HI TH _ AN L'VESWGAWON OF THE TOLERANCE 63F WHiTE ASH REPRQDUCTEN Thesis far fins; Swarm of M. S. Mfo'lKSA ‘3 E‘TA'TE CGLLE’SE huuefi ‘fir‘fayne Gueriflmr E‘QSG 0-169 Date 1 ' 1.3.2.- mm l < 'v s ‘ \ e 4 ‘ I . . | I .o 0-, e. a“ ‘— W This. is to certify that the . J'.’ 5‘. 1 “‘ thesis entitled An Investigation of the Tolerance of White Ash Reproduction presented by Kenneth lbyne Guenther has been accepted towards fulfillment of the requirements for degree mm ...-a L..- -__. u ‘1— n I I . I '1 O ,I 1 . J . ' A \ 5 ~ I I | V L 1 I I . l J 0 ."-," ‘ . ‘ , , ' ;,’§.’ a1,’~l 7/, . , I ‘r? " ' I“ ' 1 .,.'D.‘ '...- H. #:4 «a . x. ‘. _ s .‘~| J ' . ;,. .t x..-'.', " v. "_ j; '|""* J ‘ e "‘0' 9‘ ' ' e... t , "3' e‘ s -‘\ C ' .41., I Jf’V'. . ~' . "$17" ’ v, f ‘ '69..." so .. ‘39. ' I - (a I Q,‘ ‘ ' .: v . ‘ . .j* .V ' ‘ I- : .A g ‘ ‘ '3:."-v . ' ”1%. a,“ '7.“- d":1:'.! I |: .‘ ' ff '. \ r :31 r ' ‘4 ~.“.'*|n _- "9 - .‘ \('_ e D ‘ 'I'w‘ r't. }I(_D >‘i I I . “I...“ o ‘q’ ' ma" . l I ‘3 ‘A ' “J 1‘ IM'V‘ k ’ o . 3:. 1‘. ' ‘ -.' " K . \ ”J1 "" air. . V A. 2" § . s A‘;Q; _ A V ' ’. :7 t C. ‘;- e l ‘ ok :51» I . i‘r' \ I V . Q I ,- > - ‘If . C". c. I . ‘7 r' O ".1.- 3‘ o 3’. 91‘ , ‘ ‘ ' v .‘a, t ' 3‘ . '79; I 1 J, i - . --. J 1". _ _-‘ l ". r ~ ‘ 3:12, \ PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. DATE DUE DATE DUE DATE DUE JUN 15A 5. 'r MSU Is An Affirmative Action/Equal Opportunity Institution AN INVESTIGATION OF THE TOLERANCE 01“ WHITE ASH REPRODUCTION By KENNETH mm GUENTHEB w A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requiremente for the degree of MASTER OF SCIENCE Department of Forestry 1950 THESIS ACKNOWLEDGMENIS CONTENTS BOOKS Ilaikufiwnnflaflflhflflfibnfi Fran: Miss Lois E. Potter Moon Memorial Library State University of New York §1racuse lOLgNew York Chimummflxnkanx SW C] Express Prepaid Value $50 . POSTMASTER: THIe PARCEL MAY a: OPENED FOR POSTAL INSPECTION IF NECESSARY. 7b LIBRARY MICHIGAN STATE COLLEGE REFERENCE DEPARTMENT EAST LANSING, MICHIGAN . r . I‘ . , . . : .:" l, '- ‘2 ail-"Lav “.11).; ‘ LL': .'- :4 N-B‘Z era-INT :: rim .ded and encour— zel of the Mich- rblem and gave lgkins of the lance throughout K. Hudson of the editing. TH 5515 ACKNOWLENMFNTS The author is very grateful to those who have guided and encour- aged him in this investigation. Professor Leslie W. Gysel of the Mich- igan State College Forestry Department suggested the problem and gave invaluable assistance throughout. Professor Earl J. Hodgkins of the Michigan State College Forestry Department provided guidance throughout the deve10pment of the investigation. Professor Robert K. Hudson of the Michigan State College Forestry Department aided in the editing. TABLE OF CONTENTS PAGE INTRODUCTION......................... 1 REVIEWOFLITIRATURE..................... 2 PROCEDURE.......................... 6 FieldProcedure...................... 6 OfficeProcedure...................... 10 DISCUSSION.......................... 13 Effects of CanOpy Conditions and Age Class of Reproduction onVigor.......................... 13 Effect of Age of Reproduction on Vigor . . . . . . . . . . 13 Effect of Canopy Class on Vigor of Reproduction . . . . . 16 General Discussion of a Comparison of CanOpy Conditions . . 18 HeavyCanOpyConditions .................§ 18 Light CanOpy Conditions and Campy Openings . . . . . . . 20 SUMLIARI........................... 37 LITmATURECITED....................... 38 APPENDIX........................... 40 Description of Representative Plots . . . . . . . . . . . . 41 HeavyCanOpy....................... 1.1 LightCanoPy....................... 1.3 SmaJlCanOPyOpening................... 45 Large Canopy Openim O O O O O O O O O O O O O O O O O O O 47 LIST OF TABLES TABLE PAGE 1. Summary of division of plots, by canopy conditions and of division of white ash reproduction by age classes . l2 2. Summary of average annual height growth and average annual cumulative height growth of white ash repro- duction under heavy canOpy conditions (based on 12 plots) . . . . . . . . . . . . . . . . . . . . . . . . 22 3. Summary of average annual height growth and average annual cumulative height growth of white ash repro- duction under light canopy conditions (based on 8 plots) . . . . . . . . . . . . . . . . . . . . . . . . 23 4. Summary of average annual height growth and average annual cumulative height growth of white ash repro— duction under small canopy Openings (based on 3 plots) . . . . . . . . . . . . . . . . . . . . . . . . 24 5. Summary of average annual height growth and average annual cumulative height growth of white ash repro- duction under large canopy Openings (based on‘3 phmfl ... ... ... ... ... ... ... ... 24 6. Representative plot under heavy canopy, plot number 9. . 42 7. Representative plot under light can0py, plot number 17 . 1.4 8. Representative plot under small canOpy Opening, plot number 5 . . . . . . .1. . . . . . . . . . . . . . . . 46 9. Representative plot under large canOpy Opening, plot numberlZ...................... 48 LIST OF FIGURES FIGURES l. 2. 5. 6. 7. 8. 