal d i a m e t e r o f woody s p e c i e s found in t h e v i r g i n Pinus b an ksi an a Lamb, s t a n d ........................................................................................ 62 14 Importance v a l u e s ( I . V . ) f o r t r e e s p e c i e s in a 2 h e c t a r e Pinus s t r o b u s L. s t a n d in Mani st ee C o. , M ic h i g an ........................................................................................................... v ii 65 LIST OF FIGURES Fi gure Page 1 L o c a ti o n o f t h e s t u d y a r e a w i t h i n t h e v i r g i n w hit e p i n e f o r e s t a t Ha rtwick P in e s S t a t e P a r k ......................... . ................ 18 2 P r o f i l e diagram o f t h e v i r g i n w hi te pine f o r e s t a t Hartwick P in e s S t a t e P a rk . This diagram r e p r e s e n t s a s t r i p 7 .6 m x 60 m th r o u g h a 6 3 - y e a r - o l d gap e x t e n d i n g from t h e 27 t o 33 meter mark. Legend: PS=Pinus s t r o b u s , PR=Pinus r e s i n o s a , TO T s u g a c a n a d e n s i s , AR=Acer rubrum, AS=Acer saccharum, FG=Fagus g r a n d i f o l i a , DPS=Dead Pinus s t r o b u s , DA=Dead Acer s p p . , S=Stump, L=Log........................................................... 21 3 D i s t r i b u t i o n o f t r e e d i a m e t e r by s p e c i e s . (mean ±2 S . D . ) ....................................................................................................... 25 4 D i s t r i b u t i o n o f t r e e h e i g h t by s p e c i e s . (mean +2 S . D . ) ....................................................................................................... 26 5 C o n if e r o u s and de c id u o u s l e a f l i t t e r f a l l by month........................ 37 6 L o c a t i o n and s i z e o f s t r u c t u r a l ( - ) and f u n c t i o n a l ( - - ) gaps w i t h i n t h e sample a r e a . The path i n c l u d e s t h e a r e a w i t h i n t h e f o r e s t e l i m i n a t e d from t h e s t u d y t o re duce t h e edge e f f e c t ................................................................................ 42 7 Average s e e d l i n g crown c o v e r and sho ot gro w th, and p e r c e n t a g e o f browsed s e e d l i n g s in t h e gaps and f o r e s t . Legend: AS=Acer sa c c har um , AR=Acer rubrum, PS=Pinus s t r o b u s ............................................................................. 46 8 Six s e e d l i n g p a r a m e t e r s measured in gaps o f d i f f e r e n t a g e s , s u g g e s t i n g tempo ral chan ge s. The mean v a l u e s f o r s e e d l i n g s under t h e f o r e s t canopy a r e a l s o giv e n . Legend: AS=Acer s ac c h ar u m , AR=Acer ru bru m, PS=Pinus s t r o b u s , % Browse = P e r c e n t a g e of S e e d l i n g s Browsed................................................................... 47 9 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m in h e i g h t ) o f t h e t h r e e ma jor s p e c i e s found i n 5 - y e a r - o l d g a p s .................................... 49 10 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1 .5 m in h e i g h t ) o f t h e t h r e e major s p e c i e s found in a 33- and 3 7 - y e a r - o l d g a p ................................................................................................................................ 49 vi i i F ig u re Page 11 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m in h e i g h t ) o f t h e t h r e e major s p e c i e s found i n a 5 0 - y e a r - o l d ga p.............................. 50 12 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1 .5 m in h e i g h t ) o f t h e t h r e e m aj or s p e c i e s found in a 6 3 - y e a r - o l d gap........................................... 50 13 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m in h e i g h t ) o f t h e t h r e e m a jo r s p e c i e s found in a 9 0 - y e a r - o l d gap ............................................ 51 14 D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1 .5 m in h e i g h t ) and DBH ( i n d i v i d u a l s > 1 . 5 m in h e i g h t ) o f t h e t h r e e ma jor s p e c i e s found in 1 0 0 - y e a r - o l d gap.............................................. 51 15 A ir t e m p e r a t u r e i n t h e t h r e e a r e a s d u r i n g two days in t h e s p r i n g and two days in t h e summer. Legend: Pin e Reg en e ra tio n=o pe n a r e a where w h i t e p i n e a r e regenerating. Gap=area under t h e gap in t h e canopy, F o r e s t = a r e a un de r t h e f o r e s t c an op y....................................................... 56 16 R e l a t i v e h u m id it y in t h e t h r e e a r e a s d u r i n g two days in t h e s p r i n g and two days in t h e summer. Legend: Pin e R eg e n e ra ti o n = o p e n a r e a where w h it e p i n e a r e r e g e n e r a t i n g , Gap=area under t h e gap in t h e canopy, F o r e s t = a r e a un de r t h e f o r e s t canopy ............................ 57 17 Age d i s t r i b u t i o n o f Pinus b a n k s i a n a and Pinus s t r o b u s i n a v i r g i n Pinus b a n k s i a n a s t a n d ............................................ 63 18 D i s t r i b u t i o n o f t r e e d i a m e t e r and h e i g h t by s p e c i e s i n t h e v i r g i n s t a n d n e a r D u b l i n , Michi gan ......................................... 64 19 H y p o t h e t i c a l s e r a i s t a g e s i n an a r e a o f c e n t r a l n o r t h e r n lower Michigan i n d i c a t i n g changes in biomass and t h e i n f l u e n c e o f d i s t u r b a n c e ............................................ 68 ix INTRODUCTION From 1840-1900 Michigan l e d t h e n a t i o n in lumber p r o d u c t i o n , w h i t e p i n e ( Pinus s t r o b u s L . ) a c c o u n t i n g f o r t h e m a j o r i t y of t i m b e r h a r v e s t e d . By t h e end o f t h i s e r a i t was e s t i m a t e d t h a t 160 b i l l i o n board f e e t of p i n e had been c u t (Maybee 1 9 6 0 ), w ith as much as an a d d i t i o n a l 160 b i l l i o n board f e e t l o s t t o f i r e (F rot hin gha m 1914 ). P r i o r t o 1840, t h e dominant f o r e s t o f t h e upper p e n i n s u l a and t h e n o r t h e r n h a l f of t h e lower p e n i n s u l a o f Michigan c o n s i s t e d o f pure and mixed s t a n d s o f w h it e p i n e , re d pine ( Pinus r e s i n o s a ) , j a c k p in e ( Pinus b a n k s i a n a ) , and hardwoods. The s o u t h e r n l i m i t of w h i t e p i n e lum be rin g e xt en de d a c r o s s t h e s t a t e from VanBuren County in t h e w e s t , n o r t h e a s t t o G r a t i o t County and e a s t t o S t . C l a i r e County (Wheeler 1898). White p i n e ' s abundance and u t i l i t y was an im p o r t a n t f a c t o r in t h e development of Michigan. However, by 1914 v i r t u a l l y a l l l a r g e t r e e s had been e l i m i n a t e d and t o d a y onl y a few small v i r g i n t r a c t s , t h o s e t h a t are r e l a t i v e l y u n d i s t u r b e d and have m a i n t a i n e d a p r e s e t t l e m e n t c h a r a c t e r , remain. The only s t a n d in t h e lower p e n i n s u l a l a r g e r t h a n f i f t y a c r e s i s l o c a t e d a t I n t e r l o c h e n S t a t e Park ( C o l l i n s 195 8), an open s t a n d of w h i t e pin e mixed w ith hardwoods ( K i t t r e d g e and C h i t t e n d e n 1929). A n o th e r, s m a l l e r , v i r g i n s t a n d where w h i t e p in e c l e a r l y dominates i s found a t Hartwick P in e s S t a t e P a rk . Hartwick P i n e s i s in Crawford County about 7 m i l e s n o r t h e a s t of G r a y l i n g , Michigan. The a r e a i n and around Crawford County i s a p in e 1 2 b a r r e n s o r p l a i n s dominated by j a c k p i n e . This i s t h e c e n t e r o f t h e n o r t h e r n h ig h l a n d s o f M ic h i g a n ' s lower p e n i n s u l a (Veatch e t a l . 1927). High r o l l i n g h i l l s produced by g l a c i e r s o v e rl ook t h e v i r g i n w h it e pin e s t a n d a t H a r t w i c k , which o c c u p ie s a low sandy r i d g e and p a r t of a f l a t sandy p l a i n . S e v e ra l f a c t o r s , documented in t h e l i t e r a t u r e , have been shown t o i n f l u e n c e t h e p r e s e n c e o f w hi te p in e and a s s o c i a t e d t r e e s p e c i e s . l i t t e r l a y e r a f f e c t s w h it e p in e g e r m i n a t i o n and s u r v i v a l 1914, Ahlgren 1976). The (Frothingham Although t h e y can g e r m in a te and grow in a l i t t e r l a y e r or b a r e mine ral s o i l w it h an a d e q u a te m o i s t u r e s u pp ly (Maissurow 1935), q u i t e o f t e n t h e l i t t e r becomes t o o dry f o r s e e d l i n g s u r v i v a l (Smith 1940, Graham 1 9 41). White pi ne a r e o f t e n outcompeted by hardwoods on b e t t e r s o i l s and a r e u s u a l l y r e l e g a t e d t o sandy s o i l s (F rothingham 1914). For example, many of M ic h i g a n ' s e a r l y w h it e p in e f o r e s t s , i n c l u d i n g Hartwick P i n e s , grew on m ois t sandy s o i l 1968). (Harlow and H a r r a r G e n e r a l l y , sandy s o i l s t h r o u g h o u t t h e s t a t e s u p p o r t e d m i x t u r e s of w h i t e p i n e , red p i n e , hemlock ( Tsuga c a n a d e n s i s ) , balsam f i r ( Abies b a l s a m e a ) and hardwoods. ( Quercus s p p . ) dom in a te d. On d r i e r s i t e s , re d p i n e , j a c k pine o r oak F i n e r t e x t u r e d s o i l s g e n e r a l l y le d t o t h e development of hardwood s t a n d s . O u t s i d e o f Michigan on b e t t e r s o i l s , hemlock, red s p r u c e ( P i c e a r u b e n s ) , s u g a r maple ( Acer sa c c ha ru m ) , beech (Fagus g r a n d i f o l i a ) , basswood ( T i 1i a a m e r i c a n a ) , elm (Ulmus a m e r i c a n a ) and y e l l o w b i r c h ( B e t u la l u t e a ) a s s o c i a t e w it h w h i t e p i n e , w h il e red p i n e , j a c k p i n e , p i t c h p in e ( Pinus r i g i d a ) , oak and c h e s t n u t ( C as ta nea d e n t a t a ) were a s s o c i a t e s o f w h i t e p in e on dry sandy s o i l . I t was e s t i m a t e d t h a t in M ic h i g a n ' s Upper P e n i n s u l a a l o n e , p r i o r t o lu m b e ri n g , t h e r e were 1 .6 m i l l i o n a c r e s o f w hi te p i n e (Cunningham and 3 White 1941). By 1896-97 t h e t o t a l re m a in in g w h i t e pin e a c r e a g e in Michigan had been reduc ed t o 775, 20 8, w i t h 13,000 in Crawford County (Wheeler 1898). When Hartwick P i n e s Park was given t o t h e S t a t e of Michigan i n 1927, i t c o n t a i n e d t h e l a s t known 85 a c r e s o f pure v i r g i n w h it e pin e in t h e lower p e n i n s u l a . Wackerman (1924) e s t i m a t e d t h e board f o o t a g e o f t h e s t a n d a t 2 , 5 8 9 , 0 0 0 , with w h it e p i n e c o m p r i s i n g 1 , 6 9 1 ,0 0 0 board f e e t . There a r e s e v e r a l e x p l a n a t i o n s f o r why Hartwick P i n e s was not lumbered. H a n se n 's lum be rin g o p e r a t i o n i n G r a y l i n g o r i g i n a l l y owned t h e p r o p e r t y in t h i s a r e a and had c u t t h e b e s t t i m b e r t o t h e p r e s e n t v i r g i n f o r e s t boundary. C u t t i n g sto pped be ca us e many o f t h e w h it e p i n e s had a lower v a lu e s a l m o n - p i n k - c o l o r wood, s i m i l a r t o t h e ol d growth t i m b e r in New Hampshire d e s c r i b e d by Baldwin ( 1 951) . Co nc u rr en t w ith t h i s was t h e economic pa n ic of 1893 when lumber o r d e r s dropped d r a m a t i c a l l y (Maybee 1960). A f t e r r e c o v e r i n g from t h e 1893 p a n i c , lumber o p e r a t i o n s began t o f i r s t c u t t h e re m a in in g few l a r g e v i r g i n pi n e t r a c t s and l a t e r used t r e e s from t h e edge o f Ha rtwick Pi ne s as a s o u r c e f o r s p e c i a l o r d e r s . At t h i s t i m e t i m b e r v a l u e had gone up but a new t a x ass e ss m e nt made i t more economical t o s e l l t h e p r o p e r t y . Karen B. Hartwick t h e n purc ha sed t h e s t a n d and gave i t t o t h e s t a t e as a l i v i n g memorial t o h e r husband, a lumber b a r o n . A wind s to rm in t h e 1940' s reduc ed t h e t r a c t from 85 t o 49 a c r e s , p o s s i b l y a id e d by a roa d t h ro u g h t h e f o r e s t t h a t hampered n a t u r a l s o i l d r a i n a g e , weakening r o o t s and s o i l s t r u c t u r e and e x p o s in g t h e t r e e s t o t h e f u l l f o r c e o f t h e wind. f o r e s t in a n o t h e r way. Human impact on Hartwick has i n f l u e n c e d t h e During t h e tim e of t h e C i v i l i a n C o n s e r v a t i o n Corps a d e c i s i o n was made t o " c l e a n up" t h e v i r g i n f o r e s t by removing 4 some downed t r e e s and small maples. Even w ith t h i s i n f l u e n c e , Hartwick Pine s remains one o f t h e few examples o f a w hi te p in e dominated v i r g i n forest. The economic im por ta nc e of w h it e pi ne s t i m u l a t e d r e s e a r c h and in v e n to rie s in th e e a r l y 1900's. At t h a t t i m e , r e s e a r c h c e n t e r e d on management and p r o d u c t i o n o f w hit e pin e f o r t i m b e r p r o d u c ts (Froth ing ha m 1914, Cunningham and White 1941, C lin e and S p u r r 1942). S e v e ra l s t u d i e s c o n c e rn e d w h i t e p in e e c o lo g y and s u c c e s s i o n a l s t a t u s (Grant 1934, K i t t r e d g e 1934, Morey 1936). More r e c e n t l y t h e volume o f l i t e r a t u r e , p a r t i c u l a r l y e c o l o g i c a l s t u d i e s of n a t u r a l s t a n d s , has d e c l i n e d , p r o b a b l y due t o a d e c r e a s e in t h e im port an ce o f t h e s e s t a n d s f o r t i m b e r p r o d u c t i o n and t h e l i m i t e d p o t e n t i a l o f w hi te p in e because o f i n s e c t and d i s e a s e problems (Harlow and H a r r a r 1968). Some o f t h e more r e c e n t s t u d i e s c once rn growth, r o o t g r a f t i n g (Bormann and Graham 1959, Bormann 1965) and r e g e n e r a t i o n a f t e r f i r e (Ahlgren 1976, B a r r e t t e t a l . 1976 ). But t h e r e i s a s u r p r i s i n g lack o f i n f o r m a t i o n a bout t h e s t r u c t u r e and f u n c t i o n , s p e c i f i c i a l l y t h e s t a n d i n g biomass and prim ary p r o d u c t i v i t y , o f l a r g e o ld grov/th s t a n d s such as H a rt w ic k . Biomass and p r o d u c t i v i t y a r e o f t e n d i f f i c u l t t o m e asu re , and d e s t r u c t i v e sampling i s e i t h e r p r o h i b i t e d , o r p h y s i c a l l y d i f f i c u l t (Denison e t a l . 1972). A ls o , emphasis in p a s t s t u d i e s has been on e c o n o m i c a l l y i m p o r t a n t f o r e s t s , which i n c l u d e p l a n t a t i o n s and f o r e s t s composed o f youn ge r and sm aller t r e e s . Of t h e 291 biomass and p r o d u c t i v i t y s t u d i e s r e p o r t e d by Art and Marks ( 1 9 7 1 ) , 3 5 . 4 p e r c e n t were o f p l a n t a t i o n s with an av er ag e age o f 29 y e a r s (S.D. = 2 6 . 7 ) . was 4 5 . 8 y e a r s (S.D. = 3 4 . 