10. Average annual height growth per stem, of white ash reproduction under heavy canopy conditions . . . . . Average annual height growth per stem, of white ash reproduction under light canopy conditions . . . . . Average annual height growth per stem, of white ash reproduction under large canOpy Openings. . . . . . Average annual height growth per atom, of white ash reproduction in the l to 9 year age class under all canopy condition classes . . . . . . . . . . . . Average annual height growth per stem, of white ash reproduction in the 10 to 15 year age class under three canopy condition classes.. . . . . . . . . . . Average annual height growth per stem, of white ash reproduction in the lé-pluseyear age class under two canopy condition classes . . . . . . . . . . . . Average cumulative height growth per stem, of white ash reproduction under all canopy condition classes. Average cumulative height growth per stem, of white ash reproduction under three canopy condition classes . . . . . . . . . . . . . . . . . . . . . . Average cumulative height growth per stem, of white ash reproduction under two canopy condition classes. Average cumulative height growth per stem, of white ash reproduction under three canopy condition Class 88 O O O O O O O O I O O O O O O O O O O O O O 0 PAGE 25 26 27 28 30 31 32 33 34 FIGURE PAGE 11. Normal and actual monthly percentage of possible sun— shine compared to the average annual height growth per stem for the 10 to 15 year age class, under a light canopy during the period of from l944.to 1948 inclusive . . . . . . . . . . . . . . . . . . . . . . 35 12. Normal and actual monthly inches of precipitation com- pared to the average annual height growth per stem for the 10 to 15 year age class, under a light canOpy during the period of from 1944.to 1948 inclusive . . . 36 AN INVMIGATION OF THE TOLERANCE OF WHITE ASH REPRODUCTION By Kenneth Wayne Guenther INTRODUCTION The genus Fraxinus yields woods which are greatly desired for their physical pr0perties, such as, strength, hardness, stiffness, shock- resisting ability, absence of odor, and excellent bending qualities. Because of the deminishing amount of ash in the Central Hardwoods Re- gion, the center of production of this wood has shifted to Louisiana, Tennessee, and Georgia. 0f the ash genus, the species most abundant and important in the United States is the white ash (Fraxinus americana L.). White ash, a dioecious tree, occurs as a minor species in the beech—sugar maple forest type in the Central Hardwoods Region. Being tolerant in early life and less tolerant later, white ash reproduction decreases in its percentage representation in the stand with age, under normal all-aged forest conditions. It was an empirical observation of the author that white ash in the later sapling stagey is rarely found under dense canOpies. Under a high thin canOpy, however, or in Open- ings, the pole stageg/ can be reached. The purpose of this study was to ascertain specifically under what canOpy conditions ash reproduction will maintain its vigor and when it will not. 1/ The sapling stage is from 3 feet high to 4 inches diameter breast high (d.b.h.). _2_/ The pole stage is from 1. inches d.b.h. to 12 inches d.b.h. -1... REVIEW OF LIT ERATURE White ash is reported by Cape (4) to be not very exacting in its seedbed requirements. Sterrett (11), however, states that ash seed is esPecially dananding in its moisture requirements for germination and seedling establishment, but that a moderately Open seedbed is suffi- cient. An anemone British author (1) recommends that ash reproduc- tion should be attempted only on moist, fresh soils and that its asso— ciates should be encouraged on the drier sites. Tourney and Korstian (12) consider white ash reproduction as be— ing very exacting and as deteriorating rapidly when planted on sites where available moisture falls much below that required for Optimum growth. Feher (5) reports white ashes requiring '70 to '75 per cent of the water absorptive capacity-y of the soil for optimum growth. Sterrett (11) considers the genus Fraxinus as being less exacting on loose, fri- able soils than on tight soils. He further states that the genus is adapted for non-acid swamp conditions if grass competition is absent and the water is not stagnant. However, he reports white ash as toler- ating drier sites than most of the ashes. The division of. white ash into three ecotypeay has been suggest- ed by llright (15) after his study at the Harvard Forest Nursery. Seeds for the stuck were collected from throughout the botanical range of white ash. The northern ecotype found from Michigan to central Penn- sylvania and New England exhibited little wint er-kill, had a bushy root system, and showed a lack of pubescence and anthocyanin develOpment. g] Field capacity. 5/ The product arising as a result of the genotypical response of an ecospecies to a particular habitat. -2- The intermediate ecotype found in a narrow bolt through southern Penn- sylvania, northern West Virginia, and Ohio exhibited moderate wint a- kill, a bushy root system, and a high incidence of pubescence. The southern ecotype found in all rmaining southern regions exhibited heav- y winter-kill, had a tap root, and had leaves which were glossy above and pubescent underneath. Wright (15) believes that one of the Juven- ile characteristics of white ash is its inability to harden off prep- erly even in a climate to which its progenitors are native. Because of this characteristic, young white ash progresses va'y slowly until na- ture enough to withstand winta's unharmed. lhite ash sprouts successfully from young trees, according to Westveld (18). However, seedlings are the major method of regeneration. He also states that seedling sprouts made two to three times the growth of seedlings end-«suggests conversion of seedlings to seedling sprouts if feasible. " In North Carolina, Kramer (3) found that white ash seedlings made twice the shoot growth of red oak seedlings. Sterrett (11) reports that ash made practically all its growth by July and that it spurt the reminder of the normal growing season in hardening the current growth. Patton (10) found the heights of white ash reproduction unda' non- described canOpy conditions to be: 1.5, 3.0, 4.9, 6.5, 8.1, 9.9, 11.7, 13.7, 15.6, and 17.9 feet respectively for the first ten years. During the period of from 16 to 20 years, height growth decreased and ash ex- pressed its "crowd-enduring" characta-istic. This characteristic is ev- idenced by the occurrence of acutely angled branches and natural pruning of Iowa branches. Stu-rett (11) describes white ash as being able to reproduce -3- In t n under a comparatively dense canopy and seedlings as being able to sur- vive for from five to twenty years in a stunted condition. He states that ash under unfavorable light conditions responds quickly to in- creased light. He adds, that under a canopy in Ohio seedling height was: .5, 1.2, 2.0, 3.0, and 4.0 feet respectively, for five years. He reports that in a clear-cut area in New York and Iassachusetts seedling height was: .5, 1.6, 3.0, 4.6, and 7.0 feet respectively for five years. Sterrett (11) states that white ash seedlings in early life grow faster on a sandy loam soil than on a clay soil, but this advantage is not main- tained. Ash is apparently more tolerant on clay soils. As a recommended cutting practice for ash, Cape (4) suggests a completely closed canOpy until harvest in order to discourage seedlings and suckers of less desirable tolerant species. At harvest he suggests clear-cutting narrow strips, or cpmings of approximately 100 feet in diametc, which would give satisfactory regeneration in from 10 to 20 years. He points out that cleanings may be necessary 5 years after the openings are made. Harley (6) preposes that under certain circumstances white ash seedlings grow best in partial shade and that the shelterwood method of cutting is desirable. Holsoe ('7) reports white ash crown lengths as varying from 1/3 to 3/4 of the stem, based on 100 trees from 3.0 to 18.5 inches diameter breast high. He also found that white ash maintains the same ratio be- tween crown diameter and crown length throughout its develoPment. Con- sequently, he believes ash is easily kept in check by the crowns of ad- jacent tolerants. According to Patton (10), the final objectives for white ash at -4- age 70 years should be a diameter of 12.4 inches breast high, a height of 82 feet with a 50 foot clear bole, and a crown radius of 9.1 feet. Baker (2) in his Revised Tolerance Table suggests that white ash be con- sidered as a tree having intermediate tolerance. Luts and Chandler (9) believe it is possible and practical to adapt forest tree species that will maintain or improve soil fertility. One such soil-improving species is white ash with its high nutrient con- tent in its leaf litter. The major natural agents destructive to white ash are: 1. White rot (£933; fraxinophilus Say.) 2. Ash leaf rust (Puccinia peridermiospe_ra ((Ellis 8: Tr.) Arth.) 3. Oyster shell scale (Lgpidosaphes _u_1_ni;_ L.) 4. Ash borer (Podosesia fraxini Lug.) 5. Lilac borer (Podosesia M29. Harris) 6. Ash bark beetle (Lgperisinus aculeatus Say.) 7. Browsing animals 8. Fire PROCEDURE The basis of this study was 26 areas of natural white ash repro- duction in the beech—sugar maple woodlots of Ingham county.j'/ Small areas varying from 250 square feet to 1,700 square feet in size, with an average of 800 square feet, and containing from 10 to 200 white ash seedlings were selected for obsa‘vations, providing they met the follow- ing requirements: 1. A definite, definable canOpy ova- or or adjacent to the plot. 2. Not too much competition from ground cover. 3. Similarity as to soil type (Hillsdale sandy loam, heavy phase, or Conover loam.). When plots were considered as acceptable in regard to the three require— ments, a series of ten observations was made on each plot. FIELD PROCEDURE The ten observations made on each plot were: 1. 93923: openig—The presence or absence of a canOpy Opening over the plot was noted. If an Opening existed, its area and general shape and the direction of the long axis were recorded. Definite evidence of past history such as a recently closed canOpy was noted. No plots were studied if there was evidence of recent severe disturbance in the ova-head or adjacent canOpies due to logging or windthrow. Can- opy conditions to the east, south, and west of the plot were also studied. Any significant canopy openings in those three directions 5/ There were three plots in Livingston county, in an Oak—Hickory TYPO- -6- as well as the time of day thq influenced the plot, were observed and recorded. 2. m hgight—The canopy was classified into three canopy height classes which were: (a) Low - Saplings less than 15 feet in height; or enough sap— lings under a higher canopy to influence strongly conditions and give the effect of a low canopy. (b) Radium - Young nature timbu', or mature timba' with enough saplings present to average medium height. Genaal height being from 15 to 80 feet. (c) High - Mature timber with minor influence of any other can- epy height class. General height being ova- 80 feet. Any subdominant height class that occurred with the predominant height class, as well as its distribution and direction from the plot were noted. 