0 ) . The a v e r a g e age o f t h e n a t u r a l stands 5 T h e o r e t i c a l a s p e c t s o f p r o d u c t i v i t y have been d i s c u s s e d in t h e p a s t and r e l a t e t h e need f o r more r e s e a r c h c o n c e r n i n g p r o d u c t i o n (Lindeman 1942, Macfadyn 1948, Odum 1971 ). Primar y p r o d u c t i v i t y o f a system can be used as an i n d i c a t o r o f f u n c t i o n a l c a p a c i t y . Not o n ly i s i t an i n d i c a t i o n of t h e n a t u r a l e n v i r o n m e n t ' s a b i l i t y t o s u p p o r t l i f e , but i t a l s o l e a d s t o a b e t t e r u n d e r s t a n d i n g o f p o t e n t i a l human imp ac t. H e t e r o t r o p h i c organisms acc ou nt f o r only 0.1% o f t h e l i v i n g m a t t e r in t h e b i o s p h e r e (Rodin and B a z i l e v i c h 19 68) ; t h e r e f o r e , biomass and p r o d u c t i v i t y s t u d i e s o f green p l a n t s can l e a d t o r a t i o n a l use o r non -use o f most l i v i n g m a t t e r . The energy c r i s i s has s t i m u l a t e d i n t e r e s t in use of biomass as an energy s o u rc e . The most i m p o r t a n t i s s u e d u r i n g an i n t e r n a t i o n a l Man and t h e B i o s p h e r e workshop in 1979 on r a t i o n a l f o r e s t u t i l i z a t i o n was t h e use o f f o r e s t s as a s o u r c e o f f u e l (Boyce 19 79 ). I t was recommended t h a t each c o u n t r y a s s e s s f o r e s t p r o d u c t i v i t y and p o t e n t i a l f o r use as an energy source. The e a r l y l i t e r a t u r e d e a l i n g w it h t h e q u e s t i o n o f wh e th er e a s t e r n w h i t e p i n e i s a p a r t o f t h e climax f o r e s t is c o n t r a d i c t o r y . Based on a v a i l a b l e l i t e r a t u r e , D e t w i l e r (1933) p u t f o r t h a c a s e in s u p p o r t of w h i t e p i n e as a member o f t h e cl im a x f o r e s t , bu t Hawley (1933) q u e s t i o n e d t h i s view and c i t e d t h e same l i t e r a t u r e (Fernow 1899, W hit for d 1901, S t a l l o r d 1929) t o show t h a t w h it e p i n e i s not a c li m a x s p e c i e s . Graham (1941) a t t e m p t e d t o s e t t l e t h e i s s u e by d e f i n i n g a climax f o r e s t as ha v in g t h e a b i l i t y t o r e p r o d u c e i t s e l f g e n e r a t i o n a f t e r g e n e r a t i o n . He co n c lu d e d t h a t w h it e p in e does not q u a l i f y b eca us e i t l a c k s a high d e g r e e o f shade t o l e r a n c e and t h e a b i l i t y t o r e p r o d u c e in a deep l i t t e r layer. O b j e c t i v e l i t e r a t u r e re vie w and f i e l d o b s e r v a t i o n r e i n f o r c e t h i s 6 conclusion. Even with t h i s a p p a r e n t c o n t r o v e r s y r e s o l v e d , t h e r e i s a l a c k o f i n f o r m a t i o n on t h e dynamics of w h i t e p i n e ' s s u c c e s s i o n a l r o l e . Climax and s u c c e s s i o n have been major p o i n t s of s tu d y and c o n t r o v e r s y among e c o l o g i s t s . Various methods have been used t o i d e n t i f y a clim ax system (Cooper 1913, 1923, Weaver and Clements 1938, Braun 1950, W h i t t a k e r 1953, 1974, Shimwell 1971). As W h i t t a k e r (1974) has p o i n t e d out t h e community p o p u l a t i o n s t r u c t u r e s h ou ld be c o n s i d e r e d in o r d e r t o u n d e r s t a n d s u c c e s s i o n , clima x and t h e way in which s p e c i e s p e r p e t u a t e themselves. In a d d i t i o n , t h e s u c c e s s i o n a l t r e n d s p r e s e n t e d by Odum (1969) o f i n c r e a s i n g biomass and s t a t u r e s h ou ld be t e s t e d . Thi s r e s e a r c h p r o j e c t i n v e s t i g a t e d prim ary p r o d u c t i o n and s u c c e s s i o n a l s t a t u s o f a v i r g i n w h i t e p i n e f o r e s t a t Hartwick Pi ne s S t a t e Park. The s p e c i f i c o b j e c t i v e s were: 1. t o d e s c r i b e t h e s t r u c t u r e and taxonomic c o m p o s i ti o n o f t h e woody populations; 2. t o e s t i m a t e t h e biomass and net prim ary p r o d u c t i o n of t h e p o p u l a t i o n s o f t r e e s i n t h e w h it e p in e community, 3. t o d e t e r m i n e t h e s u c c e s s i o n a l dynamics o f t h e w h i t e p in e community by s t u d y i n g f o r e s t canopy gaps and by u s i n g t h e age o f t r e e s , s t r u c t u r a l c o n s i d e r a t i o n s , and s e e d l i n g s u r v i v o r s h i p ; and 4. t o de vel op a s u c c e s s i o n a l model f o r t h i s a r e a chang es in biomass. and r e l a t e i t to METHODS AND MATERIALS Co mmu nit y.D esc rip ti on The e x p e r im e n t a l a r e a was marked o f f by s t a k e s e ver y 20 m forming a 220 m x 160 m sample g r i d . o u t e r margin of w hi te p i n e . Sampling was a void ed n e a r t r a i l s and t h e Twenty randomly s e l e c t e d c i r c u l a r p l o t s , each 200 s q u a r e m e t e r s in a r e a , were used t o d e s c r i b e woody p l a n t s 1.5 m e te rs o r more in h e i g h t . Measurements in c lu d e d d i a m e t e r a t b r e a s t h e i g h t (DBH, 1 .5 m), t o t a l h e i g h t , h e i g h t t o t h e bottom o f t h e crown, and N-S and E-W crown d i a m e t e r . Imp ortance v a lu e s were c a l c u l a t e d f o r a l l t r e e s p e c i e s (Mueller-Dombois and E l l e n b e r g 1974). Crown h e i g h t and crown d i a m e t e r were used t o e s t i m a t e p h o t o s y n t h e t i c a r e a f o r c o r r e l a t i o n w it h t r e e grow th. I d e n t i c a l measurements were t a k e n o f a l l t r e e s a lon g an Ea st -W est t r a n s e c t ( 7 . 6 x 60 m) which was l o c a t e d t o i n c l u d e a gap in t h e f o r e s t canopy produced by a f a l l e n t r e e . Inc rement c o r e s of randomly s e l e c t e d t r e e s were t a k e n in 1978 from 24 w h i t e p i n e , 10 hemlock, and 6 each o f red p i n e , s u g a r ma ple, red maple (Acer rubrum) and b e ec h, and p r o c e s s e d f o l l o w i n g t h e methods o f Stokes and Smiley ( 1 9 6 8 ) . These c o r e s were used t o d e t e r m i n e t r e e a g e s , from which a l i n e a r r e g r e s s i o n r e l a t i o n s h i p was e s t a b l i s h e d between d ia m e te r and ag e. Because t h e in c re m en t b o r e r d i d not re a ch t h e c e n t e r o f t h e l a r g e s t t r e e s , e s t i m a t e s o f t h e number o f unsampled y e a r s were made by d i v i d i n g t h e rema in in g d i s t a n c e by t h e a v e r a g e annual in c re m en t of t h e f i v e y e a r s sampled n e a r e s t t h e c e n t e r . 7 Two c o r e s were a l s o t a k e n from 8 each of two t r e e s t h a t were f i r e s c a r r e d t o d e t e r m i n e t h e d a t e of t h e most r e c e n t f i r e . To e s t a b l i s h t h e e x t e n t t o which Hartwick P i n e s re sem ble s t h e v i r g i n p i n e f o r e s t t h a t once c ov er ed p a r t s of n o r t h e r n Michigan, a comparison of t r e e d e n s i t y (number of t r e e s p e r u n i t a r e a ) and mean stump d i a m e t e r (60 cm above t h e ground) was made with a p i n e stump f i e l d two m i l e s n o r t h o f Hartwick P i n e s . F i f t e e n randomly s e l e c t e d c i r c u l a r p l o t s , each 200 m2, were used t o o b t a i n stump d i a m e t e r measurements and d e n s i t y . A r e g r e s s i o n e q u a t i o n was develop ed between stump d i a m e t e r and DBH f o r l i v i n g t r e e s a t Hartwick P i n e s f o r a p p l i c a t i o n t o t h e stump f i e l d . P r o c e d u re s d e s c r i b e d by Parde (1968) were used t o e s t i m a t e t r e e volumes from stump measurements. The v i r g i n w h it e p i n e a r e a t h a t was d e s t r o y e d by a st orm in t h e 1 9 4 0 ' s was a l s o d e s c r i b e d from f i f t e e n randomly s e l e c t e d 100 m2 c irc u la r plots. Impor tanc e v a l u e s were c a l c u l a t e d from measurements o f t r e e s g r e a t e r t h a n 1 .5 m t a l l . This i n f o r m a t i o n was used t o de te rm in e changes in t h e f o r e s t as a r e s u l t of t h e sto rm . Biomass and P r o d u c t i v i t y D e s t r u c t i v e sam pl ing of v e g e t a t i o n was p r o h i b i t e d by t h e Michigan Department o f N a tu ra l R e s o u r c e s . Methods p r e s e n t e d h e r e were de ve lo pe d w ith t h i s c o n s t r a i n t in mind. Stem. A l l o m e t r i c t e c h n i q u e s were used t o de vel op an e q u a t i o n t o c a l c u l a t e w h i t e p i n e stem volume (Newbould 1 9 6 7 ). The e q u a t i o n was o b t a i n e d by u s i n g a c c u r a t e l y e s t i m a t e d volumes o f f a l l e n t r e e s , c a l c u l a t e d from d i a m e t e r s t h a t were measured e v e r y m e te r f o r t h e f u l l l e n g t h of t h e f a l l e n t r e e s (T a b le 2 ) . T o t al stem wood volume was e s t i m a t e d from t h e DBH minus bark t h i c k n e s s u s i n g t h i s e q u a t i o n . Bark 9 t h i c k n e s s was c a l c u l a t e d u s in g a r e g r e s s i o n e q u a t i o n de vel ope d f o r t h i s s t a n d (T a b le 2 ) . Bark volume i s t h e d i f f e r e n c e between stem volume i n c l u d i n g bark and wood volume c a l c u l a t e d u s i n g DBH w i t h o u t b a r k ; t o acc o u n t f o r bark t a p e r and r i d g e s , t h i s va lu e was m u l t i p l i e d by 0 . 5 , a c o n s e r v a t i v e f i g u r e t h a t p r oba bl y l e d t o s l i g h t u n d e r e s t i m a t e s in bark volume. Seventy p e r c e n t o f t h e c r o s s s e c t i o n a l a r e a between t h e wood and t h e p e r i m e t e r e s t a b l i s h e d by t h e t i p of each bark r i d g e was a c t u a l l y b a r k . Wood d e n s i t y and bark d e n s i t y were d e te r m in e d from sample c o r e s and used f o r c o n v e r t i n g volumes t o dry w e i g h t s . Stem p r o d u c t i v i t y was e s t i m a t e d in p a r t by f o l l o w i n g methods o u t l i n e d by Newbould (1967) and W h i t t a k e r and Marks ( 1 97 5) . Average p r o d u c t i o n of w h i t e p in e stem wood was c a l c u l a t e d in t h e f o l l o w i n g manner u s i n g t h e e q u a t i o n de ve lo pe d i n t h i s s t u d y r e l a t i n g DBH and volume. t a k e n in 1978 from t r e e s o f a l l Using c o re s s i z e c l a s s e s , a v er ag e annual r a d i a l i n c r e ­ ment f o r t h e f i v e y e a r s p r e c e d i n g t h e s t u d y was d e t e r m i n e d . Annual volume in c re m en t was c a l c u l a t e d by f i n d i n g t h e d i f f e r e n c e between t h e volume p r e d i c t e d from t h e most r e c e n t DBH and t h e volume p r e d i c t e d from t h e DBH a f t e r s u b t r a c ti n g th e average ra d ia l increment. The a v e r a g e volume i n c r e ­ ment was c o n v e r t e d t o dry weight u s i n g wood d e n s i t y , a l l o w i n g an e s t i m a t e t o be made o f a v e r a g e annual stem wood p r o d u c t i o n . Once t h e annual growth in c re m en t had been d e te r m in e d f o r a l l s i z e c l a s s e s , a r e g r e s s i o n e q u a t i o n was e s t a b l i s h e d r e l a t i n g volume and biomass incre men t t o DBH. Stem biomass and p r o d u c t i o n o f t h e o t h e r f i v e s p e c i e s in t h e s t a n d were e s t i m a t e d u s i n g e q u a t i o n s from Newbould (196 7) . An a p p r o x im a ti o n of volume was o b t a i n e d u s i n g t h e e q u a t i o n f o r a p a r a b o l o i d o f r o t a t i o n s : Vp . h S l where r i s t h e r a d i u s a t b r e a s t h e i g h t and h i s t h e t r e e h e i g h t . The 10 c a l c u l a t i o n was com ple ted f o r each of t h e 5 s p e c i e s and m u l t i p l i e d by t h e d e n s i t y of t h e i r wood give n by Brown e t a l . e s t i m a t e of biom ass. (19 49 ), r e s u l t i n g in an The ba sa l a r e a in crem ent was c a l c u l a t e d from Ai = » [ ( r 2 - ( r - 1 ) 2 ) ] where i i s t h e a v e r a g e annual r a d i a l in c re m en t based on t h e l a s t f i v e y e a r s and r t h e r a d i u s a t b r e a s t h e i g h t . Using b a sa l a r e a in c re m en t (A) and h e i g h t (h) an e s t i m a t e of t h e stem wood volume in c re m en t was computed from Vi = 1/2 (Ai x h ) . Volume in c re m e n t was t h e n c o n v e r t e d t o biomass in c re m en t by m u l t i p l y i n g by wood d e n s i t y . Branch. I t i s commonly assumed t h a t mature e cos ys tem s a r e in e n e r g e t i c s t e a d y s t a t e and t h a t ne t annual pri m ar y p r o d u c t i o n i s equal t o annual l i t t e r p r o d u c t i o n (Kimura 1960, c i t e d by Newbould 1967, Nye 1961, Kira and S h i d e i 1967, Odum 1971). Bray and Gorham (1964) m a i n t a i n t h a t l i t t e r f a l l measurement m ig h t, t h e r e f o r e , be used as an e a s i l y o b t a i n e d e s t i m a t o r of ne t p r o d u c t i o n . methods f o r such an a n a l y s i s . Newbould (1967) p r e s e n t s a p p r o p r i a t e Fo ll ow in g t h e s e a s s u m p t i o n s , branc h p r o d u c t i o n was e s t i m a t e d by meas uri ng branch l i t t e r f a l l from l a t e summer 1975 t o l a t e f a l l 1978. F i f t e e n l i t t e r t r a p s , each one s q u a r e m e te r in a r e a , were randomly p l a c e d w i t h i n t h e samp li ng g r i d and used t o measure t h e a c c u m u l a t i o n r a t e of branch l i t t e r l e s s t h a n one c e n t i m e t e r in d i a m e t e r . The p l o t s were c i r c u l a r and b o r d e r e d by a metal s t r i p t o p r e v e n t l a t e r a l movement o f l i t t e r i n t o and out o f t h e sample p l o t s . T r a n s e c t p l o t s , two m e te rs wide and a t o t a l o f 650 m e te rs lo n g , were e s t a b l i s h e d t o sample branch l i t t e r l a r g e r t h a n one c e n t i m e t e r in d i a m e t e r . I n i t i a l l y , a l l b ra n c h e s were 11 removed from t h e sample p l o t s . c o l l e c t e d and weighed. dry w e i g h t . Each s p r i n g and f a l l a l l b r a n c hes were In both c a s e s , subsamples were used t o d e t e r m i n e As i t was not p o s s i b l e t o s o r t bra nc he s by s p e c i e s , d a t a were c l a s s i f i e d as branc h l i t t e r f a l l combined. (b r an c h p r o d u c t i o n ) f o r a l l species Branch biomass and p r o d u c t i o n were assumed t o be p r o p o r t i o n a l t o t h e stem biomass and p r o d u c t i o n f o r each s p e c i e s . An e s t i m a t e of each s p e c i e s ' bra nc h p r o d u c t i o n was o b t a i n e d by m u l t i p l y i n g i t s p e r c e n t a g e of t o t a l stem p r o d u c t i o n by t o t a l branch p r o d u c t i o n . Branch biomass was d e t e r m i n e d from t h e r a t i o B/b = S / s where B = s p e c i e s branch biom as s, b = s p e c i e s branch p r o d u c t i o n , S = s p e c i e s stem bio m a s s, s = s p e c i e s stem p r o d u c t i o n ( W h i t t a k e r 1965, W h i t t a k e r and Marks 197 5). Foliage. Using t h e one m e te r s q u a r e branch l i t t e r p l o t s , l e a f l i t t e r f a l l was measured from l a t e summer 1975 t o l a t e f a l l 1978 t o estim ate le a f production. L i t t e r f a l l was measured once a month f o r a y e a r to e s t a b l i s h seasonal v a r ia tio n . F i f t e e n e l e v a t e d l i t t e r t r a p s were used t o c a t c h f a l l i n g l i t t e r w h i l e snow c ov er ed t h e gro un d. The t r a p s c o n s i s t e d of a c l o t h and p l a s t i c sack suspended from a wooden frame . The wooden frame was 0 .2 5 m^ i n a r e a and was s u p p o r t e d by a s i n g l e metal pole. The m a j o r i t y o f p i n e l i t t e r f e l l i n Oc to be r and November, s i m i l a r t o t h e de ci duo us s p e c i e s , which a llo w ed sampling once in t h e s p r i n g and once in t h e f a l l . Samples were s o r t e d by s p e c i e s , d r i e d , and weighed. White and re d p i n e l e a f biomass was e s t i m a t e d by m u l t i p l y i n g t o t a l l e a f f a l l f o r one y e a r by t h e l i f e span o f a n e e d l e . The age o f t h e o l d e s t n e e d l e s , two y e a r s f o r w h i t e p i n e and f o u r y e a r s f o r r e d p i n e , was d e te r m in e d by o b s e r v i n g t h e n e e d l e ' s p o s i t i o n on t h e branch i n r e l a t i o n t o branch age a t t h a t p o i n t , and c o n fi rm e d by Harlow and H a r r a r (1968). Because w h i t e p i n e bud s c a l e s a r e produced and l o s t i n t h e same y e a r , t h e 12 e s t i m a t e of t h e i r annual l i t t e r p r o d u c t i o n was equal t o t h e i r biomass. The bud s c a l e biomass was i n c l u d e d in w h it e pi ne l e a f biom as s. Leaf biomass of deci duo us s p e c i e s was d i r e c t l y measured f o l l o w i n g l e a f drop in the f a l l . Ro ot . Root biomass and p r o d u c t i o n were e s t i m a t e d from d a t a f o r s i m i l a r f o r e s t s gi ve n in t h e l i t e r a t u r e (Young and C a r p e n t e r 1967, J o h n s t o n e 1971, Leaf 1 9 71 ). In most c a s e s r o o t biomass was given as 15-16% o f t h e t o t a l above ground bi om as s. Root p r o d u c t i v i t y was d e r i v e d from e q u a t i n g t h e p r o p o r t i o n o f stem biomass t o stem p r o d u c t i o n with t h e p r o p o r t i o n o f r o o t biomass t o r o o t p r o d u c t i v i t y . These methods a r e only rough a p p r o x i m a t i o n s , bu t t h e y a l l o w e s t i m a t i o n of t o t a l biomass and productivity. S u c c e s s io n Tree d i a m e t e r , h e i g h t and age d i s t r i b u t i o n . Inferences concerning s u c c e s s i o n were made by a n a l y z i n g s u r v i v a l w i t h i n t r e e p o p u l a t i o n s . s u r v i v a l a s p e c t s were c o n s i d e r e d : Two t h e a b i l i t y t o l i v e t o t h e nex t age c l a s s , and t h e a b i l i t y t o r e a c h r e p r o d u c t i v e m a t u r i t y . Forest analyses have used h e i g h t and d i a m e t e r d i s t r i b u t i o n s t o draw c o n c l u s i o n s about survival (Hough 1936, Meyer 1952, Hett and Loucks 1971). For example, a l a r g e r a t i o o f mature t o immature i n d i v i d u a l s of a p a r t i c u l a r s p e c i e s has o f t e n been i n t e r p r e t e d t o mean t h a t t h i s s p e c i e s i s f a i l i n g t o re p r o d u c e and i s not r e p l a c i n g i t s e l f (Braun 1950, Mueller-Dombois and E l l e n b u r g 1974). Even though t h i s may be an i n c o r r e c t assu mpt ion f o r some s p e c i e s , a d i s t r i b u t i o n a l diagram o f h e i g h t and d i a m e t e r was e s t a b l i s h e d f o r each s p e c i e s as one p o s s i b l e i n d i c a t o r o f s u r v i v a l . Als o, co mparisons o f age were made between s p e c i e s t o more a c c u r a t e l y de te r m in e s p e c i e s re g e n e ra tio n or replacement. 13 Canopy gap d e s c r i p t i o n . A d d i t i o n a l l y , a s tu dy of f o r e s t canopy gaps was used t o a s s e s s t h e s u c c e s s i o n a l s t a t u s of t h e community. Gaps of v a r i o u s s i z e s c o n t a i n i n g s a p l i n g s and s e e d l i n g s i n d i c a t e t h e f o r e s t is b e in g r e p l a c e d i n a gap phase f a s h i o n (Bray 1956). Skeen (1976) p o i n t e d o u t t h e s i g n i f i c a n c e o f s t u d y i n g n a t u r a l l y c r e a t e d open ings in d e t e r m i n i n g s e e d l i n g r e g e n e r a t i o n and s u r v i v a l . and mapped w i t h i n t h e sample a r e a . To t h i s en d, a l l gaps were l o c a t e d Each gap was c o n s i d e r e d t o c o n s i s t of a s t r u c t u r a l a r e a , t h e canopy a r e a l e f t open by t h e d e a t h o f a t r e e , and a f u n c t i o n a l a r e a , d e f i n e d by t h e o u t e r f o l i a g e p e r i m e t e r of t h o s e s p e c i e s t h a t a r e i n v a d i n g t h e a r e a a f f e c t e d by t h e opening in t h e canopy. The age of each gap was e s t i m a t e d in 1977 by c o r i n g t r e e s a t t h e p e r i m e t e r of t h e gap and d e t e r m i n i n g t h e y e a r o f t h e i r r e l e a s e from suppression. Hemlock was used in most c a s e s be cau se i t has been documented as an u n d e r s t o r y s p e c i e s t h a t p r o m i n e n tl y e x h i b i t s t h i s r e l e a s e from s u p p r e s s i o n (Graham 194 1). A f t e r a g in g t h e g a p s, e i g h t were s e l e c t e d , c o v e r i n g t h e f u l l range o f a g e s , and sampled t o i l l u s t r a t e what changes might o c c u r ov er ti m e in a r e l a t i v e l y s t a b l e f o r e s t . This a n a l y s i s a llo w ed f o r e s t i m a t i o n of t h e f o r e s t t u r n o v e r r a t e and gap occurrence frequency. S e e d l i n g d e s c r i p t i o n , age and s i z e d i s t r i b u t i o n . F o r e s t openings were t h e a r e a s o f most a c t i v e t u r n o v e r and t h e key t o t h e s u c c e s s i o n a l s t a t u s of t h i s f o r e s t . Age and s i z e d i s t r i b u t i o n s of a l l woody s p e c i e s found i n t h e gaps were, t h e r e f o r e , c o n s t r u c t e d t o p r o v i d e i n f o r m a t i o n on gap c o l o n i z e r s u r v i v o r s h i p . Four one m e te r s q u a r e p l o t s were e s t a b l i s h e d in each gap t o sample s e e d l i n g s . All woody i n d i v i d u a l s l e s s t h a n 1 . 5 m i n h e i g h t were t o be i n c l u d e d ; however, none were l a r g e r t h a n 100 cm. S e e d l i n g ages were r e c o r d e d in t h e f i e l d by c o u n ti n g t h e number of bud s c a l e s c a r s or groups of n e e d le l e a f s c a r s ( H e t t 1971). O th e r s e e d l i n g p a r a m e t e r s measured i n c l u d e d d i a m e t e r a t r o o t crown, h e i g h t , crown c o v e r , and stem growth. Stem growth was d e te r m in e d by me asu rin g t h e l e n g t h between t h e l a s t bud s c a r and t h e t e r m i n a l bud. Four one m e te r s q u a r e p l o t s were s e t up o u t s i d e each gap t o o b t a i n t h e same i n f o r m a t i o n f o r s e e d l i n g s of t h e same s p e c i e s on t h e u n d i s t u r b e d f o r e s t f l o o r . e n t i r e gap was sampled t o o b t a i n DBH f o r a l l The larger individuals. This i n f o r m a t i o n was used f o r d e s c r i p t i v e pur pose s and t o e s t a b l i s h age a n d / o r size d istrib u tio n s. Survivorship. I n c l u d e d among t h e r e l a t i v e l y few s t u d i e s o f age d i s t r i b u t i o n and s u r v i v o r s h i p o f t r e e s e e d l i n g s a r e t h o s e o f Hett and Loucks ( 1 9 6 8 ) , H e tt ( 1 9 7 1 ) , He tt and Loucks (1971) and Good and Good (1 9 7 2 ) . T h e i r methods were a p p l i e d t o s e v e r a l s e e d l i n g p o p u l a t i o n s w i t h i n t h e community t o he lp in e l u c i d a t i n g s u c c e s s i o n a l t r e n d s . H e tt (1971) found i n a s t u d y of s u g a r maple s e e d l i n g s t h a t see d crop or number o f v i a b l e seeds had l i t t l e i n f l u e n c e on t h e number of s e e d l i n g s e s t a b l i s h e d . For t h i s r e a s o n , i t was s u g g e s t e d t h a t t h e s t u d y of dynamics begin wit h ge rm in a te d s e e d l i n g s . age s t r u c t u r a l Survivorship and n a t a l i t y were o b s e r v e d f o r s e e d l i n g s i n gaps and un d e r t h e f o r e s t canopy. Percent s u r v i v a l was c a l c u l a t e d a s : number a l i v e / u n i t a r e a a t t g number a l i v e / u n i t a r e a a t t i x 100, ( H e t t and Loucks, 1971) and n a t a l i t y as number o f new s e e d l i n g / u n i t a r e a from t ^ t o t 2 * The same p l o t s t h a t were used t o sample s e e d l i n g age d i s t r i b u t i o n s were used t o c o l l e c t d a t a ons u r v i v a l and n a t a l i t y . s e e d l i n g was i d e n t i f i e d ta g during f a l l and marked with an aluminum E a r l y t h e f o l l o w i n g s p r i n g and a g a i n t h e f o l l o w i n g f a l l , p l o t s were examined t o e s t i m a t e w i n t e r and summer s u r v i v a l and n a t a l i t y . Each 1977. 15 Environmental p a r a m e t e r s . Se ve ra l en viro nm en ta l p a r a m e te r s were measured t o o b t a i n i n f o r m a t i o n t h a t might s u g g e s t r e a s o n s f o r t h e o b s e r v e d s e e d l i n g d i s t r i b u t i o n and s u r v i v a l . When d i s t u r b a n c e opens t h e f o r e s t canopy, a i r t e m p e r a t u r e , r e l a t i v e h u m id ity and l i g h t i n t e n s i t y a r e a l l changed. All of t h e s e a r e c o r r e l a t e d wit h l i g h t i n t e n s i t y and s u g g e s t t h a t l i g h t i n t e n s i t y would be t h e s i n g l e most i m p o r t a n t f a c t o r t o c o r r e l a t e with f o r e s t growth ( S h i r l e y 1932). Light energy, tem perature and hum id it y were r e c o r d e d u s i n g a p y r h e l i o m e t e r and a hygrothermograph i n each of t h e f o l l o w i n g a r e a s : a s i t e on t h e s o u t h e a s t edge of t h e v i r g i n f o r e s t where w h i t e p in e was r e g e n e r a t i n g , unde r t h e canopy ga p, and unde r t h e f o r e s t canopy on J u l y 23, 1977, August 1, 1977, A pril 29 and 30, 1978. Deer b r o w s in g . Prelim inary observation revealed th a t t r e e seedlings were b e in g h e a v i l y browsed by w h i t e t a i l e d d e e r ( Odoco ileus v i r g i n i a n u s ). P a i r e d p l o t s were e s t a b l i s h e d in both t h e gaps and f o r e s t t o i n v e s t i g a t e t h e e f f e c t o f d e e r browsing on s e e d l i n g growth and s u r v i v a l . E x c lo s u r e s c o v e r e d h a l f of t h e p l o t s w hil e t h e o t h e r h a l f remained open f o r b ro w s in g . The f o l l o w i n g y e a r h e i g h t , l e n g t h o f new stem growth, crown c o v e r a r e a and s u r v i v o r s h i p were d e te r m in e d and co mp ariso ns made between browsed and unbrowsed s e e d l i n g s . White p i n e r e g e n e r a t i o n . To o b t a i n a more com ple te p i c t u r e of t h e o v e r a l l s u c c e s s i o n a l s t a t u s o f w h i t e p i n e , two a d d i t i o n a l d e s c r i p t i v e s t u d i e s were u n d e r ta k e n in a r e a s where young w h i t e p i n e were e s t a b ­ lishing. One s t u d y was in a v i r g i n j a c k p i n e s t a n d , n e a r Hartwick Pine s (T27N, R3W, S I 1) and t h e o t h e r was in a v i r g i n w h i t e pin e s t a n d in M an is te e County, Michigan (T21N, R13W, S26 ). F i f t e e n randomly s e l e c t e d one hundred s q u a r e m e t e r p l o t s were used in t h e j a c k pine f o r e s t . 16 H e ig h t, crown c o v e r , and age of each s e e d l i n g was d e t e r m i n e d . d e te r m in e d by t h e number o f branch w h o r l s . Age was Woody s p e c i e s t h a t were a t l e a s t 1 .5 m in h e i g h t were measured f o r DBH, crown c o v e r , t o t a l h e i g h t , and number o f dead and l i v i n g s te m s . Cores were t a k e n from t h i r t y randomly s e l e c t e d t r e e s and an age d e t e r m i n a t i o n made. Age d i s t r i b u t i o n s were t h e n p l o t t e d t o make i n f e r e n c e s c o n c e r n i n g s p e c i e s r e g e n e r a t i o n . The v i r g i n w h it e p in e f o r e s t in M a n is te e County was s t u d i e d u s i n g t e n randomly s e l e c t e d two hundred s q u a r e m e te r p l o t s . DBH and t o t a l s p e c i e s with DBH g r e a t e r t h a n 2.54 cm were measured. h e i g h t o f woody Imp ortance v a lu e s were c a l c u l a t e d u s i n g d e n s i t y , b a s a l a r e a dominance, and f r e q u e n c y . v/hite p in e t r e e with one o f t h e l a r g e s t d i a m e t e r s was aged. A RESULTS AND DISCUSSON Description F ig u r e 1 i l l u s t r a t e s t h e st ud y a r e a r e l a t i v e t o t h e o v e r a l l v i r g i n forest. The t o t a l a r e a o f t h e v i r g i n s t a n d was 20 ha, reduced from t h e o r i g i n a l 34 ha d u r i n g a s to rm in t h e 1 9 4 0 ' s . A stu dy a r e a of 3.5 2 ha was chosen t o keep t h e i n c l u s i o n o f edge a r e a s ( t r a i l s and u n n a t u r a l d i s t u r b a n c e s ) t o a minimum. Small h i l l s shown a t t h e n o r th end of t h e s t a n d were i n c l u d e d as p a r t of t h e s tu d y a r e a t o i n c o r p o r a t e any topographical v a r i a b i l i t y . S p e c i e s c o m p o s i t i o n , however, was t h e same on t h e h i l l s as on t h e sandy p l a i n . The v i r g i n f o r e s t was composed of w h it e p i n e , hemlock, re d maple, s u g a r ma ple, American b e e c h , and red p i n e . In t h e G r e a t Lakes S t a t e s and p a r t s of n o r t h e a s t e r n North America, e s p e c i a l l y b e f o r e t h e lumbering e r a , t h e s e s p e c i e s were commonly found t o g e t h e r . Ta b le 1, a re vi e w of t h i r t e e n d i f f e r e n t o ld grov/th s t a n d s , shows t h a t t w e n t y - f i v e t r e e s p e c i e s o c c u r w it h w h it e p i n e in t h e c e n t r a l and e a s t e r n U n it e d S t a t e s . Oaks a r e a common a s s o c i a t e wit h w h i t e pin e in t h e v i r g i n f o r e s t a t I n t e r l o c h e n S t a t e P a r k , Michigan ( K i t t r e d g e and C h i t t e n d e n 1929). In Canada, w h i t e p i n e oc c u r s with y e l l o w and p a p e r b i r c h ( B e t u l a p a p y r i f e r a ) , balsam f i r (Abies b a l s a m e a ) , aspen ( Populus s p p . ) , and s p r u c e s ( P ic e a s p p . ) (Maissurow 193 5). H a r t w i c k ' s f i v e a s s o c i a t e d s p e c i e s , as well as red oak ( Quercus r u b r a ) and y e l l o w b i r c h , a r e p r e s e n t in more t h a n 50% of the stands. 17 hills «/ chapel parking lot trail closed N O '" ' study area / ‘monarch pine iiterpretivfc center too so 5 100 25 S c a le 1 cm = 5 0 m e t e r s Fig. 1. Location of the study area within the vi rg i n white pine f o r e s t at llartwick Pines St a te Park. 200 19 Table 1. Tr ee s p e c i e s a s s o c i a t e d with old growth w hite pine in n o r t h e a s t e r n North America. CO i— H HH HH HH e m o> •r* -C o •r— z S p e c ie s Pinus s t r o b u s Pinus r e s i n o s a Tsuga c a n a d e n s i s Acer rubrum Acer saccharum Acer s pp. Fagus g r a n d i f o l i a Quercus a l b a Quercus r u b r a Prunus s e r o t i n a F r a x i n u s americana F r a x i n u s spp. Pyrus malus Betula lu t e a Betula p a p y rife ra Betula le n ta Abies balsamea Thuja o c c i d e n t a l i s T i l i a americana Populus g r a n d i d e n t a t a Populus spp. O s t ry a v i r g i n i a n a P i c e a r ub e ns Picea glauca Magnolia acumenata C as te n ea d e n t a t a Hamamelis v i r g i n i a n a Amalanchier a r b o r e a I l e x opaca HH HH HH c c CO CO c n o> •p* •r— -C -C u u •P " z z X X X X X X X X X X X X X X Lf> • o i—i X X 00 HH HH HH HH HH • c c •H Z • c c •H z • Q. £ m =C • z X X X X X X X X X cr» HH X' X X X X X 1—1 HH HH CM 1—I i t • 1—i l—i CO o . h—1 HH iH (O E • XJ • co z c c (O c c e • 1.5 m in h e ig h t) in t h e v i r g i n f o r e s t of Hartwick Pines S t a t e Park. I.V. Rank 1 2 3 4 5 6 Species Pinus s tr o b u s Tsuga canad en sis Acer rubrum Acer saccharum Fagus g r a n d i f o l i a Pinus r e s i n o s a Total Deni s t y Absolute R e l a t i v e (# o f ind./ha) 172.5 172.5 90.0 90.0 70.0 35.0 630.0 27.38 27.38 14.29 14.29 11.11 5.56 100.01 Dominance Absolute R e l a t i v e (in2/ha) 48.43 11.91 2.92 0.96 1.22 7.16 72.60 Frequency Absolute Relative (# o f p o t s / to ta l # of plots) 66.71 16.40 4.03 1.33 1.69 9.86 100.02 C a l c u l a t e d fo ll o w i n g methods in Mueller-Dombois and E ll en b ur g (1974). 1.00 0.90 0.70 0.70 0.65 0.45 4.40 22.73 20.45 15.91 15.91 14.77 10.23 100.00 I.V. 116.82 64.23 34.23 31.53 27.56 25.65 300.02 I.V. % 38.94 21.41 11.41 10.51 9.19 8.55 100.01 25 P in u s stro b u B Mean DBH 5 7 .8 7 n*69 0 .3 7 ± P ln u a r e a ln o s a Mean DBH 5 0 .5 7 n-14 3 .7 8 ± 40. IS M> is. T suga c a n a d e n s is Mean DBH 2 7.32 f 2 .7 6 n-69 ii> fm m C IV III- - is O (— *4— O do 1. C 01 u i07 a. 10 Acer ru b ru n Mean H e ig h t 1 6 .7 8 ± 2 .0 8 n~36 20 10. ha 5 i i- I. i 'in in . FaguB g r a n d i f o l i a Mean Height 12.71 ± 2.80 n-28 ?n . 1V 10. -P=L A cer saccharum Mean H e ig h t 9 .8 3 ± 2 .3 2 n-36 10 Fi g. \ U ien =22L 26 10 He igh t (m) 1" D i s t r i b u t i o n of t r e e h e i g h t by s p e c i e s , ' U'z ■ 0/S ■ so (mean +2 3 . D . ) . 