3. C_§_n_o_gz density—The canOpy was studied with respect to its effect on the plot. The three canopy densities that were used were: (a) Thick—The dense, low type of canOpy gmerally associated with a closed sapling stand. No Openings are present in the can- opy. There may be some overtopping trees in the overstory. Gon- sidering full sunlight as 10 ,000 foot candles, approximately one per cent of full sunlight is present. (b) Medium—The broad range into which most canOpies would be classed. A medium to high continuous canOpy height generally be- ing present, with a few scattered Openings occurring. Consider- ing full sunlight as 10,000 feet candles, approximately one to three per cult of full. sunlight is present. -7- (c) Thin—The sparse but still continuous canopy often exhibited by an oak—hickory stand. Tha'e are new small patches in the canopy, whu-e the crowns do not close. Considering full sunlight as 10,000 foot-candles, approximately three pa' cult or more of full sunlight is present. 4. ‘A__r_g§. g; ELSE—Th" approximate square foot area of the plot was determined by pacing the length and width and multiplying than togeth- a'. The plot was considered the area on the ground between the trunks of the stems of the overstory. Arw distinct shape of the plot as well as the direction of the long axis was also recorded. 5. Ieston Foot-Candle Mate}; readings—Foot-candle meta readings were taken at average reproduction height with the aid of a Weston Phoronic Foot-Candle Meter, Model 614. The readings were taken only betwem the hours of 11:30 A.hl. and 12:30 PJl. which is the period of maximum solar light. A series of from one to five readings was take: on each plot and averaged. Readings were not taken in direct sunlight when an Opening existed, nor in small patches of light that sometime mist under a closed canOpy. The cell in the meter was held parallel to the ground at waist height. An approximation of light conditions was sought. Readings was taken with a range of values and an average taken. The meter was held away from the observer so as to introduce no shadows. Only cloudless, clear days or sparsely intamittent cloudy days wre accepted for readings. No readings were taken when clouds interferred with the sunlight. The following readings were recorded: (1) the reading number, (2) the reading value in foot-can- dles, (3) the date, (4) the time the reading was made, (5) weather conditions prevailing. 6. flail; ;t_y;p_e _a£_d organic £333.31! conditions—Soil types were corre- lated with a United States Bureau of Plant Industry, Soil Survey Map and field checked by the use of a soil auger. The litta' layer (A00 and A0) thickness was also observed and recorded in inches. 7. Topography and; Qosure—The tepography of the plot was noted, and its relation to the general topography was recorded. The corpo- sure of the plot as data-mined by the slepe of the plot surface was also considered as a factor in description. 8. Distribution of; as}; rgproduction _a_n._d_ _t_9_t_a_l_. puma—The distribu- tion of the ash reproduction on the plot was considered. The term “even distribution” was applied to a plot when approximate equality of distribution of ash reproduction occurred. When unequal distri- bution occurred, the condition was described; however, if possible, plots having uneven distribution were avoided. A close approxima- tion of the total number of ash stems on the plot was made. 9. M cometition—The tree species other than ash present on the plot, as well as grasses and herbs, and their condition of vigor and abundance was noted. Relative importance of the effect of the ground competition on the ash reproduction was ocularly estimated and recorded.- 10. Measurement pi ash rgpgoduction—Beight measurements were taken on all ash reproduction that was independent of shading influences by ground competition. By thus restricting the stems studied, the shading effect of the overstory canOpy was isolated. Starting from the leader, the growth for each year was measured to the nearest one tenth of a foot from current growth, back until the groundline was reached. The height growth made each year was determined by measuring -9- the distance between terminal bud scars. Aw stems that were deter- mined to be seedling sprouts were not measured because of the advanced root systens of such stems. OFFICE PROCEDURE A summary sheet of all the plots was made wherein was listed the following items for each plot: 1. Plot number 2. Estimated square foot area of canOpy Opening, if am 3. CanOpy height 4. CanOpy density 5. Average of foot-candle meter readings. It was not possible actually to make foot-candle readings on all the plots on the same day. It was possible, however, to adjust all plot average readings to a base day because adjustment factors could be com-- puted from several plots where daily readings were repeated. The plots located under canOpy Openings were separated from the plots under closed canOpies. The plots under canOpy Openings were fur- ther divided into small Openings of less than 700 square feet and large Openings Of more than 700 square feet. The division resulted in three plots in the small opening class and three plots in the large Opening class. The closed canOpy plots were divided on the basis of adjusted foot-candle meter readings