27 The a p p a r e n t d i s c o n t i n u i t y in d i a m e t e r d i s t r i b u t i o n s o f w hi te p in e between t h e 95 and 106 cm c l a s s e s and hemlock between t h e 55 and 61 cm c l a s s e s ( F i g u r e 3) s u g g e s t e d t h a t s e v e r a l i n d i v i d u a l s of each s p e c i e s e s t a b l i s h e d well b e f o r e t h e o t h e r s . Wackerman (1924) h y p o t h e s i z e d t h a t a few w hite pi ne a t Hartwick must be r e l i c s from a s to rm , and t h a t t h e y a c t e d as see d t r e e s . Assuming t h a t a gap i n s i z e c l a s s e s i n d i c a t e d a gap in ag e, t h e d i s c o n t i n u i t y appea red t o be e v id e n c e t o s u p p o rt t h e ide a t h a t some t y p e of d i s t u r b a n c e may have been r e s p o n s i b l e f o r t h e o r i g i n o f t h e p i n e s a t H a rtw ic k. In c o n t r a s t t o t h e p o s s i b l e d i s t u r b a n c e o r i g i n o f H a rt w ic k , t h e r e was no i n d i c a t i o n of w h it e p i n e assuming dominance in most of t h e 14 ha s e c t i o n o f t h e f o r e s t t h a t was d e s t r o y e d by wind in t h e 1 9 4 0 ' s . There were n in e s p e c i e s in t h i s a r e a , s i x o f which were t h e same as t h e s i x s p e c i e s in t h e u n d i s t u r b e d f o r e s t . The t h r e e o t h e r s , b la ck sp ru c e ( Pice a m a r i a n a ) , s p e c k l e d a l d e r ( Alnus i n c a n a ) , and pap er b i r c h , a r e commonly found in m oi s t h a b i t a t s . Shallow s t a n d i n g pools i n d i c a t e d p o o rl y d r a i n e d s o i l in t h e d i s t u r b e d a r e a . The l o s s o f w h it e p i n e and t h e i n t r o d u c t i o n o f new s p e c i e s may have been a r e s u l t o f n a t u r a l s o i l d r a i n a g e being i n t e r r u p t e d by a road c o n s t r u c t e d t h ro u g h t h i s p a r t of t h e f o r e s t in t h e 1930's. The a v e r a g e ages of t h e t h r e e de ci duous s p e c i e s in t h e v i r g i n f o r e s t were a l l in t h e 9 0 ' s . Red p i n e and hemlock had a v e r a g e ages o f 210 and 171 y e a r s , r e s p e c t i v e l y . L i n e a r r e g r e s s i o n a n a l y s e s showed some c o r r e l a t i o n between d i a m e t e r and age in t h e de cid uo us s p e c i e s (T a b le 2 ) , but very low c o r r e l a t i o n i n red p in e and hemlock. The a v e r a g e e s t i m a t e d age o f w h it e p i n e was 177 y e a r s (T a b le 4 ) , wit h t h e o l d e s t t r e e sampled be ing 229 y e a r s . These t r e e s a r e young, c o n s i d e r i n g t h a t w hit e p in e of 28 Ta bl e 4. Age d i s t r i b u t i o n (as % o f s p e c i e s t o t a l ) and a v er ag e age (+1 S. D .) o f t h e f i v e t r e e s p e c i e s (> 1. 5 m t a l l ) found a t Har tw ic k. Species P inu s s t r o b u s P in us r e s i n o s a Tsuga c a n a d e n s i s Acer rubrum Acer saccharum Fagus g r a n d i f o l i a 20-100 Age ( y r ) 101-150 151-225 12.5 50 .0 50 .0 50 .0 4 0.0 50.0 50.0 50.0 83.3 100.0 50.0 226+ n Mean +_ S.D. 4 .2 24 6 10 6 6 6 177 210 171 91 91 96 10.0 + + + + + + 29.35 6. 46 49.36 42.62 37.79 26.73 29 450 y e a r s and more in age have been r e c o r d e d (Harlow and H a r r a r 1968). Many t r e e s were 300 t o 500 y e a r s o l d when c u t in t h e Upper P e n i n s u l a o f Michigan (Graham 1 941); one such t r e e i n t h e E s t i v a n t P in e s n e a r Copper Harbor was 400 y e a r s o l d when c u t i n t h e 1 9 6 0 ' s . Because of v a r i a b l e growing c o n d i t i o n s of each i n d i v i d u a l , t h e r e was p r a c t i c a l l y no c o r r e l a t i o n between age and d i a m e t e r , h e i g h t o r crown c o v e r a t Hartwick (T ab le 2 ) . Most of t h e o l d growth s t a n d s were c u t when 200 t o 300 y e a r s o l d and 4 t o 7 f e e t (12 2-213 cm) in d i a m e t e r (F rot hin gha m 191 4) . In t h e f o r e s t r e p o r t e d by S t e a r n s (1950) a t r e e 76 .2 cm in d i a m e t e r had 341 rings. A f o r e s t i n Minnesota had t r e e s wit h a mean d i a m e t e r o f 71 cm and mean age of 250 y e a r s ( K i t t r e d g e 1934). In New Hampshire a stump 132 cm in d i a m e t e r had a r i n g count o f 153 (Baldwin 1 9 51 ). Hartwick f a l l s a t t h e young end o f t h e age r a ng e o f old growth p i n e which s u g g e s t e d t h a t t h e t r e e s c ould p o t e n t i a l l y s u r v i v e f o r s e v e r a l hundred more y e a r s . Windfa ll was a major c au s e of d e a t h and i t a ppea re d t h a t many of t h e s e t r e e s were s t r u c t u r a l l y weakened by h e a r t r o t . The d i s e a s e p r o b a b ly de vel ope d a f t e r s e c t i o n s of bark were d e s t r o y e d d u r i n g t h e l a s t f i r e t o burn th r o u g h t h i s a r e a , 134 y e a r s ago. Biomass and P r o d u c t i v i t y Biomass. T o t al t r e e biomass f o r Hartwick P i n e s was 681.21 m t/ h a when c a l c u l a t e d u s i n g a w h i t e p in e biomass f i g u r e base d on a wood d e n s i t y o f 0 .2 9 g/cm3. H a rt w ic k . This d e n s i t y was d e t e r m i n e d from 24 i n c r e m e n t c o r e s t a k e n a t To tal s t a n d b i o m a s s , u s i n g 0 . 3 7 g/cm3 f o r w h i t e p i n e (Brown e t a l . 1949), i n c r e a s e d t o 8 0 0 .9 5 m t / h a , w ith a w h i t e p i n e biomass o f 557.56 mt/ha. This d e m o n s t r a t e s t h e o u t s t a n d i n g and unusual c h a r a c t e r of t h i s f o r e s t , e s p e c i a l l y in r e l a t i o n t o second growth f o r e s t s o f t o d a y . It is well above a v e r a g e f o r most of t h e w o r l d ' s f o r e s t t y p e s ( T a b l e 5 and 6 ) . Table 5. Estimated biomass of standing tre es (>1.5 m t a l l ) . Stem Leaf Biomass (mt/ha) Branch*1 Root % of % of spp. spp. Absolute Total Absolute Total Absolute % of spp. Total Absolute % of spp. Total Pinus strobus 265.59 60.7 2.394a 0.5 107.23 24.5 62.44e 14.3 Tsuqa canadensis Acer rubrum Acer saccharum Fagus g ran d ifo lia Pinus resinosa Component Total 47.91 16.37 5.92 8.47 69.09 413.35 61.0 61.1 60.8 60.5 60.4 60.7 .897*> .250 .135 .159 1.049C 4.884 1.1 0.9 1.4 1.1 0.9 0.7 19.34 6.61 2.39 3.42 27.90 166.89 24.6 24.7 24.5 24.4 24.4 24.5 10.24^ 3.559 1.299 1.93b 16.31e 96.76 13.0 13.3 13.2 13.8 14.3 14.2 Species Reproductive % of spp. Absolute Total .0771 .0853 .146>* 0.0 0.0 0.2 • 0051 .006 .003m .322 0.0 0.0 0.0 0.0 Spp. Total Spp. Total as % of Component Total 437.82 64 78.53 26.78 9.74 13.99 114.35 681.21 12 4 1 2 17 100 j*Based on the average needle l i f e expectancy of 2 years and including the biomass of primary needles (Harlow and H arrar 1968). “Based on the average needle li f e expectancy of 2.5 years (Harlow and llarrar 1968). cBased on the average needle li f e expectancy of 4 years (Harlow and Harrar 1968). in d iv id u a l species values were obtained by using the ra tio B/b=S/s (Whittaker and Marks 1975). ®Based on the average value (16.63% o f the to ta l above ground biomass) fo r 100 year old Pinus contorta roots (Johnstone 1971). f Based on the average value (15% of the to ta l above ground biomass) fo r Picea abies (Lieth 1974). 9Based on the average value (15.3% of the to ta l above ground biomass) fo r mature Acer saccharum (Whittaker and Marks 1975). hBased on the average value (16% of the to ta l above ground biomass) fo r Fagus svlvatica (Lieth 1974). Based on the average cone l i f e expectancy of 1.5 years (Harlow and Harrar 1968)1 Jstam inate cones. ''Based on the average cone l i f e expectancy of 1.5 years (Harlow and Harrar 1968, Fernald 1970). ' fleer rubrum and Acer saccharum combined. n,8ased on the average cone l i f e expectancy of 1.5 years (Harlow and Harrar 1968, Fernald. 1970). 31 Tab le 6. Mean biomass and ne t pr im ary prod uc ton f o r major f o r e s t t y p e s of t h e w o rl d. F o r e s t Type T r o p i c a l Rain F o r e s t T r o p i c a l Seasonal F o r e s t Temperate Ev ergr een F o r e s t Hartwick P in e s ( w h it e p i n e ) Temperate Deciduous F o r e s t Boreal Biomass (mt /ha ) Mean Range 60-800 60-600 60-4000 60-600 60-400 450 350 350 681 300 200 Net Primary P roductivity (mt/ha/yr) Mean Range 10-35 10-25 6-25 6-25 4-20 22 16 13 7 .5 12 8 ^■Values a r e t a k e n from W h i t t a k e r (1975) and a v a r i e t y o f s o u r c e s i n c l u d i n g Art and Marks ( 1 97 1) , L i e t h ( 1 9 7 5 ) , Rodin and B a z i l e v i c h (1967, 1 9 6 8 ), Waring and F r a n k l i n (1979) and Woodwell and W h i t t a k e r (1968). 32 Only t h e c o n i f e r o u s s t a n d s of t h e P a c i f i c Northwest with up t o 4000 mt/ha and pe rh ap s t h e e u c a l y p t u s f o r e s t s of A u s t r a l i a f a r exceed t h e biomass of Hartwick (Waring and F r a n k l i n 1979 ). have been r e c o r d e d : S e v e ra l comparable s t a n d s a Tsuga c a n a d e n s i s s t a n d w i t h 610 m t / h a , and a Tsuga-Rhododendron s t a n d with 511 m t/ h a in t h e U.S.A. ( W h i t t a k e r 1966); A b i e s , Ts uga , and Quercus i n Nepal w it h 520 t o 682 m t/h a (Yoda 1968, c i t e d by Art and Marks 1971); Quercus in both t h e U.S.A. and U . S .S .R . with v a lu e s o v e r 400 mt/h a ( W h i t t a k e r 1966, Rodin and B a z i l e v i c h 1967). White p in e biomass from Hartwick a lo n e i s n e a r or above (de pen din g on wood d e n s i t y ) t h e t o t a l biomass o f 515 mt/ha f o r a Fagus- Acer f o r e s t in Michigan (Murphy, P. 6. and G. K. Kroh, Biomass and Net Prim ary P r o d u c t i v i t y of a V i r g i n Beech-Maple F o r e s t in Mi chigan, Michigan S t a t e U n i v e r s i t y , in p r e p a r a t i o n ) . This was p ro b a b ly a r e s u l t of t h e l a r g e w h i t e p in e ba sa l a r e a of 4 8 .4 m^/ha compared t o t o t a l b a s a l a r e a f o r t h e beech -ma ple s t a n d o f 4 2 . 6 m^/ha. White pin e and r e d p i n e made up a d i s p r o p o r t i o n a t e amount of t h e biomass in comparison t o t h e i r im po rt an ce v a l u e p e r c e n t a g e s . White p i n e was 64% o f t h e biomass and red p in e 17%, w hil e t h e i r im po r ta nc e v a lu e p e r c e n t a g e s were 3 8 .9 and 8 . 6 , r e s p e c t i v e l y . Biomass o f t h e f o u r o t h e r s p e c i e s was much l e s s t h a n t h e i r im po r tan c e v a l u e s might i n d i c a t e . The l a c k of r e l a t i o n s h i p between im port an ce v a l u e and biomass i n d i c a t e s t h e l i m i t a t i o n in u s in g im p o r ta n c e v a l u e s t o d e s c r i b e some f o r e s t s . A better i n d i c a t o r of im p o r t a n c e , in some i n s t a n c e s , s h oul d i n c l u d e biomass and p e rh a p s p r o d u c t i o n as a m o d i f i e r . The a l l o m e t r i c e q u a t i o n r e l a t i n g w h i t e p in e DBH and stem volume, a l o n g with s p e c i f i c g r a v i t y , was used t o e s t i m a t e biomass ( T a b l e 2 ) . The a l l o m e t r i c e q u a t i o n proved t o be a good p r e d i c t o r , with a c o e f f i c i e n t of 33 d e t e r m i n a t i o n ( r ^ ) o f 0.9 1 (n=1 5) . Even though w hit e p i n e stems may vary t o some d e gre e in growth form between s i t e s t h i s e q u a t i o n s hould prove t o be o f v a l u e in s i m i l a r s t u d i e s o f o ld growth w hit e p in e where r e s t r i c t i o n s p r e v e n t d e s t r u c t i v e sam p li ng . White p in e wood d e n s i t y was 0 .2 9 g/cm3 , 22% lo w e r t h a n . 3 7 g/cm3 l i s t e d by Brown e t a l . (1949). Bark d e n s i t y was 0 .5 6 g/cm3 , w i t h i n t h e ra nge of 0 . 4 0 2 - 0 . 7 1 4 g/cm3 gi ve n by Martin and C r i s t (1968) f o r Michigan and V i r g i n i a sp ec im e n s. Bark c omp ris ed 8.7% of t h e t o t a l stem biomass. Stem biomass was 60.7% and l e a f biomass 0.7% o f t h e t o t a l biomass. Stem biomass p e r c e n t a g e a p pe a re d t o be c o n s t a n t a c r o s s s p e c i e s with d i f f e r e n t age and s i z e c l a s s e s , with s i n g l e s p e c i e s v a l u e s w i t h i n 0.7% o f each o t h e r . White p i n e l e a f biomass o f 0.5% o f w h i t e p i n e t o t a l was low compared t o t h e o t h e r s p e c i e s with l e a f biomass p e r c e n t a g e s between 0 . 9 and 1 . 4 . Kira and S h id e i (1967) emphasize t h a t l e a f biomass of a t r e e in a c l o s e d s t a n d w i l l re a ch an upper l i m i t , w hi le stem biomass i s s t i l l increasing. The amount o f l e a f biomass may be a l i m i t i n g f a c t o r t o growth and s u r v i v a l i f t h i s r e d u c t i o n in t h e p e r c e n t a g e of l e a f biomass continues. I t would not be s u r p r i s i n g t o f i n d t h i s o c c u r r i n g with t h e w h it e pin e a t H a rt w ic k . Productivity. T o t al ne t pr im ary p r o d u c t i o n (NPP) f o r H a r tw ic k , 7 .5 m t / h a / y r , i s a t t h e low end o f t h e ra ng e s r e p o r t e d in t h e l i t e r a t u r e f o r many of t h e w o r l d ' s f o r e s t t y p e s ( T a b l e s 6 and 7 ) . I t i s comparable t o a woodland, s h r u b l a n d , o r t e m p e r a t e g r a s s l a n d ( W h i t t a k e r 1975) and f a l l s w i t h i n t h e range f o r t e m p e r a t e e v e r g r e e n f o r e s t s . t h e c o n c l u s i o n s o f Westla ke ( 1 9 6 3 ) , Kira and Sh id e i Thi s does not s u p p o r t ( 1 9 6 7 ) , and Rodin and B a z i l e v i c h ( 1 9 6 8 ) , t h a t c o n i f e r f o r e s t s have t h e h i g h e s t NPP. These a u t h o r s l i s t f i g u r e s f o r c o n i f e r f o r e s t s o f 10-28 m t / h a / y r in warm, Table 7. Net primary productivity (kg/ha/yr) o f the s ix tree sp ecies (>1.5 m t a l l ) in the virgin Pinus strobus L. fo r e st. Net Annual P roductivity (kg/ha) Species Stem Leaf Branchc Rootd Reproductive X of spp. X of spp. X of spp. X of spp. X of spp. Total Absolute Total A6so1ute Total Absolute Total Absolute Total Absolute 1239.9 36.2 695.3 Tsuqa canadensis Acer rubrum 267.6 Acer saccharum 175.0 Faqus g ran d ifo lia 226.1 384.8 Pinus resinosa Component Total 2988.7 44.0 39.0 41.5 42.4 43.0 39.6 Pinus strobus 113.5a 1140.2b 358.9 250.0 135.3 158.6 262.2 2418.7 3.3 33.3 22.7 36.4 32.1 29.8 29.3 32.1 500.6 14.6 291.5 8.5 280.7 108.0 70.7 91.3 155.4 1206.7 17.8 15.7 16.8 17.1 17.4 16.0 148.6 58.0 38.1 51.5 90.8 678.5 9.4 8.5 9.0 9.7 10.1 9.0 51. ie 85.4^ 97.3 1.5 2.5 6.2 4.69 5.5 2.1 246.0 0.4 1.0 0.2 3.3 a Pinus strobus bud sc a le s. bpinus strobus leaves. c Individual species values were obtained by m ultiplying the to ta l amount of branch production by the individual species percentage of the to ta l stem production. ^Individual species values were obtained by using the ra tio R/r=S/s. R=root biomass, r=root production, S-stem biomass, system production. eP is t i la t e cones, fstam inate cones. 9Acer rubrum and Acer saccharum combi ned. Spp. Total as X of Component Spp. Total Total 3422.2 45 1580.8 685.9 421.4 533.0 895.3 7538.6 21 9 6 7 12 100 35 te m p e r a t e and s u b a r c t i c a r e a s ; however, Rodin and B a z i l e v i c h (1968) a l s o c i t e a c o m p a r a t i v e l y low v a lu e o f 7 . 0 m t / h a / y r f o r t h e t e m p e r a t e zone. These a u t h o r s c oul d have based t h e i r c o n c l u s i o n on a sample skewed toward young s t a n d s i n which ne t p ri m ar y p r o d u c t i o n i s h i g h e r . As p r e v i o u s l y m e n ti o n e d , ou t of 291 biomass and p r o d u c t i v i t y s t u d i e s c i t e d by Art and Marks (1971) t h e a v e r a g e age o f n a t u r a l s t a n d s was 4 5 . 8 y e a r s and p l a n t a t i o n s 2 9 .0 y e a r s . White p i n e r e a c h e s i t s peak growth between t h e ages o f 40 and 115 y e a r s a c c o r d i n g t o B a r r e t t e t a l . y e a r s a c c o r d i n g t o Cope ( 1 9 3 2 ) . (1976) and a t 26 Woodwell and W h i t t a k e r (1968) s u g g e s t t h a t NPP of f o r e s t s w ith a l a r g e b io m a s s, such as t h e cove f o r e s t s of t h e G re at Smoky Mountains N a ti o n a l Park (600 m t / h a ) ( W h i t t a k e r 1 9 66), w i l l be 2 .0 -2 .5 % o f t h e bio m a s s, t w i c e t h a t o f H artw ic k. The NPP v a l u e s f o r Hartwick and t h e Fa gus -A cer f o r e s t in Michigan mention ed p r e v i o u s l y , with an NPP v a l u e o f 8 . 