and canOpy descriptions. High canOpy height with thin density and high canOpy height with medium density were con- sidered as one group with available sunlight being three or more per cent of full sunlight. This group consisted of eight plots and was re- ferred to as a light canOpy. Medium canOpy height with medium density, low canOpy height with medium density, and low canopy with thick density -10- wae considered as another group. This group consisted of twelve plots that had from one to three pa cent of full sunlight and is henceforth referred to as a heavy canOpy. All white ash reproduction was divided on the basis of age. The age classes used were from one to nine years, from ten to fifteen years, and over sixteen years. The reproduction in any of the four canOpy con- dition classes would thaefore be subdivided on the basis of age into one, two, or three groups. Theoretically thae would be a total of twelve canOpy—age class divisions, but the data supported only nine such divisions, as shown in Table 1 on page 12. These canOpy—age class di- visions permitted a comparison of the height growth of different age classes within each canOpy class and a comparison of the height growth unda each canopy class for each age class. These comparisons are made in Tables 2 to 5 on pages 22 to 24 and Figures 1 to 6 on pages 25 to 30. The average annual height growths shown in Tables 2 to 5 on pages 22 to 21. were derived by dividing the total height growth made by an age class in a particular year by the number of stems in the age class that was growing that year. The cumulative height growths shown in Tables 2 to 5 on pages 22 to 24 were determined by adding each successive annual height growth, thereby giving the avaage total height per stem within an age class, for a specific year. Table l.-—Smary of division of plots, by canOpy conditions and of division of white ash reproduction by age classes. Age Class Division of Reproduction, in Tears Canopy Condition Rumba of of Plots Plots 1 to 9 10 to 15 16 plus Heavy Canopy 12 Yes Yes Tea Light Canopy 8 Tee Yes Yes Small Opening 3 Yes NO NO Large Opening 3 Yes Yes No -12- DISCUSSION All observations, of the original 10 observations made on each plot, that were not used as a basis of comparison in this study were either held constant and hence didn't affect the problan or tha exhib- ited no correlation. Of the observations thus disregarded were: (1) soil types (2) litter layer thickness (3) typography and exposure (4) distribution of ash reproduction on the plot (5) total number of ash stains on the plot (6) approximate shape of the plots (7) ground vegeta- tive competition. Parallelism of shape exists between curves in some of the age classes in Figures l and 2 on pages 25 and 26. Parallelism is especial- ly consistent in Figure 2 during the paiod of from 191.1. to 1948. This parallelism was investigated for possible correlation with pa cent of possible sunshine or precipitation as shown in Figures 11 and 12 on pages 35 and 36. No definite correlation can be made between any one climatic factor and the average annual height growth. Avaage annual height growth is the result of a combination of climatic factors influencing the site rather than am one climatic factor causing the influence. EFFECTS OF CANOPY CONDITIONS AND AGE CLASS OF REPRODUCTION ON VIGOR Effect of Age of Repgodggtion on Vigor Average Annual Height Growth of White Ash Reproduction Under a Heavy Canopy (Figure 1.) All three age classes are represented in this canOpy class. The curves representing the three age classes in this figure all show a rapid decline in annual height growth during the first I. to 6 years after establishment. This initial decline is followed by a longer pe- riod of gradual decline occurring ova a period of 15 years or more. This pattern, or portion of it, is found exhibited in all the age class- es in this canopy condition class. There is some parallelism of curves expressed during the period of from 191.3 to 1949. The parallelism is not too strongly expressed be- cause Of the low vigor Of the two olda age classes, and especially the 16-plus-year age class. This low vigor tends to mask the effect of cli- matic influences. An annual height growth of four tenths (0.1.) of a foot was arbi- trarily considered as acceptable growth for white ash reproduction. A few years after establishment, all the age classes in the heavy canOpy class had fallen below that value and never rose up to it again. Avaage Annual Height Growth of White Ash Reproduction Under a Light Canopy (Figure 2.) This canopy class has all three age classes represented by field data. The curves for the 1 to 9 and the 10 to 15 year age classes are similar during the last six years. An upward trend in vigor has occurred the last few years in those two age classes. The avaage annual height growth for the two younga age classes has generally been above the ar- bitrarily acceptable value of four tenths (0.4) of a foot. The curve for the lO-plus-year age class does not follow the trend that is found in the curves of the two younga age classes. The l6-plus- year drOpped in vigor eight years after establishment and in general -14- ra’nained low in vogor thereafter. The 10 to 15 year age class should exhibit this same trend if it is significant. Howeva, the 10 to 15 year age class did not behave in such a manna. The 10 to 15 year age class curve was based on ova six