4 m t / h a / y r (Murphy, P. G. and G. K. Kroh, Biomass and Net Primary P r o d u c t i o n o f a V i r g i n Beech-Maple F o r e s t in Michigan, Michigan S t a t e U n i v e r s i t y , in p r e p a r a t i o n ) , s u g g e s t a s u b s t a n t i a l decrease in NPP w it h s t a n d age. T o t al ne t stem p r o d u c t i o n f o r H a r t w i c k , 2 ,9 8 9 k g / h a / y r , i s l e s s t h a n h a l f t h e ne t stem p r o d u c t i o n f o r a 15 y e a r o ld w h i t e p i n e p l a n t a t i o n in North C a r o l i n a (Swank and S c h r e u d e r 1973). The a v e r a g e r a d i a l incre men t o f Hartwick w h i t e p i n e was 0 . 7 4 mm, o n l y 29% of an o ld growth w h i t e p i n e f o r e s t in New Hampshire (Baldwin 1 9 51), and l e s s t h a n t h e 1.2 2 t o 4 . 0 5 mm measured from t h e f i r s t t e n y e a r s of growth by w h i t e p i n e in n o r t h w e s t e r n P e n n s y l v a n i a (Lu tz and McComb 1935 ). R e g r e s s i o n a n a l y s i s between crown volume and w h i t e p i n e stem p r o d u c t i o n o r stem biomass i n d i c a t e d l i t t l e c o r r e l a t i o n (T a b le 2 ) . f o r 36% of i t s t o t a l The main stem o f w hi te p in e a t Hartwick a cc o u n te d n e t p r o d u c t i o n , w h i l e i n t h e o t h e r s p e c i e s t h e stem 36 comp ris ed a p p r o x i m a t e l y 40%. These v a lu e s f a l l w i t h i n t h e range o f 35-40% f o r f o r e s t s i n f a v o r a b l e e nv ir o n m e n ts (Woodwell and W h i t t a k e r 1968 ). Leaf l i t t e r f o r a l l s p e c i e s combined r e p r e s e n t e d 62% o f t o t a l litter, not i n c l u d i n g i n p u t from t h e main s te m ; branch l i t t e r r e p r e s e n t e d 31% and r e p r o d u c t i v e l i t t e r 6%. White p in e l e a f l i t t e r a l o n e was 66% o f i t s t o t a l l i t t e r , branch l i t t e r 26% and r e p r o d u c t i v e l i t t e r 7%. These v a l u e s compare f a v o r a b l y with o t h e r Pinus f o r e s t s r a n g i n g from 60-69% f o r l e a f l i t t e r , 33-36% f o r branch l i t t e r and 2-17% f o r r e p r o d u c t i v e l i t t e r and Gorham 1964). (Bray The s m a l l e r v a l u e f o r Hartwick branch l i t t e r c ould have been a r e s u l t o f reduc ed lower branch p r u n i n g in l a r g e r p i n e s . Seasonal v a r i a t i o n in t h e amount of l e a f l i t t e r c o l l e c t e d i n d i c a t e d t h a t maples and beech dropped v i r t u a l l y a l l o f t h e i r l e a v e s i n October and November ( F i g u r e 5 ) . S i m i l a r l y , t h e c o n i f e r o u s s p e c i e s dropped a p p r o x i ­ m a t e l y 98% o f t h e i r annual l e a f l i t t e r i n O c to be r and November; t h e y r e t a i n e d t h e i r y o u n g e s t n e e d l e s , however, l o s i n g a few of t h o s e th r o u g h o u t t h e r e s t of t h e y e a r . Large s t a n d a r d e r r o r s in t h e s e f i g u r e s were a r e s u l t o f t h e l i m i t e d number of samples t h a t c ould be t a k e n w h il e ke epi ng v i s u a l and human impact t o a minimum. R e p r o d u c ti v e and p h o t o s y n t h e t i c s t r u c t u r e s were a r e l a t i v e l y l a r g e p a r t of t h e t o t a l p r o d u c t i o n . R e p r o d u c t i v e s t r u c t u r e s a t Hartwick were only 0.05% o f t h e t o t a l biomass but 3.3% o f t h e t o t a l NPP. 2 2 .7 t o 36.4% of t o t a l Le a f NPP was i n d i v i d u a l s p e c i e s NPP, w h i l e l e a v e s comprised l e s s t h a n 2% o f t h e t o t a l biomass of each s p e c i e s . White p i n e had one o f t h e h i g h e r v a l u e s f o r l e a f NPP as a p e r c e n t a g e o f s p e c i e s t o t a l a t 33.3%, w h il e hemlock was t h e lo w e st a t 22.7%. bud s c a l e s a l o n e made up 5% o f t h e t o t a l t u r n was 32% o f t h e t o t a l NPP. The s t r u c t u r a l l y small w h i t e pi ne l e a f NPP ( 2 . 4 m t / h a / y r ) , which in H a r t w i c k ' s l e a f p r o d u c t i o n in comparison 37 900 t 800 - 200- 150 — Plnus Plnus — Tsuga — — Plnus strobus (BudScales) strobus (SecondaryLeaves) canadensis reslnosa f 1} I I I / // | / 100- Fall (kg/ha) 50 - Leaf Litter 300 150 - 100 50- A cer rubrum A c e r sacch aru m Fagus g r a n d l f o l l a S am p lin g D a te s (M onths) Fi g . 5. C o n i f e r o u s and d e c i d u o u s l e a f l i t t e r f a l l by month. 38 t o t h e mean l e a f p r o d u c t i o n of 2 . 8 m t / h a / y r f o r f i v e Pinus s i t e s , 3-69 y e a r s o l d (Bray and Gorham 1964) s u g g e s t s a s l i g h t d e c r e a s e in l e a f p r o d u c t i o n with age. S u c c e s s io n Tree d i a m e t e r , h e i g h t and age d i s t r i b u t i o n . Although whit e pine was once c o n s i d e r e d t o be a component o f climax f o r e s t s ( D e t w i l e r 1933), i t i s t o d a y more commonly r e g a r d e d as a s u c c e s s i o n a l s p e c i e s (Graham 1941). I t is a p i o n e e r on d i s t u r b e d or open s i t e s o r i s pre ced ed by j a c k p i n e or oak and r e p l a c e d by maples and beech (G ra nt 1934, K i t t r e d g e 1934, Morey 1936, C li n e and S p u r r 1942, Graham 1941, S t e a r n s 1950). By comparing canopy t o u n d e r s t o r y t r e e s , Braun (1950) c o n cl ud e d t h a t t h e s u c c e s s i o n a l s e r i e s f o r Hartwick w i l l be from w h i t e p i n e - r e d p in e t o w h it e pine-hemlock with hardwoods t o hemlock hardwoods o r hardwoods a l o n e . S u c c e s s i o n a l t r e n d s can be i n f e r e d from p a t t e r n s of d i a m e t e r and h e i g h t d i s t r i b u t i o n s among t h e ma jor t r e e s p e c i e s but with c a u t i o n b e c a u s e - t h e next s u c c e s s i o n a l s t a g e is not always r e p r e s e n t e d by t h e s p e c i e s wit h t h e l a r g e s t p r o p o r t i o n of sm aller in d iv id u a ls. These d a t a s hould be viewed as one p i e c e of ev ide nc e t h a t , when combined with o t h e r o b s e r v a t i o n s on s u c c e s s i o n , w i l l l e a d t o more c o n f i d e n t c o n c l u s i o n s . At Hartwick t h e r e were no w h it e or r e d pin e ma tur e t r e e s in s i z e c l a s s e s l e s s t h a n 26 cm in d i a m e t e r o r 22 m i n h e i g h t , p o s s i b l y i n d i c a t i n g t h e i r i n a b i l i t y t o r e g e n e r a t e ( F i g u r e s 3 and 4 ) . Red ma ple , b e e c h , and s u g a r maple, p r e s e n t in t h e s m a l l e r s i z e c l a s s e s , can be e x p e c t e d , t h e r e f o r e , t o have a c o m p e t i t i v e edge over pin e s e e d l i n g s in r e p l a c i n g t h e m at ur e w h i t e and red p i n e . Hemlock was d i f f i c u l t t o i n t e r p r e t be ca us e i t i s i n t e r m e d i a t e in s i z e between t h e two groups and shows a d e c r e a s e i n t h e small s i z e c a t e g o r i e s . I t a pp ea re d t o be an u n d e r s t o r y t o l e r a n t s p e c i e s and y e t shows s i g n s o f not r e p l a c i n g i t s e l f . 39 The age of t h e t h r e e c o n i f e r s a ve rage d more t h a n 170 y e a r s , w hile t h e t h r e e hardwood s p e c i e s were grouped n e a r 90 y e a r s (T able 4 ) . The d a t e o f e s t a b l i s h m e n t o f t h e o l d e s t hardwood s p e c i e s c o r r e s p o n d e d t o t h e d a t e of t h e l a s t f i r e t h a t burned t h r o u g h t h i s a r e a sometime between 1846-1856. I t i s l i k e l y t h a t hardwoods e s t a b l i s h e d th e m s e lv e s p r i o r t o 1846 and t h a t t h e f i r . e e l i m i n a t e d them from competing with t h e s u r v i v i n g p i n e s . P o s s i b l y b e ca u s e f i r e was no l o n g e r a f a c t o r , a t t h e ti m e of t h i s s t u d y , hardwoods were once a g a i n a b l e t o compete f o r dominance i n t h e canopy gaps caused by t h e d e ath o f l a r g e w h it e p i n e . This s u p p o r t s t h e id e a t h a t f i r e i s a ma jor f a c t o r in p e r p e t u a t i n g w h it e p in e f o r e s t s (F rot hin gham 1914, Maissurow 1935, 1941). Canopy gap d e s c r i p t i o n . Bergman (1923) c o n s i d e r e d w h i t e p in e t o be a c li m a x s p e c i e s based on o b s e r v a t i o n s of a s t a n d where w h i t e and red p i n e s e e d l i n g s were t h e most numerous o f a l l t r e e s p e c i e s in w i n d f a l l openings. However, s i m i l a r t o t h e p r e s e n t o b s e r v a t i o n s a t H a rtw ic k, w h it e p in e were a b s e n t in t h e s a p l i n g c a t e g o r y . Bergman had c o r r e c t l y s u g g e s t e d t h a t stucjy of canopy openings i s i m p o r t a n t in u n d e r s t a n d i n g s u c c e s s i o n , bu t f a i l e d t o ac c ount f o r t h e a p p a r e n t la c k o f s e e d l i n g survivorship. S in c e Bergman, t h e gap -ph ase co n ce p t has d e v e l o p e d , s t r e s s i n g t h e im po r tanc e o f d i s t u r b a n c e openings in re p la c e m e n t o f canopy s p e c i e s (Watt 1947, Bray 1956, O l i v e r and St e p h e n s 1977). The s i z e of t h e canopy opening i s d e te r m in e d by t h e t y p e of d i s t u r b a n c e or d e s t r u c t i o n , which in t u r n i n f l u e n c e s s p e c i e s r e c r u i t m e n t i n t o t h e opened a r e a . S he e t d e s t r u c t i o n cau se d by f i r e opens l a r g e a r e a s , whereas t h e more common d e a th o f s i n g l e t r e e s opens small a r e a s (Grubb 1977 ), such as t h o s e ca us e d by windthrow a t H a rt w ic k . However, q u i t e o f t e n when one t r e e i s blown o v e r s e v e r a l t r e e s a r e t a k e n down with i t (T a b le 8 ) . 40 Table 8 . Comparison o f t h e number o f t r e e s t h a t d i e d , c r e a t i n g t h e 21 gap f o r m a t i o n s , w it h t h e r e l a t i v e d e n s i t y o f t h e l i v i n g t r e e s . Species Pin us s t r o b u s P in us r e s i n o s a Tsuga c a n a d e n s i s Acer spp. Conifer Unknown Total Number Dead Mean Number Dead P e r Gap P e r c e n t of T o t al Dead R e l a t i v e D e n s it y o f Li vin g 44 11 5 5 3 8 76 2 .0 0. 5 0 .2 0 .2 0.1 0 .4 3 .4 57.9 14.5 6 .6 6 .6 3.9 10.5 100.0 27 .4 5 .6 2 7.4 28 .6 41 In t h e p r e s e n t s tu d y t h e t o t a l f u n c t i o n a l gap a r e a c o n s t i t u t e d 15% of t h e t o t a l sample a r e a w h i l e t h e t o t a l s t r u c t u r a l on ly 6% ( F i g u r e 6 ) . gap a r e a c o n s t i t u t e d Some windthrows a t Hartwick may have been a r e s u l t o f h e a r t r o t t h a t p o s s i b l y began when t h e f i r e 130 y e a r s ago burned t h r o u g h s e c t i o n s o f t h e bark ex p o si n g t h e wood, and making t h e t r e e s more susceptible to disease and i n s e c t damage. y e a r s , t w e n t y - o n e gaps have formed in t h e s tu d y a r e a , t h e most r e c e n t of which was f i v e y e a r s o l d . During t h e p a s t one hundred Gap ages i n d i c a t e d t h a t many o f t h e gaps formed a t t h e same t i m e , p ro b a b ly d u r i n g s t o r m s . P e r c e n t of t o t a l dead t r e e s o f w h it e and red p i n e was more t h a n t w i c e t h e i r r e l a t i v e d e n s i t y among l i v i n g t r e e s . T h is was much h i g h e r t h a n any o f t h e o t h e r s p e c i e s , in d ic a t in g a higher death r a t e . S i z e , ag e, and number o f dead t r e e s f o r each gap, i n c l u d i n g a v e r a g e s f o r t h e s e p a r a m e t e r s , a r e l i s t e d in T a b le 9. S e e d l i n g d e s c r i p t i o n , age and s i z e d i s t r i b u t i o n . Of t h e s e e d l i n g s found i n g a p s, re d maple, s u g a r maple and w h i t e p i n e had imp or tan ce va lu e p e r c e n t a g e s t h r e e t o e i g h t t i m e s g r e a t e r t h a n any o t h e r t r e e s p e c i e s (T a b le 1 0 ) . These t h r e e were a l s o most i m p o r t a n t und er t h e f o r e s t canopy, where im p o r ta n c e v a l u e p e r c e n t a g e s f o r red and s u g a r maple were 10-19% g r e a t e r , and w h i t e p in e 44% l e s s , t h a n under t h e canopy gap. This indicates the r e la tiv e a b i l i t y o f r e d and s u g a r maple t o e s t a b l i s h and grow b e t t e r t h a n w h i t e p i n e unde r a canopy. in a b so lu te values of a l l However, t h e d i s t i n c t drop s p e c i e s , e s p e c i a l l y w h it e p i n e , from t h e gap t o t h e canopy u n d e r s t o r y i n d i c a t e s t h a t t h o s e s p e c i e s do not do as well under t h e canopy. Red maple had f o u r t i m e s t h e s e e d l i n g d e n s i t y as s u g a r maple in t h e gap and unde r t h e canopy. In t h e gap, w h it e p i n e d e n s i t y was 11% g r e a t e r th a n s u g a r maple and unde r t h e canopy i t was 42% l e s s . However, s u g a r maple dominated crown c o v e r a r e a in t h e gap (2796 cm2/m2) and under 42 220 200 180 160 P a th B u ffe r Zone Meters 120 P a th B u ffe r Zone 0 20 40 60 80 M eters 100 120 160 F i g . 6. L o c a t i o n and s i z e o f s t r u c t u r a l ( - ) and f u n c t i o n a l ( - - ) gaps w i t h i n t h e sample a r e a . The p a th i n c l u d e s t h e a r e a w i t h i n t h e f o r e s t e l i m i n a t e d from t h e s t u d y t o r e duc e t h e edge e f f e c t . 43 Tabl e 9. The ag e, s i z e and number o f dead t r e e s a s s o c i a t e d with each of t h e i n t e n s i v e l y s t u d i e d gaps and t h e mean v a l u e s f o r a l l g a p s . Gap 11 14 17 19 15 1 8 10 Mean f o r a l l 21 gaps F u n c ti o n a l (m2 ) 289 244 495 626 210 242 168 274 251 a No downed t r e e s were v i s i b l e . removed. Structural (m2 ) 163 95 263 347 95 121 84 121 113 Age (y e a r ) Number o f dead t r e e s 5 5 33 37 50 63 90 100 40 They c ould have been decomposed or 6 5 7 13 0a 4 3 5 3 .6 Table 10. Importance values9 (I .V .) fo r the woody seed lin gs (<1.5 m in height) found in the gaps and closed fo r e st. Dominance*5 Density Absolute # of ind./m? Gap Forest Acer rubrum Acer saccharum Pinus strobus Tsuqa canadensis Amelanchier sp. Acer spicatum Lonicera sp. Faqus q ran d ifo lia Total 11.4 2.9 4.2 0.7 0.8 0.0 0.4 0.1 20.5 6.3 1.6 0.9 0.2 0.1 0.4 0.0 0.0 9.5 R elative Gap Forest 55.6 14.3 20.7 3.4 3.6 0.0 2.1 0.3 100.0 65.9 17.0 9.8 2.0 1.4 4.0 0.0 0.0 100.1 Absolute cm2/m2 Gap Forest 2101.6 2796.3 218.6 27.4 202.1 0.0 108.8 29.5 5484.3 515.8 995.9 25.2 5.9 11.5 139.8 0.0 0.0 1694.1 C a lc u la te d following methods in Hueller-Dombois and Ellenburg (1974). bBased on crown cover. Relative Gap Forest 38.3 51.0 4.0 0.5 3.7 0.0 2.0 0.5 100.0 30.4 58.8 1.5 0.3 0.7 8.3 0.0 0.0 100.0 Frequency Absolute # of p lo ts / to ta l # of p lo ts R elative Gap Forest Gap Forest 0.9 0.7 0.6 0.4 0.4 0.0 0.1 0.1 3.2 0.8 0.6 0.2 0.2 0.1 0.1 0.0 0.0 2.0 30.0 22.0 18.0 12.0 12.0 0.0 4.0 2.0 100.0 40.6 28.1 12.5 9.4 6.2 3.1 0.0 0.0 99.9 I.V. % Gap Forest 41.3 29.1 14.2 5.3 6.4 0.0 2.7 0.9 99.9 45.6 34.6 7.9 3.9 2.8 5.1 0.0 0.0 99.9 45 t h e canopy (996 cm2 /m2 ), while red maple was second (2102 and 516 cm2/m2 ) (T a b le 1 0 ) . The crown c o v e r a r e a o f w h i t e p i n e i n t h e gap was o nl y 8% a nd, under t h e canopy only 3% o f s u g a r m a p l e ' s r e s p e c t i v e v a l u e s . The average i n d i v i d u a l crown c o v e r f o r gap was f i v e t i m e s l a r g e r th a n re d maple, and 20 t i m e s l a r g e r t h a n w hi te pine. s u g a r maple s e e d l i n g s in t h e f o r e s t and Sugar maple s e e d l i n g s ho ot growth was t h r e e t o s i x ti m e s g r e a t e r t h a n t h e o t h e r two s p e c i e s ( F i g u r e 7 ) . Under t h e f o r e s t canopy, s u g a r maple s e e d l i n g s grew an a v e r a g e 5 cm/yr w h il e w h i t e p i n e grew l e s s th a n 1 c m /y r; t h e d i f f e r e n c e was even g r e a t e r in t h e gap, with s u g a r maple growing a p p r o x i m a t e l y 10 cm/yr and and beech s e e d l i n g s were rare, less w hit e p i n e l e s s t h a n 1 c m /y r. Hemlock t h a n 1/m2 , and red p i n e was a b s e n t , i n d i c a t i n g a com ple te f a i l u r e o f t h i s s p e c i e s t o produce s e e d l i n g s . The a v e r a g e s of s i x s e e d l i n g p a r a m e te r s measured in gaps of d i f f e r e n t ages a r e i l l u s t r a t e d i n F i g u r e 8. S ta n d a rd e r r o r s were not i n c l u d e d b e c a u s e , in a lm os t every c a s e , t h e y were n e a r l y one h a l f t h e mean v a l u e . T h e r e f o r e , t h e s e f i g u r e s only s u g g e s t changes t h a t may o c c u r as t h e gap ages. Most of t h e s e e d l i n g p a r a m e t e r s measured were a t a maximum when gaps were between 5 and 40 y e a r s o l d . A f t e r s e v e r a l decades of gro w th, maples have p a r t i a l l y c l o s e d t h e 33- t o 6 3 - y e a r - o l d canopy g a p s, and c o m p l e t e l y c l o s e d t h e 9 0 - y e a r - o l d gap, s u p p r e s s i n g growth o f new seedlings. The s e e d l i n g s a l s o showed re duced e v id e n c e of brows ing. In t h e 1 0 0 - y e a r - o l d gap, s e v e r a l o f t h e mature hardwoods d i e d , c r e a t i n g a second gap in which s e e d l i n g s were r e l e a s e d ( F ig u r e 8 ) . The d a t a show t h a t t h e r e was a r a p i d i n c r e a s e in s e e d l i n g growth, with s u g a r maple d i s p l a y i n g t h e g r e a t e s t r e s p o n s e , in t h e e a r l y y e a r s a f t e r gap f o r m a t i o n . Red ma ple, be c a u s e of i t s d e n s i t y , a t t a i n e d t h e l a r g e s t im po r tanc e v a l u e , which r e s u l t e d in a s h a r i n g of canopy dominance by t h e two maple s p e c i e s . 