times as new observations as the 16- plus-year age class curve was. Consequently, the lé-plus-year age class unda a thin canopy was considaed as not as significant as the 10 to 15 year age class and was disregarded. There is a definite parallelism among all age class curves es— pecially from 191.1. to 191.8. This parallelism is discussed under the genaal discussion on page 13. Avaage Annual Height Growth Of White Ash Reproduction Under Small Canary Openings (NO Figm-e) Only the 1 to 9 year age class is represented in this canOpy class. The figure representing the reproduction under a small canOpy Opening was not constructed. Since only the 1 to 9 year age class was represented thae was no basis of comparison within that canOpy class. The curve for this age class can be found in Figure 5 on page 29. The l to 9 year age class curve does show a fairly constant range of annual vigor and is above the arbitrary four tenths (0.4.) of a foot annual height growth. Average Annual Height Growth of White Ash Reproduction Under Large Canopy Openings (Figure 3) The lé-plus-year age class in this canOpy class was not represent- ed by field data. In genaal the curves show a maintenance, if not an increase, of annual height growth. The avaage annual height growth was -15.. genaally greater than the arbitrary four tenths (0.1.) of a foot. Effect of Canopy Clggs on Vigor of Rmoduction Avaage Annual Height Growth of the l to 9 Year Age Class of White Ash Reproduction Unda Various CanOpy Conditions (Figure 4) All canopy condition classes otha than the heavy canOpy exhibit close proximity in vigor. The heavy canopy has much lower vigor than the otha classes as its curve shows a downward trend. The other cano— py condition classes ahibit good vigor as expressed by their annual height growth. The heavy canopy curve shows less than four tenths (0.4) of a foot height growth while the otha curves have growth that is great- fl'o Avaage Annual Height Growth of the 10 to 15 Year Age Class of White Ash Reproduction Unda Various Campy Conditions (Figure 5) The curves representing ash reproduction unda a light canopy or large Openings are close togetha and are above the arbitrarily accept- able four tenths (0.4.) of a foot annual height growth. The curve repre- senting ash reproduction unda a heavy canopy has a definite downward trend which places it far below the acceptable four tenths (0.1.) of a foot annual height growth. NO field data for reproduction under small canopy Openings was availabl e. Avaage Annual Height Growth of the 16—plus-year Age Class of Ihite Ash Reproduction Under Various Canary Conditions (Figure 6) The curve for the light canOpy condition is to be disregarded for -16- the reasons explained in the discussion of Figure 2 on page 11.. The curve representing heavy canOpy conditions has a definite cumulative de- crease in vigor as expressed by the smell annual height growth. Field data for reproduction under canopy Openings in this age class was not available. Cumulative Height Growth of the l to 9 Iear Age Class of White Ash Reproduction Under Various CanOpy Conditions (Figure '7) The cumulative height curves show how closely the canOpy condi- tion classes, otha than the heavy canOpy, resemble each otha in their effect on height growth. The cumulative height growth for the canopy condition classes, otha than the heavy canOpy, approach the position of a 45 degree line. Cumulative Height Growth of the 10 to 15 Year Age Class of White Ash Reproduction Under Various Campy Conditions (Figure 8) The curves for the light mom and large Openings are approxi- mater the same shape and occupy the same position. The cumulative height growth for these canopy condition classes approximates the po- sition of a [.5 degree line. Field data for reproduction unda small Openings in this age class was unavailable. The cumulative height growth of the heavy canOpy class is in- creasing at a decreasing rate. The curve has already begun to level off. Figure 11 on page 35 shows the comparison between these curves by using a canon origin. Hence, the difference between them is more appar ent . -17- Cumulative Height Growth Of the 16-plus-year Age Class of White Ash Reproduction Under Various CanOpy Conditions (Figure 9) The curve representing the light canOpy is to be disregarded for the reasons explained in the discussion of Figure 2 on page 26. A leveling off of the heavy canopy curve as described in the discussion of Figure 9 on page 33 is also found in Figure 10 on page 34.. This constant reduction in annual height growth can only result in death of the trees. NO field data was available for ash reproduction in this age class under canOpy openings. GENERAL DISCUSSION OF A COMPARISON OF CANOPY CONDITIONS The effect of canOpy conditions on the vigor of white ash repro- duction breaks down into one of two conditions. A heavy canopy results in one condition, while a light canopy or canOpy Openings result in an- other condition. These two conditions are subsequently discussed. Heazz Canopy Conditiog Unda a heavy canopy white ash reproduction of all age classes exhibited a rapid decline Of vigor during the first 4 to 6 years after germination. This rapid decline is followed by a much longa period of 15 years or more of gradual decline in vigor. These vigor reductions follow essentially the same pattern for each age class and are shown in Table 2 on page 22, and Figure l, on page 