612.8 20i 30 12C U lOf S 25 -p . 01 20 Mean Grown Cover (cm ) AR AR AR AR Forest Gap Sp ecies Forest Gap S p ecies Forest Gap S p ecies Fig. 7. Average s e e d l i n g crown cover and shoot growth, and perc ent ag e of browsed s e e d li n g s in t h e gaps and f o r e s t . Legend: AS=Acer saccharum, AR=Acer rubrum, PS=Pinus s t r o b u s . 47 M«an F o r« « t V a lu e s AS— . 3 AJt-1 .6 P S - 1 .1 T AS i S s £ 1200 - AS 1 1001 700* ■600< <0 0 . 300. :oo- Fig . 0. Six s e e d l i n g p a r a m e t e r s measured in gaps o f d i f f e r e n t a g e s , s u g g e s t i n g te mp ora l c h a n g e s . The mean v a l u e s f o r s e e d l i n g s unde r t h e f o r e s t canopy a r e a l s o g iv e n . Legend: AS=Acer s ac c har um , AR=Acer r u br um , PS=Pinus s t r o b u s , % Browse = P e r c e n t a g e o f SeedTTngs Browsed. 48 Red maple, had a high p r o b a b i l i t y o f r e a c h i n g t h e canopy be cau se of t h e l a r g e number of i t s s e e d l i n g s , and s u g a r maple be ca us e of i t s e a r l y v i g o r o u s growth. Comparisons o f s e e d l i n g v a l u e s between t h e f o r e s t with a w h i t e p in e - d o m i n a t e d o v e r s t o r y and t h e o l d e r gaps wit h a maple-dominated o v e r s t o r y seems t o i n d i c a t e t h a t s u g a r maple does not do as well under i t s own canopy ( F i g u r e 8 ) . White p i n e s e e d l i n g s were produced in numbers e q u i v a l e n t t o s u g a r maple, bu t t h e y grew very p o o r l y , both in t h e gap and unde r t h e canopy, and c o u ld not a d e q u a t e l y compete f o r canopy dominance. There were t o o few beech s e e d l i n g s t o a ll ow a s tu d y t o e x p l a i n i t s s u cc e ss in r e a c h i n g t h e canopy. One p o s s i b l e e x p l a n a t i o n i s t h a t beech s e e d l i n g s have a g r e a t e r s u r v i v o r s h i p t h a n s u g a r maple ( F o r c i e r 197 5) , perhaps as a r e s u l t o f e s t a b l i s h i n g from r o o t s p r o u t s . Age and s i z e d i s t r i b u t i o n s of s u g a r maple, re d maple, and w hit e p i n e , w i t h i n gaps o f d i f f e r e n t a g e s , i n d i c a t e t h e s u r v i v a l c a p a b i l i t i e s o f t h e s e species (Figures 9-14). In t h e f i v e - y e a r - o l d gap, 67% o f t h e w hite pine were in t h e y o u n g e s t age c a t e g o r y . Eig ht p e r c e n t o f w h i t e p i n e and o v e r 50% o f both red and s u g a r maple were o l d e r t h a n s i x y e a r s . This r e f l e c t s t h e a b i l i t y o f a l l t h r e e s p e c i e s t o produce s e e d l i n g s under t h e f o r e s t canopy b e f o r e a gap fo r m s, b u t s e e d l i n g s s u r v i v e only when a gap forms. In t h e f i v e y e a r o l d gap, s u g a r maple s u r v i v e d and dominated t h e o l d e r age c a t e g o r i e s , p o s s i b l y by t a k i n g a d v an ta g e of small gaps formed by t h e l o s s o f b r a n c h e s from t h e o r i g i n a l canopy t r e e . In t h e 33- and 3 7 - y e a r - o l d ga ps, t h e o l d e s t w h i t e p in e were in t h e 16 t o 18 y e a r c l a s s , i n d i c a t i n g t h e i r i n a b i l i t y t o s u r v i v e i n a gap ; in t h e same g a p s , r e d maple s u r v i v e d t o t h e e s t i m a t e d age of 66 and s u g a r maple t o 56 ( F i g u r e 1 0 ) . A f t e r 33 y e a r s , when t h e maples have p a r t i a l l y f i l l e d t h e gap in t h e canopy, t h e age and s i z e d i s t r i b u t i o n changed a b r u p t l y , as 49 P ln u s s tr o b u s 20 A cer ru b ru n «m30 A cer sacch sru w U0 30 20 10 Age (yr) DBH (cn) Fi g . 9. D i s t r i b u t i o n of age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m in h e i g h t ) o f t h e t h r e e ma jor s p e c i e s found in 5 - y e a r - o l d gaps. P ln u s s tr o b u s Acer rubrum « J*0H o o £ v 20. £ CL Accr gaccharum 30. 20 1 0- 8 10 12 Age (yr) 1U 16 18 20 a 3 l* 5 6 7 10 DBH (cm) Fi g . 10. D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m i n h e ig h t) and DBH ( i n d i v i d u a l s >1.5 m i n h e i g h t ) o f the th r e e major species found in a 33and 3 7 - y e a r - o ld gap. 50 97 < * P in u s a tro b u R 20 10 Acer rubru« lO Acer iiccharui 30* 20 10* DBH (cn) F ig . 11. D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m in h e i g h t ) and DBH ( i n d i v i d u a l s >1 .5 m in h e i g h t ) of t h e t h r e e m a jo r s p e c i e s found i n a 5 0 - y e a r - o l d gap. P ln u s R tr o b u s UO3a 2a 10. 50 Acer rubru« 50 30- 2a ia Acer sa cch arin <>o > 30 20 102 4 ^ J 10 12 " 7 1 A «e ( j r ) 16 10™ 10 15 20 45 jO 35 <*0 05 ^0 DBH ( c a ) F i g . 12. D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m i n h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m i n h e i g h t ) o f th e t h r e e major species found i n a 5 3 - y e a r - o l d yap. 51 PlnuR R trn b u s 20' A cer ru b ru n A cer saccharum 20 DBH (cm) Age (yr) Fi g . 13. D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 tn in h e i g h t ) and DBH ( i n d i v i d u a l s > 1 .5 m in h e i g h t ) of t h e t h r e e m a jo r s p e c i e s found in a 9 0 - y e a r - o l d gap. 1* 0 P ln u s scriihuR - 30 20 10- 50 A cer rubrrnn 50 30 20 10 • 15 A cer saccharum 50 50 1*0 30 20 - 10 . i I lo Age 1*2 lu 16 18 i 10 15 20 25 30 DBH (cm) 35 **0 1*5 50 F i g . 14. D i s t r i b u t i o n o f age ( i n d i v i d u a l s <1.5 m i n h e i g h t ) and DBH ( i n d i v i d u a l s >1.5 m i n h e i g h t ) o f the t h r e e major species found i n 1 0 0 - y e a r - o l d gap. 52 i l l u s t r a t e d in t h e f i g u r e s r e p r e s e n t i n g t h e 5 0 - , 6 3 - , and 9 0 - y e a r - o l d gaps (Figures 11-13). G r e a t e r th a n f o r t y p e r c e n t of t h e s e e d l i n g s were 1 and 2 y e a r s ol d w it h very few o l d e r s e e d l i n g s , i n d i c a t i n g high m o r t a l i t y of young s e e d l i n g s , e s p e c i a l l y among w h it e p i n e . s e e d l i n g s in t h e 9 0 - y e a r - o l d gap were a l l (Figure 13). In a d d i t i o n , s u g a r maple in t h e y o u n g e s t age c a t e g o r y The d i s t r i b u t i o n f o r red and s u g a r maple s h i f t s t o l a r g e r s i z e c a t e g o r i e s as a r e s u l t of a few i n d i v i d u a l s s u r v i v i n g t o f i l l canopy gap as i l l u s t r a t e d in F i g u r e 12. in t h e S i m i l a r l y , S t e a r n s (1950) d e s c r i b e d a v i r g i n w hit e pi ne f o r e s t and found s u g a r maple g r a d u a l l y g a i n i n g in i m p o r t a n c e . The 1 0 0 - y e a r - o l d gap had a g r e a t e r p e r c e n t a g e o f s e e d l i n g s s u r v i v i n g t o t h e 6-8 and 1 0 - y e a r - o l d age c a t e g o r i e s be cause s e v e r a l l a r g e red and s u g a r maples blew o v e r f i v e y e a r s p r e v i o u s t o t h e study. This r e s u l t e d in a second g e n e r a t i o n gap and a second f l u s h of s e e d l i n g growth ( F i g u r e 1 4) . Survivorship. O v e ra l l m o r t a l i t y a p p ea re d t o be g r e a t e s t among y o u n g e s t s e e d l i n g s both i n t h i s s t u d y and o t h e r s (Bormann and Buell 1964, H e tt 1971, Good and Good 1972, Mulcahy 1 9 7 5) . A l a c k of w h i t e p in e r e g e n e r a t i o n was e v i d e n t from t h e 100% m o r t a l i t y a f t e r 18 y e a r s , s i m i l a r t o o t h e r old growth s t a n d s ( K i t t r e d g e 1934, Maissurow 1935, 1941, Lutz 1930, Morey 1936, and Smith 1940 ). Second growth w h i t e p i n e o c c u r s o nl y where t h e o ld growth s t a n d i s open (Ahlgren 1976). This i s s u p p o r t e d by F r o t h i n g h a m 's (1914) c o n c l u s i o n s t h a t o n l y 5.5% o f w h i t e p i n e s e e d l i n g s s u r v i v e d t o f o u r y e a r s unde r den se crown c o v e r , 60.8% s u r v i v e d under broken crown c o v e r and 94.0% s u r v i v e d in t h e open. Hartwick Pines p ro b a b ly o r i g i n a t e d f o l l o w i n g a st or m t h a t l e f t t h e a r e a open with only a few seed t r e e s (Wackerman 1924). Lutz and McComb (1935) a l s o found t h a t w h i t e pi ne o f a n o t h e r v i r g i n s t a n d o r i g i n a t e d und er a p a r t i a l canopy. It 53 was s u g g e s t e d by Bormann and Graham (1959) t h a t r o o t g r a f t s with dominant t r e e s may a s s i s t s e e d l i n g s and s a p l i n g s or may a i d i n r e s i s t a n c e t o windthrow. However, t o be an e f f e c t i v e a i d in m a i n t a i n i n g w h i t e pin e dominance, s e e d l i n g s must s u r v i v e long enough t o e s t a b l i s h a r o o t system w it h g r a f t s . S e v e ra l w h i t e p i n e s e e d l i n g s o f d i f f e r e n t ages were sampled a t Hartwick and no r o o t g r a f t s were o b s e r v e d . Sugar maple had t h e h i g h e s t s u r v i v o r s h i p v a l u e among s e e d l i n g s in gaps and un de r t h e f o r e s t canopy (T a b le 11 ), s u p p o r t i n g t h e c o n c l u s i o n s drawn from t h e age d i s t r i b u t i o n s . C o n tr a ry t o what was c o n cl ud e d from t h e age d i s t r i b u t i o n s , re d maple had t h e lo w e s t s u r v i v a l r a t e in t h e gaps w h i l e w hit e pin e had t h e lo w e st v a l u e under t h e f o r e s t canopy. However, t o a t t a i n H a r t w i c k ' s age d i s t r i b u t i o n s , a few red maple presumably s u r v i v e d whereas a l l o l d e r w h it e p i n e s e e d l i n g s presumably d i e d . In a d d i t i o n , t h e s u r v i v o r s h i p stucty of t h e t a g g e d s e e d l i n g s shows t h a t s e e d l i n g m o r t a l i t y was a t a minimum in t h e w i n t e r (T a b le 1 1 ) , p ro b a b l y due t o s e e d l i n g dormancy. Extreme c o l d and d e s i c c a t i o n were not problems f o r t h e s e s e e d l i n g s be ca u s e of t h e p r o t e c t i o n a f f o r d e d by snow cover. O v e r a l l , s u r v i v o r s h i p was lower un de r t h e canopy w h i l e n a t a l i t y was s i m i l a r f o r both t h e canopy and t h e gap, with s u g a r and r e d maple combined ha vin g a n a t a l i t y of 1 . 3 / m 2 / y r in t h e gaps and 1 . 5 / m 2 / y r under t h e canopy. During f a l l , 1979, o v e r a l l n a t a l i t y f o r w h i t e p i n e and hemlock combined was 11. 25 /m 2, in p a r t a r e s u l t o f t h e p r o l i f i c seed p r o d u c t i o n o f w h it e p i n e t h a t o c c u r s e v e r y t h r e e t o f i v e y e a r s (Harlow and H a r r a r 1968). The l a r g e number o f se e ds produced may he lp compensate f o r t h e l a r g e l o s s of seed t o red s q u i r r e l s ( T a m ia s c iu r u s h u d s o n i c u s ) . None o f t h e new c o n i f e r s e e d l i n g s s u r v i v e d t o t h e f o l l o w i n g s p r i n g , bu t be cause t h e y c ou ld not be i d e n t i f i e d t o d e t e r m i n e t h e p r o p o r t i o n o f w h i t e p i n e , 54 Tabl e 11. P e r c e n t s u r v i v o r s h i p of d i f f e r e n t aged s e e d l i n g s combined over one y e a r ( f a l l , 1977, t o f a l l , 1978) in r e l a t i o n t o s e a s o n and brow si ng, n = number of s e e d l i n g s a t s t a r t o f o b s e r v a t i o n . T ot al Wi n t e r Summer Browsed Unbrowsed Pinus s t r o b u s Canopy Forest Gap Canopy n % n i Acer saccharum Canopy Forest Gap Canopy n % n % 95 41 25 44 86.3 98 .9 87 .2 80.0 54.5 7 28.6 57.1 50.0 26 33 90 .2 9 7.6 92.5 9 6 .2 93.9 25 76.0 92 .0 82.6 Acer rubrum Canopy Forest Gap Canopy n % n % 235 69 72 79.6 92.8 85.8 7 6 .8 79.2 98 58.2 8 8 .8 65.5 55 th e y were not i n c l u d e d in t h e s u r v i v o r s h i p c a l c u l a t i o n s (T a b l e 1 1 ) . This would have d e c r e a s e d t h e s u r v i v o r s h i p v a lu e s f o r w h it e p i n e t o a l e v e l l e s s t h a n t h a t f o r red maple. Mechanical damage i s t h e s u s p e c t e d c a u s e f o r t h e 100% m o r t a l i t y of recently-germ inated c o n ife r seed lin g s. Leaf f a l l from maple and beech t r e e s c over ed t h e s u c c u l e n t w hit e p in e and hemlock s e e d l i n g s and, with t h e a d d i t i o n a l weight of r a i n and snow, c ru s h e d them. M o r t a l i t y would not have been as s e v e r e with only c o n i f e r n e e d l e l i t t e r which does not as re a d ily blanket a s e e d lin g . a r e a s with l e s s l i t t e r . Thus, w h it e p i n e w i l l e s t a b l i s h b e s t in open Thi s r e l a t i o n s h i p between hemlock m o r t a l i t y and t h e deci duo us l i t t e r f a l l i s d i f f i c u l t t o e x p l a i n beca us e i t i s o f t e n a common a s s o c i a t e of hardwoods. Maples, on t h e o t h e r hand, g e r m i n a t e in t h e s p r i n g and by f a l l a r e s i n g l e woody stems w i t h o u t b r a n c h e s , so l e a v e s la n d i n g on them t e n d t o s l i d e o f f o r a r e p i e r c e d , s u g g e s t i n g t h a t growth form might be an a d a p t a t i o n f o r s u r v i v a l unde r a b r o a d l e a f canopy. Environmental p a r a m e t e r s . There a ppea re d t o be a r e l a t i o n s h i p between t h e s e e d l i n g s p r e s e n t and t h e t e m p e r a t u r e and h um idi ty found i n t h e t h r e e st ud y a r e a s . The open a r e a where w h it e p in e were r e g e n e r a t i n g c o n s i s t e n t l y had t h e h i g h e s t daytime t e m p e r a t u r e s and t h e lo w e st hu mi dit y ( F i g u r e s 15 and 16 ). However, t h e s e e d l i n g s were p a r t i a l l y shaded in t h e a f t e r n o o n , p r o t e c t i n g them from high t e m p e r a t u r e s t h a t can produce s e e d l i n g m o r t a l i t y (Smith 1940). White p in e r e g e n e r a t i n g in p a r t i a l shade were a l s o obs er ve d in s e v e r a l o t h e r a r e a s , i n c l u d i n g t h e v i r g i n j a c k p i n e s t a n d t h a t was s t u d i e d . I f Hartwick was a r e s u l t of a few seed t r e e s t h a t were l e f t f o l l o w i n g a s to r m , as f i r s t propos ed by Wackerman ( 1 9 2 4 ) , th e n Hartwick to o o r i g i n a t e d in p a r t i a l shad e. In t h e gap, t e m p e r a t u r e s were between t h o s e found i n t h e r e g e n e r a t i o n a r e a and under t h e f o r e s t canopy. IQ A p ril 2 9 , 1978 F in e R e g e n e ra tio n Cap F o re s t O 0) 3 A p ril 10, 1978 — - ritte R e g e n e ra tio n -------------Gap —- - F o r e s t <0 CL to J u l y 2 ) , 1977 — — F in e R e g e n e ra tio n A ugust 1 . 1977 11 “ F in e R e g e n e ra tio n --C ap ------------ F b re s t To— n— i r T "To IT — Cap ■ F b re s t T am Time Fig. 15. Air te m pe ratu re in t h e t h r e e a r e a s during two days in th e s p r i n g and two days in t h e summer. Legend: Pine Regeneration=open ar ea where white pine are r e g e n e r a t i n g . Gap=area under t h e gap in t h e canopy, For est =a rea under t h e f o r e s t canopy. pm 100 ,A . A p r il 2 9 , 1976 i ' ■« P ing ftrg r n e ra tIn n A p r il 10, 1976 ------------Gap ' Forest 50- 20. Time am Fi g . 16. R e l a t i v e humidity in t h e t h r e e a re as during two days in t h e s pri ng and two days in t h e summer. Legend: Pine Regeneration=open area where white pine are r e g e n e r a t i n g , Gap=area under t h e gap in th e canopy, For est =a rea under th e f o r e s t canopy. 58 Humidity was h i g h e s t , prob ab ly due t o t h e i n c r e a s e d s o l a r i n s o l a t i o n which i n c r e a s e d t e m p e r a t u r e and e v a p o t r a n s p i r a t i o n , w h i l e t h e f o r e s t a c t e d as a wind b r e a k . The amount o f s o l a r i n s o l a t i o n , by c o n t r o l l i n g t e m p e r a t u r e , h u m i d i t y , and p h o t o s y n t h e s i s , and t h e s p e c i e s d e gre e o f shade t o l e r a n c e a r e key f a c t o r s in s u r v i v a l and s u c c e s s i o n o f t r e e s p e c i e s (Burns 1920, S h i r l e y 1943, 1945). P hotosynthetic ra te s of i n t o l e r a n t species are higher than t o l e r a n t s p e c i e s a t both high and low l i g h t i n t e n s i t y (Bohning and B u r n s id e 1956, Grime 1965, Baker 1945, S h i r l e y 1 9 4 5 ). In g e n e r a l , however, l i g h t compen sa tion p o i n t s a r e h i g h e r f o r i n t o l e r a n t s p e c i e s b e ca u s e th e y have h i g h e r r e s p i r a t i o n r a t e s (B ak er 1945, S h i r l e y 1945, Loach 1967 ). E a s t e r n w h i t e p i n e i s an i n t o l e r a n t s p e c i e s , as i n d i c a t e d by i t s co mpensation v a lu e o f 5.8% o f f u l l and e a s t e r n hemlock, 4.7% (Burns 1923 ). l i g h t compared t o s u g a r m a p le , 2.1% Smith (1940) f ound t h a t a t l e a s t 20% o f f u l l s u n l i g h t was r e q u i r e d by w h i t e p i n e f o r s u r v i v a l i n t h e f i e l d . The amount of l i g h t in t h e canopy gap o f Hartwick P i n e s was a p p r o x i m a t e l y 12% o f t h e a v e r a g e d a i l y amount of l i g h t (488 g c a l / c m 2 ) a v a i l a b l e in t h e Midwest d u r i n g A pril and May ( R e i f s n y d e r and Lull 1965), not enough f o r t h e s u r v i v a l and p e r p e t u a t i o n o f w h it e p i n e . O verall, the to ta l amount of s o l a r en er gy r e a c h i n g t h e s e e d l i n g l a y e r on A p r i l 29 and 30, 1978, was 368.9 and 3 0 0. 8 g c a l / c m 2 , r e s p e c t i v e l y , i n t h e w h it e pin e r e g e n e r a t i o n a r e a , 6 4 . 2 and 5 7 .8 g c a l / c m 2 u nd e r t h e canopy g a p, and 4 4 .1 and 3 1 .0 g c a l / c m 2 un d e r t h e f o r e s t canopy. I t a p p ea re d t h a t t h e r e was i n s u f f i c i e n t l i g h t e ne rg y un de r t h e f o r e s t canopy t o s u p p o r t s u s t a i n e d growth o f any s e e d l i n g s . In t h e ga ps , s o l a r energy was a d e q u a t e t o i n s u r e growth and s u r v i v a l o f t h e m a p le s. In t h e l a r g e r open a r e a t h e r e was enough s o l a r i n p u t t o m a i n t a i n growth o f w h it e p i n e . 59 Deer b r o w s i n g . W h i t e - t a i l e d d e e r were having an i m p o r t a n t i n f l u e n c e on t h e s e e d l i n g s i n t h e v i r g i n s t a n d by browsing t h e a r e a d u r in g l a t e f a l l and w i n t e r when t o u r i s t t r a f f i c was low. The g r e a t e r p e r c e n t a g e of s ug ar maples b e in g browsed was p r o b a b l y r e l a t e d t o t h e i r l a r g e r crown c o v e r a r e a ( F i g u r e 7 ) , making them more v i s i b l e and a c c e s s i b l e . In a d d i t i o n , s u g a r and red maple a r e p r e f e r r e d by d e e r (Aldous 1939, P e t r i d e s 1941). White p i n e , on t h e o t h e r hand, was browsed l e a s t , r e f l e c t i n g t h e s e e d l i n g s small s i z e , low d e n s i t y and p r o t e c t i o n by a l a y e r o f snow d u r i n g t h e w i n t e r . S e e d l i n g s w i t h i n t h e gaps were browsed more t h a n t h o s e und er t h e canopy, p o s s i b l y be ca us e d e e r were a t t r a c t e d by t h e l a r g e r s t a t u r e and g r e a t e r abundance o f s e e d l i n g s . Unbrowsed s e e d l i n g s had a s i g n i f i c a n t l y g r e a t e r i n c r e a s e in h e i g h t and crown c o v e r a r e a between 1977 and 1978 compared t o browsed s e e d l i n g s ( T ab le 1 2 ) . There was no s i g n i f i c a n t d i f f e r e n c e in s h o o t growth between t h e two g r o u p s . G e n e r a l l y , t h e new l e a d i n g sh o ot o f t h e browsed s e e d l i n g s grew more t h a n t h e unbrowsed. However, b e c a u s e t h e browsed s e e d l i n g s had t o b e g i n growth o f a new l e a d s h o o t from an a x i l l a r y bud, a h e i g h t a d v a n ta g e was ga in ed by t h e unbrowsed s e e d l i n g s . S u r v i v o r s h i p o f w h i t e p i n e in t h e unbrowsed p l o t was l e s s t h a n t h o s e t h a t were in t h e browsed p l o t , p r ob a bly b e ca u s e of i n c r e a s e d c o m p e t i t i o n from t h e unbrowsed maples (T a b le 1 1 ) . Most o f t h e s e e d l i n g s u n d e r s t u d y were red and s u g a r maple and i t a p p e a r e d t h a t t h e i r m o r t a l i t y was not a f f e c t e d by b ro w s in g . However, i t i s p o s s i b l e t h a t long te rm s e e d l i n g s u r v i v a l c o u ld be a f f e c t e d by t h e r e d u c t i o n in crown c o v e r or p h o to s y n ­ t h e t i c a r e a a nd , t h e r e f o r e , i n f l u e n c e t h e s u c c e s s i o n a l s t a t u s of t h e forest. In o t h e r s t u d i e s , c a t t l e g r a z i n g re duc ed t h e abundance o f hemlock and b e e c h , w h i l e almos t e l i m i n a t i n g red maple; and browsing by bi g game Ta bl e 12. S t u d e n t ' s t - t e s t comparison o f t h e e f f e c t of d e e r browsing over one y e a r on t h e h e i g h t , crown c o v er and shoot growth o f Acer saccharum and Acer rubrum combined. Mean I n c r e a s e i n Height cm n Mean I n c r e a s e i n Crown Cover cm^ Mean Shoot Growth n cm n Unbrowsed 5.7 86 186.0 77 3.4 4 174 Browsed 1.9 76 46.1 77 3.88 144 Significance .005 a NS = Not s i g n i f i c a n t . .005 NSa 61 an imals on b i t t e r brush in Idaho i n c r e a s e d twig p r o d u c t i o n and, at t h e same t i m e , r e t a r d e d s u c c e s s i o n (L u t z 1930, Peek e t a l . 1978). A long te rm s t u d y of t h i s q u e s t i o n would most l i k e l y show t h a t t h e maples a re be ing d e la y e d from assuming dominance in t h e gaps and u l t i m a t e l y t h e f o r e s t by t h e reduced growth or p o s s i b l e reduced s u r v i v o r s h i p . White p i n e r e g e n e r a t i o n . In t h e v i r g i n j a c k p i n e f o r e s t ne ar Hartwick P i n e s , w hit e p i n e s e e d l i n g s dominated t h e ground l a y e r , s u g g e s t i n g t h a t j a c k p i n e in t h i s c a s e i s a s e r a i s t a g e p r e c e d i n g w h i t e pine. Jac k pin e dominated t h e open canopy with a crown co ver a re a of a p p r o x i m a t e l y 2200 m2/ha. In 1977 t h e j a c k p i n e , with an a v er ag e age o f 62 y e a r s and range o f 39 t o 85 y e a r s o l d , were s e n e s c i n g with only 65% o f t h e 749 s t e m s / h a l i v i n g (Table 13 ). White p i n e and balsam f i r were a p p r o x i m a t e l y t h e same age and s i z e , and dominated t h e s e e d l i n g s t r a t u m w it h d e n s i t i e s o f 1710 and 1 5 0 /h a , r e s p e c t i v e l y . There were a l s o s o l i t a r y i n d i v i d u a l s of bla ck oak ( Quercus v e l u t i n a ) , bla ck c h e r r y ( Prunus s e r o t i n a ) and re d maple. Age d i s t r i b u t i o n s showed t h a t t h e r e were no young j a c k p i n e , i n d i c a t i n g i t s f a i l u r e t o r e p r o d u c e . p i n e s t a r t e d s e e d i n g - i n ab o ut tw e nty y e a r s ago and was s t i l l White coming i n , but a t a reduced r a t e ( F i g u r e 1 7 ) . Height and d i a m e t e r d i s t r i b u t i o n o f t h e v i r g i n w h it e p in e s t a n d n e a r D u b li n , Michigan, shows t h a t w h it e p i n e has t h e a b i l i t y t o come in un de r i t s own canopy under c e r t a i n c o n d i t i o n s ( F i g u r e 18 ). White pi ne was t h e most dense canopy s p e c i e s , w i t h 510 t r e e s / h a , 60% o f which were l e s s t h a n 10 cm in DBH and 10 m in h e i g h t ( F i g u r e 18 and T a b le 14 ). Maples had t h e ne xt g r e a t e s t d e n s i t y , w i t h 140 t r e e s / h a whereas b a s a l a r e a was 4 .8 5 m^/ha, compared t o 32. 75 m^/ha f o r w h it e pin e (T abl e 1 4) . Maple and w h it e oak i n d i v i d u a l s were s c a t t e r e d th r o u g h o u t t h e l a r g e r and s m a l l e r Table 13. Mean (+2 S.D.) age, h e i g h t , crown cov er, and basal diameter of woody s p ec ie s found in t h e v i r g i n Pinus Fanksiana Lamb, st a n d . Hei ght m Crown Cover m*n Age years n Pinus banksiana 62+10 26 Pinus s t r o b u s 11+5 223 1.22+0.73 223 .56+1.17 223 Abies balsamea 11+6 20 1.36+1.39 20 .48+0.15 20 Spec ies 21+5 n 73 4.5+2.4 73 Basal Diameter cm n 21.6+7.4 73 20 ■ \ IB 16- \ of Total \ \ * \ \ * \ \ \K \ \ * \ R \ \ k \ \ k* \ \ \ \ k \ k* \ *k \ k \ \ \ \ K \ \ \ \ *\ \ \ N \ \ \ \ $ - \ 10- Percent N \ Ib - 12 \ Pinus banksiana Pinus strobus \ \ 8 N K 6b- \ 2a \ \ 10 14 V 18 22 it V h 40 48 56 60 64 68 72 76’ '8 0 Age (Years) Fig. 17. Age d i s t r i b u t i o n oi Pinus banks i a n a and £ i n u s s t r o b u s in a v i r g i n Pinus b a n k s i ana s ta n d . M 88 64 A c e r sp p . P in u s s t r o b u s 7060 50 bo 50 Mean DBH=19.2 ± 2 1 .3 n=102 20 • Mean DBH= l4 .6 ± ?.>U n=52 — —— : 10' — 1 H — ■— i— i— i— i— i— i— i— i— i P in u s r e s l n o s a C u e rc u s a l b a 70 60 50 b0 of Total Percent n=10 n=19 20 10 Mean DBHrbl.O ± 2 .b 2 Mean DBH=25.b ± 1 5 .3 9 30 C-Tfl-ril-i 10 20 30 bo 50 -r-R 60 , 70 80 ' 10 ' ' ' 30 bO V to' 70 ' A) ' D ia m e te r a t B r e a s t H e ig h t (cm) A cer sp p . P in u s s t r o b u s 70 60 50 bo Mean H e lg h t= 1 2 .12 + 11.01 n=102 30 Mean H e lg h t= l8 .3 9 + 5*b5 n=28 20 10 . ■... P in u s r e s l n o s a ftu e rc u s a l b a 70 60 50 bo Mean H e ig h t= 1 9 .6 l ± 9*02 30 n=19 20 10 U] 10 j d 20 _ io ^ bt> r w Mean H e ig h t= 2 3 .5 ± 3 .1 6 n=10 10 20 30 ' bo ' 50 Height (m) F ig . 13. D i s t r i b u t i o n o f t r e e d ia m e te r and h e ig h t by species i n t h e v i r g i n stand near D u b lin , M ich ig a n . I Table 14. Importance v a lu e s 3 ( I - V . ) f o r t r e e s p e c ie s found in a 2 h e c t a r e v i r g i n Pinus s tr o b u s L. stand in Manistee Co., Michigan. I.V. Rank 1 2 3 4 5 6 7 8 Species Pinus st ro b u s Acer spp. Quercus al ba Pinus r e s i n o s a Prunus s e r o t i n a Fraxinus sp. Fagus g r a n d i f o l i a Pyrus malus Total Deni s t y Absolute Relative 510 140 95 50 25 10 15 5 850 60.0 16.5 11.2 5.9 2.9 1.2 1.8 0.6 100.1 Domi nance Absolute Relative 32.75 4.85 6.40 6.62 0.35 0.10 0.02 0.01 51.10 Frequency Absolute R e l a ti v e 64.1 9.5 12.5 13.0 0.7 0.2 0 .0 0.0 100.0 C a l c u l a t e d fo ll o w i n g methods in Mueller-Dombois and El le n b u r g (1974). 1.0 0.6 0.8 0.8 0.4 0.1 0.1 0.1 3.9 25.6 15.4 20.5 20.5 10.3 2.6 2.6 2.6 100.1 I.V. 149.7 41.4 44.2 39.4 13.9 4.0 4.4 3.2 300.2 I.V. 49.9 13.8 14.7 13.1 4.6 1.3 1.5 1.1 100.0 % 66 s i z e c l a s s e s , an i n d i c a t i o n t h a t th e y a r e r e p r o d u c i n g and s u r v i v i n g . S i m i l a r t o H a rt w ic k , t h e r e was no s i g n o f re d p in e r e p r o d u c t i o n . Although one of t h e l a r g e r w hi te p i n e t r e e s a t t h e M a n is te e County s i t e was o n l y 97 y e a r s o l d , t h e r e i s no i n d i c a t i o n o f lumbering a c t i v i t y ; and mounds i n d i c a t e t h a t t r e e s have f a l l e n i n p l a c e . This s u p p o r t s t h e a s s e r t i o n t h a t t h i s a r e a was r e l a t i v e l y u n d i s t u r b e d by humans. Un lik e H a r tw ic k , t h i s s t a n d had an open canopy which produced w h it e p i n e with l a r g e d i a m e t e r s between 70 and 75 cm, h e i g h t s r a n g i n g t o 30 and 35 m, and branches w ithin 2 m of th e ground ( F i g u r e 18 ). The l a r g e s t maples were 30 t o 35 cm i n DBH, s u g g e s t i n g t h a t t h e y e s t a b l i s h e a r l y in v i r g i n w h i t e p i n e stands. These t r e e s can t h e n a c t as s eed t r e e s f o r f u t u r e gap s. The s u r r o u n d i n g a r e a was dry sandy u p l a n d , dominated by r e l a t i v e l y small s ec ond-g ro w th o a k s , which i n c r e a s e d t h e openness o f t h e small p i n e s t a n d be ca us e of edge a f f e c t , and a i d e d t h e r e g e n e r a t i o n o f w h i t e p i n e under i t s own canopy. O b s e r v a t i o n s of s i m i l a r s t a n d s by some e a r l y r e s e a r c h e r s c o u ld have l e a d t o t h e c o n c l u s i o n t h a t w h i t e p i n e was a c li m a x community type. K i t t r e d g e and C h i t t e n d e n (1929) a l s o obs er ved w h i t e and r e d pin e r e p r o d u c t i o n i n Michigan i n o ld growth p i n e f o r e s t op en ing s but th e y s p e c i f i e d n e i t h e r s i z e nor c au s e o f t h e o p e n i n g s . In a v i r g i n re d pin e s t a n d s c a t t e r e d w it h l a r g e w h it e p i n e , S h i r l e y (1932) found w h i t e p in e r e g e n e r a t i n g in a 2929 m2 o p e n in g , t w e n t y - s i x ti m e s t h e s i z e o f t h e mean structural gap opening a t H a rt w ic k . White p i n e r e g e n e r a t i o n d i d not o c c u r a t Hartwick in op en ing s as small as 89 m2 o r 135 m2 , as o b s er v ed f o r l o b l o l l y and s h o r t l e a f p i n e ( Pinus t a e d a and Pinus e c h i n a t a ) (Wahlenburg 1948, J a c k s o n 1959). 67 S u c c e s s io n and Biomass Model Hartwick e x h i b i t e d s u c c e s s i o n as a r e s u l t of r e l a t e d changes in v e g e t a t i o n , s o i l s and m i c r o c l i m a t e ( a u t o g e n i c ) , and as induced by changes i n t h e e x t r i n s i c en vironment ( a l l o g e n i c ) . A p p a r e n t l y w hit e p in e canopy development p r e v e n t e d some s p e c i e s from s u r v i v i n g , w h il e g a p s, caused by e x t e r n a l f a c t o r s , were i n s u r i n g t h e s u r v i v a l of o t h e r s . More s t u d i e s a re c o n c l u d i n g t h a t development of f o r e s t c o m p o s i ti o n and s t r u c t u r e i s a r e s u l t o f l a r g e and small s c a l e d i s t u r b a n c e s , and small gaps and dominant t r e e s modif yin g t h e e n vi ro nm e n t (Fox 1977, O l i v e r and S te p h e n s 1977 ), as ob s er ve d a t Hartwick P i n e s . Evidence from t h i s st udy s u g g e s t s t h a t , g iv e n an a p p r o p r i a t e seed s o u r c e , one s u c c e s s i o n a l seq uence f o r t h e Hartwick a r e a s t a r t s with j a c k pine following a r e l a t i v e l y large s c a le d istu rb a n ce . J ac k p in e w il l p o s s i b l y dominate t h e f o r e s t u n t i l t h e y s e n e s c e a t a b o u t 6 0- 80 y e a r s o f age ( F i g u r e 1 9 ) . In t h e a bse nc e o f any f u r t h e r r e l a t i v e l y Targe s c a l e d i s t u r b a n c e , w h it e p i n e and t h e n hardwoods may dominate t h e f o r e s t . White p i n e may invad e and hold dominance as a pure s t a n d f o r a p p r o x i m a t e l y 170 years. A t r a n s i t i o n t o a hardwood f o r e s t dominated by maples i s l i k e l y t o f o l l o w , as i s p r e s e n t l y o c c u r r i n g i n Hartwick P i n e s . During t h i s p e r i o d w h i t e p i n e may remain a c o n s p ic u o u s p a r t o f t h e f o r e s t f o r as long as 200 years. The amount of ti m e f o r t h i s t r a n s i t i o n was d e t e r m i n e d , not by t h e p r e s e n t r a t e of d e a t h and canopy re p la c e m e n t a t Hartwick ( o n l y 6 % o f t h e to tal sample a r e a in t h e l a s t 10 y e a r s ) , bu t was based on t h e r e p o r t e d maximum ages o f w h i t e p i n e . This s u g g e s t s an i n c r e a s e in t h e r a t e of r e p la c e m e n t a t Hartwick ove r t h e next c e n t u r y . A f t e r t h i s , hemlocks and hardwoods would p ro b a b l y s h a r e dominance f o r 200 y e a r s with p e rh a p s a gradual s h i f t t o ma ple -beech dominance. Thi s f o r e s t would have t h e to M at 3 oo w (J (0 (0 r l iJ O x> CO (0 B -h Biomass (m t/h a ) WO o co 5 Jack P ine Wliite Pine Pine Hemlock Hardwood I ' Hemlock Hardwood Hardwood Jack White P ine Time (y r) Fi g. 19. Hypothetical s e r a i s t a g e s in an area of c e n t r a l n o rt h e rn lower Michigan i n d i c a t i n g changes in biomass and t h e in f l u e n c e of d i s t u r b a n c e . 