25. No stems was found that had increased their rate of annual height growth afta having been growing at a rate of less than five hundreths (.05) of a foot per year for three or more successive years. The curve -13... for the l6-plusfiyear age class in.Figure l on page 25 has reached an 'average of five hundredths (.05) of a foot height growth per stem per year. It seems evident that the majority of the trees in this age class are of such low vigor that they cannot recover and will probably die within the next few years. The maximum age of am tree within this can- opy condition class was 23 years. Reproduction under heavy canOpies had poorer current vigor in all its age classes than reproduction under other canopy conditions; refer to Table 2 on page 22, and Figures 4, 5, and 6 on.pages 28, 29, and 30 respectively. An arbitrary value of four tenth (0.4) of a foot height growth per stem per year was considered as acceptable growth. The reproduction under a dense canopy falls below this value 4 to 6 years after germination. NO recovery is ever achieved and a gradual de— cline of vigor occurs. The principle cause of low vigor of white ash reproduction under these heavy canOpies has undoubtedly been low light intensities, though it is possible that relatively severe root competi- tion may also have been of major importance as a factor. This conclus‘ sion was reached because an Objective of the study was to select plots where, within.practicability, canopy condition and the resultant solar light intensity were the only variables. Cumulative height growth for reproduction in all age classes is inferior to that of the reproduction under other canOpy conditions as shown by Table 2 on page 22, and Figures 7, 8, 9, and 10 on pages 31, 32, 33, and 34 reapectively. Under heavy canOpies total height has be- gun to level off, while under the light canopies and under the canopy openings the total height is still steadily increasing. This inferior cumulative height growth of reproduction under a heavy canOpy was due -19.. to its low vigor as eocpressed by its small annual height growth. Data taken in the field showed five stems that were dead under a heavy canopy. The age of these stems was from 10 to 17 years. These were the only stems that were found that were dead. They give an indi- cation of the range of age during which reproduction under a heavy can- Opy will die. Because of the poor vigor of ash reproduction under a heavy can- Opy (three per cent or less of full sunlight) it is suggested that white ash regeneration should be sought under a heavy canopy only in special cases. That is, only when it is proposed that some type of re- lease cutting will be made. These release cuttings should be made be- fore the majority of the reproduction is 10 years old because loss in vigor due to delay may result in death. Light Canopy Conditions and Canopy Qpenings The light canOpy, smell canopy Openings, and large canopy open- ings result in essentially the same vigor conditions for white ash re- production. This statement is substantiated by Figures 7, 8, and 10 on pages 31, 32, and 34 respectively, showing annual cumulative heights - for the reproduction under a light canopy and under canOpy Openings. Vigor within the I to 9 and within the 10 to 15 year age classes are very similar as illustrated by Figures 4 and 5 on pages 28 and 29 respectively. The vigor of the l6—plus-year age class under a light canOpy as shown in Figure 2 on page 22 was not considered typical and was disregarded. The reasons for disregarding that age class data are explained in the discussion of Figure 2 which is on page 22. The various age classes of reproduction under light canOpy -20.. conditions or under canopy Openings showed a relatively small range of variation of vigor. That is, all age classes were approximately the same in vigor. This is in contrast to the vigor under heavy canOpy con- ditions where a patta'n of vigor decrease is evidenced. White ash reproduction under a light canOpy (three or more per cent of full sunlight) or under canopy Openings had supa'ior growth, within the same age class, to reproduction under a heavy canOpy. The good vigor Of ash reproduction under a light canopy or under Openings was sustained as shown by Tables 3 and 5 on pages 23 and 24, and Fig- ure 8 on page 32. Even after 15 years of growth there appeared to be no need of release cuttings under those canOpy conditions. The repro- duction maintained a steadily rising cumulative growth. It is prob- able that release cuttings will not be needed as seriously as they are needed under heavy canopy conditions. Consequently it is suggested that white ash reproduction should be sought under light canOpies or under canopy Openings. 33 semH SmH mme _qo mm mm. 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H .J.o ... lufi...wim H. a H. 3 dflllH...oq|_l.IAna$n 18 Haw dew Hé Indian.“ awards 333 stage 333 so 5.55 Ewan no 338» OPH Pad . oz Hug-”nu 0PHPdH . oz H.355 obH HwH . 02 Hand 0.255 0 menu be tease oweambd Isaac eweue>4 endow endow |nmlHe4¢mH usHauoH maeHo owe mH 3 0H mass .3 z m as H «$8 .3 steam HUGH quH 43.0.3 NH no women; 33.3800 Rondo been .893 noaaosvoumeu and 2:33 we £9.85 EMHOA 0583.50 H.398 eweuge use Anion» “338A Humane 09526 HO ngl.w 03¢“. -22.. .888..qu 2. 388 e8 8338 0320 means 80.88 8s. 38 an; \m -23- 84H Jm H34 «.3 l3. swam Ala. mm 86 memH 8.8 s 8H 8.1» 3 86 8.«.H mm one 33 8.8 e m«.H man 3 3..» 