69 a b i l i t y t o re p ro d u c e and m a i n t a i n i t s e l f as an old growth v i r g i n f o r e s t , and i n t h e c a s e o f Hartwick P i n e s , more a p p r o p r i a t e l y be named Hartwick Hardwood S t a t e P a rk . Rec ogniz ing t h e l i m i t a t i o n s o f making co mparisons between s t a n d s in d i f f e r e n t c l i m a t i c r e g i o n s , growing on d i f f e r e n t s u b s t r a t e and c o n s i s t i n g perh ap s of d i f f e r e n t g e n e t i c s to c k t h e r e i s rea son t o b e l i e v e t h a t d u r in g t h i s s u c c e s s i o n a l sequ en ce biomass peaks and t h e n a c t u a l l y d e c r e a s e s in the la te stages. Biomass i n c r e a s e s from t h e maximum j a c k pine biomass ( 8 5 . 4 m t / h a , La rse n 1982) t o a peak when w h it e p i n e domin ate s (681 m t/ h a ) and as t h e hardwoods assume dominance, biomass pro ba b ly d e c r e a s e s (515 m t / h a , Murphy, P . G . , and G. Kroh, Biomass and Net Primary P r o d u c ti o n of a V i r g i n Beech-Maple F o r e s t in Mi chigan, in p r e p a r a t i o n ) (Figure 19). This i n d i c a t e s t h a t biomass may not always i n c r e a s e t o a maximum a t t h e c lim a x s t a g e as Odum (1969) had s u g g e s t e d . The ba sal a r e a o f t h e beech-maple s t a n d i s 41% l e s s t h a n t h e whit e p i n e s t a n d , which p ro b a b l y a c c o u n t s f o r t h e d e c r e a s e in bio m a s s. The d e c r e a s e s may be a r e s u l t of t h e way each t y p e o f s t a n d i s e s t a b l i s h e d and mai n t a i n e d . S e l f - r e g e n e r a t i n g be ech-m aple f o r e s t s n a t u r a l l y c o n s i s t o f small d i s t u r b a n c e op e n in g s w it h young small t r e e s t h a t c o n t r i b u t e l i t t l e t o t h e total l i v i n g bioma ss. Taking i n t o account t h e s e small d i s t u r b a n c e o p e n i n g s , long t e r m biomass e q u i l i b r i u m in t o l e r a n t beech-maple f o r e s t s can s t i l l be e s t a b l i s h e d in r e l a t i v e l y small a r e a s . White pi ne e s t a b l i s h e s as a r e l a t i v e l y even age s t a n d t h a t grows u n t i l t h e s i t e i s f u l l y o c cu pie d by a n e a r maximum s u s t a i n a b l e biom ass. During t h i s phase l i t t e r p r o d u c t i o n i s b a l a n c e d by new gro w th, c r e a t i n g a r e l a t i v e l y s h o r t t e r m biomass e q u i l i b r i u m . Tr ee d e a t h s c a u s i n g small canopy openings 70 r e s u l t In a d e c r e a s e i n biomass with beech-maple e s t a b l i s h i n g in gaps. Long te rm biomass f o r w h i t e p i n e f o r e s t s can be e s t a b l i s h e d i f t h e r e i s enough a r e a t o i n c l u d e t h e r e l a t i v e l y l a r g e d i s t u r b a n c e op en ing s t h a t a r e n e c e s s a r y f o r t h e r e g e n e r a t i o n of w h it e p i n e . This s i t u a t i o n r e s u l t s i n w h i t e p i n e s ' lo n g t e r m biomass e q u i l i b r i u m b e in g l e s s t h a n t h e s h o r t te rm equilibrium . As t h e s i z e of t h e d i s t u r b a n c e t h a t i s n e c e s s a r y t o p e r p e t u a t e t h e f o r e s t t y p e i n c r e a s e s , p r o p o r t i o n a t e l y more a r e a i s needed t o e s t a b l i s h biomass e q u i l i b r i u m ( S h u g a r t and West 198 1) . F u rth er study i s r e q u i r e d t o d e t e r m i n e t h e maximum biomass of an a r e a l a r g e enough t o s u p p o r t w h i t e p i n e as a r e g e n e r a t i n g dominant. In a p r i m i t i v e s e t t i n g , l e s s i n f l u e n c e d by humans, s e v e r a l d i f f e r e n t s t a b l e communities c ou ld e x i s t a d j a c e n t t o each o t h e r as a r e s u l t o f only d i f f e r e n c e s in s i z e , f r e q u e n c y and t y p e of d i s t u r b a n c e in an o t h e r w i s e unifo rm en vi ro nme nt (Horn 197 6) . F i r e and wind a r e t h e two pre dominant n a t u r a l d i s t u r b a n c e s , with f i r e bei ng t h e most common l a r g e - s c a l e d i s t u r ­ bance t h a t would a l l o w p i n e t o r e g e n e r a t e . Based on t h e h y p o t h e s i z e d s u c c e s s i o n ti m e s c a l e , a very d e s t r u c t i v e f i r e with a f r e q u e n c y of 300-400 y e a r s c oul d r e s u l t in w h i t e p i n e c o n t i n u a l l y r e g e n e r a t i n g i t s e l f , p o s s i b l y pre ced ed by j a c k p in e o r a l i g h t seeded hardwood de pending on t h e a v a i l a b l e see d s o u r c e ( F i g u r e 1 9 ) . F o r c i e r (1975) documented a m i c r o s u c c e s s i o n a l p a t t e r n f o l l o w i n g a minor d i s t u r b a n c e i n a c li m a x f o r e s t h e l p i n g t o i n s u r e c o n t i n u e d c o - o c c u r r e n c e o f y e l l o w b i r c h , s u g a r maple and beech. On t h e o t h e r hand, Brewer and M e r r i t t (1978) c o n c lu d e d t h a t windthrow of s i n g l e t r e e s would only p e r p e t u a t e beech in a be ech-m aple f o r e s t and t h a t t h e d i v e r s i t y would have t o be m a i n t a i n e d th ro u g h l a r g e r disturbances. Depending on t h e t y p e o f community, d i v e r s i t y can a l s o be m a i n t a i n e d by a c e r t a i n f r e q u e n c y o f d i s t u r b a n c e . S m a l l e r ground f i r e s 71 c o u ld a l s o a i d in p e r p e t u a t i n g w h i t e pin e by removing l i t t e r and hardwood seedling com petition. I f , in a d d i t i o n , a f i r e had opened a l a r g e enough a r e a in t h e canopy and t h e re m a in in g p in e t r e e s had a good s ee d y e a r , w h i t e p i n e would r e g e n e r a t e . I f t h i s c y c l e were c o n t i n u a l l y r e p e a t e d , w h i t e p i n e c o u ld m a i n t a i n i t s e l f as t h e dominant t r e e i n d e f i n i t e l y . P o s s i b l y f o r t h e s e r e a s o n s , w h it e p i n e was a ma jor dominant o r end p o i n t o f s u c c e s s i o n in l a r g e a r e a s p r i o r t o l um be ri ng, even though i t may now be viewed as a m i d - s u c c e s s i o n a l s p e c i e s . SUMMARY AND CONCLUSIONS E a s t e r n w h it e p i n e a t Hartwick P in e s S t a t e Pa rk , which a v e r a g e d 177 y e a r s in a g e , was t h e canopy dominant with a basa l a r e a o f 4 8 . 4 m2/ h a , 66.7% o f t h e t o t a l . I t s a v e r a g e d i a m e t e r and t o t a l h e i g h t were 58 cm and 36 m, r e s p e c t i v e l y . White p in e and hemlock d i a m e t e r d i s t r i b u t i o n s i n d i c a t e t h a t t h e l a r g e s t t r e e s may be r e l i c s from a d i s t u r b a n c e , and t h a t t h e s e t r e e s p o s s i b l y a c t e d as a s eed s o u r c e f o r most of t h e p r e s e n t i n d iv id u a ls in th e f o r e s t . At t h e p r e s e n t ti m e t h e p r im a r y c aus e of d e a t h o f w h it e p i n e a p p e a r s t o be w i n d f a l l . H e ar t r o t t h a t i n i t i a t e d from 134 y e a r - o l d f i r e s c a r s was a c o n t r i b u t i n g f a c t o r t o t h e d e a t h of some of t h e t r e e s . Thi s s t a n d had a t o t a l t r e e biomass o f 681 m t / h a , above a v e r a g e f o r many o f t h e worlds f o r e s t t y p e s . To tal ne t pr im ar y p r o d u c t i o n of t h e s t a n d was low, 7 . 5 m t / h a / y r , b u t w i t h i n t h e range of f i g u r e s r e p o r t e d f o r temperate evergreen f o r e s t s . A d d i t i o n a l n o n d e s t r u c t i v e s t u d i e s o f w h it e p i n e biomass and p r o d u c t i o n w i l l be a i d e d by t h e a l l o m e t r i c e q u a t i o n r e l a t i n g w h i t e p in e d i a m e t e r and stem volume ( r 2 = 0 . 9 1 ) . Diam et er and h e i g h t c l a s s d i s t r i b u t i o n s i n d i c a t e t h a t s u g a r m a pl e , r e d maple and beech a r e g r a d u a l l y assuming dominance. Among s e e d l i n g s , red ma ple, be cause of i t s l a r g e numbers, had t h e h i g h e s t im por ta nc e value. I n d i v i d u a l s u g a r maple s e e d l i n g s had t h e l a r g e s t crowns, r e f l e c t e d by t h e i r g r e a t e r s h o o t grow th. e v e n t u a l dominance by m a p le s. These f a c t o r s c o n t r i b u t e d t o White p in e s e e d l i n g s were as numerous as 72 73 s u g a r maple, bu t grew p o o r l y . Beech s e e d l i n g s were not p r e s e n t in t h e s t u d y p l o t s and o n ly a few were o b s e r v e d in t h e f o r e s t . Only maples s u r v i v e d p a s t t h e s e e d l i n g s t a g e and a f t e r a p p r o x i m a t e l y 50 y e a r s f i l l e d in canopy ga ps. A s s o c i a t e d wit h t h e c l o s i n g of canopy gaps was a d e c r e a s e in s e e d l i n g a v e r a g e a g e , h e i g h t , b a s a l d i a m e t e r , crown c o v e r , sh oo t growth and p e r c e n t a g e o f s e e d l i n g s browsed by d e e r . Sugar maple was l e a s t a f f e c t e d by gap c l o s u r e ; however, t h e s e s e e d l i n g s d i d not do as well under a maple canopy as compared t o a p i n e canopy or gap. S u r v i v o r s h i p was g r e a t e s t f o r s e e d l i n g s in g a p s, as compared t o t h e f o r e s t , and d u r i n g w i n t e r as compared t o t h e growing s e a s o n . Sugar maple in gaps had t h e l a r g e s t annual s u r v i v o r s h i p , 90.2%, whereas red maple was lo w e st a t 79.6%. N a t a l i t y f o r maples was 1 . 3 / m 2 / y r in t h e gap and 1 . 5 / m 2 / y r under t h e canopy. White p in e and hemlock combined n a t a l i t y was 1 1 . 2 5 / m 2 / y r d u r i n g a y e a r o f high s eed p r o d u c t i o n , b u t with 100% m o r t a l i t y p o s s i b l y due t o mechanical damage from l e a f l i t t e r and snow. comparison was made o f s e e d l i n g dynamics in t h r e e s i t u a t i o n s : A w ithin a canopy gap, un de r t h e f o r e s t cano py, and in an open a r e a of w h it e p i n e regeneration. The w h i t e p i n e r e g e n e r a t i o n s i t e had t h e lo w e st h u m id ity and h i g h e s t a i r t e m p e r a t u r e and s o l a r i n s o l a t i o n , t h e l a t t e r f a c t o r b e in g one of t h e most i n f l u e n t i a l f a c t o r s in t h e s u r v i v a l o f w h it e p i n e . Under some c i r c u m s t a n c e s where t h e canopy was s u f f i c i e n t l y open, w h i t e p in e were a b l e t o r e g e n e r a t e under both v i r g i n j a c k and w h it e p in e s t a n d s . Deer a p p e a r t o have r e t a r d e d t h e h y p o t h e s i z e d s u c c e s s i o n a l change a t Hartwick by ha vi ng browsed a high p e r c e n t a g e of s e e d l i n g s . Even though no d i f f e r e n c e s were found i n y e a r l y s h o o t growth l e n g t h between browsed and unbrowsed m a p le s , onl y maple s e e d l i n g s in e x c l o s u r e s had a s i g n i f i c a n t net i n c r e a s e in h e i g h t b e c a u s e t h e i r i n i t i a l h e i g h t had not been reduced by 74 brow si ng . There was a l s o a s i g n i f i c a n t i n c r e a s e in crown c o v er among t h e unbrowsed maple s e e d l i n g s which, a lo n g with t h e i n c r e a s e in a v e r a g e h e i g h t , c o u ld have r e s u l t e d in i n c r e a s e d c o m p e t i t i o n l e a d i n g t o d e c r e a s e d s u r v i v a l of w h i t e p i n e . A p o s s i b l e s u c c e s s i o n a l s e r i e s f o r t h i s gener al a r e a , i f u n i n t e r r u p t e d by f i r e , i s ja c k p i n e f o r t h e f i r s t 80 y e a r s , w h i t e p i n e f o r 170 y e a r s , w h it e p i n e and n o r t h e r n hardwoods f o r 200 y e a r s , hemlock n o r t h e r n hardwoods f o r 200 y e a r s with maple dominated n o r t h e r n hardwoods as a long te rm s t a b l e community. Biomass i n c r e a s e s t o a maximum when w h i t e p i n e a r e d o m in a tin g and d e c r e a s e s as t h e f o r e s t su cc e ed s t o hardwoods. F i r e has t h e a b i l i t y t o p r e v e n t hardwoods from assuming dominance; f o r example, a t Hartwick t h e age of t h e o l d e s t d e ci du ou s s p e c i e s c o r r e s p o n d s t o t h e tim e s i n c e t h e l a s t ground f i r e . Large f i r e s e v e r y 300-400 y e a r s would c y c l e t h e s u c c e s s i o n a l s e r i e s th r o u g h j a c k p i n e o r a l i g h t se e de d hardwood, dep end ing on t h e a v a i l a b l e see d s o u r c e , t o white pine. F i r e s of a medium s e v e r i t y e v e r y 200 y e a r s would e l i m i n a t e t h e hardwoods and open l a r g e enough gaps f o r r e g e n e r a t i o n of w hi te pine indefinitely. FOR FURTHER STUDY C e r t a i n i s s u e s r e g a r d i n g t h e e c o lo g y o f w h it e p in e f o r e s t s remain unclear. I pro po s e t h a t t h e f o l l o w i n g q u e s t i o n s a re among t h e most deserving of f u r t h e r a t t e n t i o n . 1. What is t h e s i g n i f i c a n c e of t h e r e l a t i v e l y low w hit e pine l e a f biomass? Does t h e change in p r o p o r t i o n of l e a f biomass t o t o t a l t r e e biomass as t h e t r e e ages a f f e c t i t s s u r v i v a l ? 2. Is t o t a l f o r e s t o r g a n i c m a t t e r ( i n c l u d i n g d e t r i t u s ) g r e a t e r f o r s u c c e s s i o n a l s t a g e s f o l l o w i n g w h i t e pin e ? What a r e t h e long te rm biomass e q u i l i b r i u m v a l u e s f o r t h e s e r a i s t a g e s d e s c r i b e d in t h i s s t u d y ? What a r e t h e d i f f e r e n c e s i n s e r a i biomass changes between communities with and w it h o u t n a t u r a l l y o c c u r r i n g f i r e ? 3. What e f f e c t would t h e r e s u l t s o f a long te rm s t u d y of s u r v i v o r s h i p and d e e r browsing have on t h e c o n c l u s i o n made in t h i s s tu d y ? 4. What a cc o u n ts f o r t h e p r e s e n c e o f beech and hemlock given t h e small number o f s e e d l i n g s obser ved ? 5. Is mechanical damage r e s p o n s i b l e f o r 100% m o r t a l i t y of newly g e rm in a te d p i n e and hemlock? 6. Why does s u g a r maple a p p e a r t o e x h i b i t poor growth under a maple canopy? How w i l l t h i s answer i n f l u e n c e our u n d e r s t a n d i n g o f r e g e n e r a t i o n and gap phase re p la c e m e n t as r e l a t e d t o s u c c e s s i o n ? 75 LITERATURE CITED LITERATURE CITED 1. A hlg re n , C. E. 1976. R e g e n e r a t i o n of red pi ne and w h i t e pine f o l l o w i n g w i l d f i r e and l o g g i n g in n o r t h e a s t e r n Minneisota. J o u r n a l o f F o r e s t r y 7 4: 1 3 5 -1 4 0 . 2. Aldous, S. E. 1939. Pin e in t h e d i e t of w h i t e - t a i l e d d e e r . J o u r n a l o f F o r e s t r y 3 7 :2 6 5- 26 7. 3. A r t , H. W., and P. L. Marks. 1971. A summary t a b l e of biomass and ne t annual pri m ar y p r o d u c t i o n in f o r e s t e co sy st em s o f t h e w or ld . 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