3.8 R mmé $3 8.8 s 8.« m«.Hm 3 8.« mmém on ««.m AHRH 8.3 s eH.H 8.3 3 $8 8.8 on mm.m SmH 3.9 s m«.m 8.3 .3 8..“ sm.«« em wmé 32 8.3 s 8.« «0.8 3 8.« mméH m« 8.« 93 mmfim N. Q.H «8mm 3 «Tm 3.9 o« and «..HmH 8.8 s m«.H om.m« 3 om.m 8s m 8s QmH 3.8 a .HH.« 3.8 3 m3 0qu 8.«m a 8.« ««.«« mm 21‘ mmmH 3.0m K. m«.« «H.mH «m mHé mmmH H«.m« a oo.m mm.mH m« 3.4 5.an H«.m« 5 Rs. $.m «H «mé @an 3.3 N. 8.« 3.3 .a. £3 «an mm.mH s 33 «mmH om.HH « emé mmmH 8;. H 8.« «an oo.m H oo.m HmmH a t IH.Jo «881418. 1.0 18 H. 8 inaoiwlw .4.I£.H:.3 . [Hula inane... .13 H.o 3 ._ _. ..Ileua £33 .8 stone £33 85.6 .533 no Assam 3.. 25 we." . oz gene 05 pea . O z dawned opened . oz Humane £5.95 0:56 manage lease emanate IHEHG @3995 «Be» endow mHeOH umlreheoH s.HaueH 238 .3 mH 3 0H $30 .8 m on H mmuHo .3 435.3 m no peace 833:3 3083 new: house soapepeouAOH and 09.3: Ho .3395 .330: chassis—He Hashes 09323 Hone naboum Emacs H358 0998b.» no gall. m 0.33.. Table 4.-—Summary of average annual height growth and average annual cumulative height growth of white ash reproduction.under small canon openings (based on 3 plots). Age Class 1 to 9 Year; Year Average Cumu- growth annual Number lative was growth height mags; (0.1 ft) st :1ng (O. 1 ft.) ‘ 191.1 6.20 5 6.20 1942 6.50 18 12.70 191.3 6.35 26 19.05 194/. 4.39 33 23.44 1945 4.17 36 27.61 1946 4.51 37 32.12 1947 4.37 1.3 36- 1.9 1948 4-00 1.0.1.9 13.41 5.9M Table 5.-—-Sumary of average annual height growth and average annual cumulative height growth of white ash reproduction under large canopy openings (based on 3 plots). Age Class 1 to 9 Ag e Class 10 to 15 Yeja_r_§ Years I ear Average Cumu- Average Cumu- gronth annual No . lative annual No . lative was growth of height growth of height made .1 ft. st 0 1 ft. 0.1 ft. st .1 ft. 1936 6.00 1 6.00 1937 1 .00 l 7.00 1938 1 .00 1 8.00 1939 5 .00 2 13 .00 1940 5 .67 3 18 .67 1941 6.67 ' 3 6.67 4.67 3 23 .34 1942 1.. 85 13 11 .52 3 .67 3 27 .01 1943 4.19 21 15.71 5.67 3 32.68 191.4 4.8!. 37 20.55 6.00 3 38.68 191.5 3.80 41 24-35 4.00 3 42.68 1946 3 . 84 49 28.19 6 .33 3 1.9.01 191.7 4.30 56 32.19 6.33 3 55 .34 1948 5.24 63 37.73 3 .00 3 58.34 1242 ya 63 1.1.4.54. 5.99“ 3 63.21L 1950 nu ,0 “w “4 Au av lo 14 n4 nu RV ,0 ,4 14 ,4 14 a; 92 a) a; a; a4 “4 q, o/ o/ o/ 01 oz 0/ o/ o, o, q, q, l l l l l l l l l l l l _ _ _ . . _ _ _ _ _ . _ a. /, ,, \\ / , , ,, ‘ \ fl. x, \\ d. mmmao 0mm nwmhfmdamloall mmmao oww pmmh ma on OHII mmwao mmw nwmh m on all "czmmoq .mnoapfiuaoo hmozwo hwwmn nmcns moapodcoummn and mpagt mo .ampm ham npaoam pQMng stunw mwmnm>¢fl.a mnfimwh Average height growth per year (0.1 of a foot) 1950 -l946 -1944 -1942 -1932 -l930 -1928 -1926 -l940 ~1938 -l936 ~1934 mmmao owm ndthmnamloHII mmwao owe yeah MA 09 OHII mmwao 0mm uwmh m on HI: “uzmmoq .mdoapannoo mmocwo pawwa nevus :Ofiposfionmmu nmw mean: no .Empm ham Apachm unmflon dengue omwuwbqnl.m onsmah Average height growth per year (0.1 of a foot) 1950 HQGH. 8 2 O 8 6 w m u a m w W» m e w w w, my D N N 1 1 1 1 1 1 1 1 _ . . _ _ _ _ . _ _ . _ 1f 4 1 J ,1 , ,/ 1,, I .r 1 , f. unwao owe amok ma op CHI! www.mo own 53» m. ow HI. nunomoq .mwaauomo hmocmo mmpwa .893 qoaposvoummn and win: no :Bpm hum suboum pnmamn and“ omwnm>4llm PBMHM ....m IN Average height. growth per year (0.1 of a foot) —l950 ~1948 -1946 -l944 -l942 -l940 —l938 —l936 -l934 -l932 ~1930 —l928 -l926 Awaaammo ownwav mmwao mmw Adah m op Ari Awnaomo Hawamv mnwao owe .58» m. 0» HI Ahmoawo pnwflav mmwao 0mm yeah a on HT: Ahmonwo hemmnv mmdao 0mm Adah m on HII uvnmwoq IH IN .mmwmwao noapwunoo nuance Ham hangs wmwao emu yeah 0 cg H map aw QOfiponcougou awe mafia: mo .Eopm Mom anion» pnmaon Amanda omwhm>«li.< muswah Average height growth per year (0.1 of a foot) - 28 - ~195O Moo» -1946 -l944 -l942 ~1936 ~1934 -l948 -l940 -l938 ~1932 —l930 -l928 -1926 IH IIIl////////\\\\>/ IN um \ / Ia .\ / / \ ...\ .. \ -m \ \ Io Ib - Awawqomo omnoav mmoao omw pooh ma ow CHI: Ammonmo unmfiav mmwao owe hook ma ow CHI: Ammonwo h>wmnv mmoHo omm nook ma op CHI. Im «ngowoq 1w .mmmmoao noapauaoo haoqoo moan» good: woman owe nook ma on 0H esp aw :owpoawonmou nmo avast mo .aopn pom neeouw pnmfion Hammad omouo>prHE§o mmmpwbHIS 95mg IH Average cumulative height (in feet) -31.. 1950 -1948 -l944 ~1942 4-940 -193 8 -1936 -1934 -1932 -l930 -l928 4-926 -1946 332890 owned mmoHo own .39» mH op CHI Ahmocoo pnMHHv mndHo owe Hook «H on. CHI A3093 broods amoHo emu .30.» mH op CHI 39¢on .nommoHo 333:3 Rondo 83¢ Bug nogonéonmon now no.3: mo :83 non macaw .330: 05.5%“. oonoBHIé 9333 Average cumulative height’ (in feet) -32- -l950 -l948 4946 ~1944 -l942 -1940 -1938 -l936 ~1934 ~1932 Ll930 -l928 Ll926 IH IN um I« In ‘@ lb Ahmozoo panHV mdeo 0mm pooh.lmflHmI©HII Ahmoowo hpomav mmeo omo noohfmsHmICHII Iw “unomoq m .mmmmeo :oHpHCnoo hmozoo can haven aoHpoaConmmu new opflna mo .ampm “on npkoum panon oproHseno omwum>4ll.m onflmwm Average cumulative height (in feet) - 33 - _24 1.5153233 1.3.3 28» -22 —20 ~18 -16 :4 “2 .U 1.1 1.1 4 Aquoomo omnoHV wmeo 0mm nook mH op CHI: Ahmoaoo pnMHHV mmeo owe pooh mH op CHI: Humanoo hpoonv mmeo 0mm nook mH op CHI: “camwoq Amommeo owe HHo pom :HMHuo meow map no women m onzmpmv .mmwmoHo :oHpchoo hmonoo mongp noun: noHpoovoumop and opan mo .aopm mom npaoum pQMHon oprwHuaso omwnmbaII.CH ouwah Average cumulative height (in feet) - 34 _ wemH neaH mama meaH «amp eaeaaaa 1114414 1144414 1144414 114J414 ouoHo emu H8» mH op CH onp mo anyone pemaoa Hugged mo nopppuoa opppaHom . omdpnoouom apnea ngo