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The effect of some environmental factors on the morphological characteristics of western hemlock seedlings… Soos, Joseph 1961

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THE EFFECT OF SOME ENVIRONMENTAL FACTORS ON THE MORPHOLOGICAL CHARACTERISTICS OF WESTERN HEMLOCK SEEDLINGS (Tsuga h e t e r o p h y l l a ( . R a f o ) ISargo) by JOSEPH SOOS Dipl« F o r . Engo U n i v e r s i t y of Sopron Hungary 1953. A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR DEGREE OF MASTER IN FORESTRY i n the F a c u l t y of F o r e s t r y We accept t h i s t h e s i s as conforming t o the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1961 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s m a y b e g r a n t e d b y t h e H e a d o f my D e p a r t m e n t o r b y h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t b e a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f fbres//*/  T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r $ , C a n a d a . ABSTRACT, The objective of the study reported in this thesis i s to assess the influence of light and site quality on the mor-phology of western hemlock Tsuga heterophylla (Raf<>) Sarg, seedlings 0 The importance of western hemlock to the present and future economy of British Columbia i s emphasized0 The s i l -v i c a l literature on the species i s reviewed, The inadequate treatment given western hemlock in the technical literature i s noted and the point i s made that, as the hemlock forests are exploited and new forests regenerated, information on the s i l v i c a l characteristics of the species w i l l be needed, At the present time, knowledge of the s i l v i c s of western hemlock i s very limited. This thesis attempts to add to knowledge in that f i e l d with particular reference to some factors (light microsite and site) which influence the juvenile growth of western hemlock on the University of Br i t i s h Columbia Research Forest, near Haney, B 0C 0 The effect of light intensity was studied through measure ments of natural regeneration growing on 10 plots, under f u l l light and under different degrees of canopy closure, in a 77-year-old stand. Measurements included height, diameter and number of green and dead branches. The influence of different microsites was studied on three-year-old wild seedlings and on 1 -J- 1 planted seedlings, with particular reference to height, stem diameter at ground level, number of branches, length of needles, angle of branches, diameter of branches p weight and depth of r o o t s , and root/shoot r a t i o 0 Four-and f i v e - y e a r - o l d w i l d l i n g s growing on p l o t s with known s i t e i n d i c e s were s t u d i e d with p a r t i c u l a r r e f e r e n c e t o maximum needle l e n g t h and branch angle of l a s t y e a r ' s shoots«, The r e s u l t s i n d i c a t e t h a t diameter and height growth i n c r e a s e d d i r e c t l y with i n c r e a s e d l i g h t and t h a t s e e d l i n g s cannot s u r -v i v e with l e s s than t en per cent of f u l l l i g h t (measured on cloudy daysj« The average minimum l i g h t i n t e n s i t y was found t o be 117 f o o t - c a n d l e s f o r a 12-hour p e r i o d on b r i g h t days. S e e d l i n g s s t u d i e d on f i v e types of m i c r o s i t e s showed s i g n i f i c a n t l y d i f f e r e n t e x t e r n a l c h a r a c t e r i s t i c s i n h e i g h t , diameter, maximum l e n g t h of needles and angle of branches of the l a s t i n t e r n o d e . These c h a r a c t e r i s t i c s were then s t u d i e d on p l a n t e d w i l d l i n g s of l o c a l provenance on p l o t s of known s i t e i n d i c e s . The r e s u l t s show t h a t , a f t e r two y e a r s , the mor p h o l o g i c a l c h a r a c t e r i s t i c s of hemlock p l a n t e d on d i f f e r e n t s i t e s , were m o d i f i e d t o l e v e l s a s s o c i a t e d w i t h s i t e q u a l i t y . . These m o d i f i c a t i o n s i n v o l v e d branch angle, maximum needle l e n g t h , and height growth„ I t was concluded t h a t , w i t h i n a p a r t i c u l a r provenance, the i n f l u e n c e of environment i s of g r e a t e r s i g n i f i c a n c e than h e r e d i t a r y f a c t o r s , i n super-imposing m o d i f i c a t i o n s on the b a s i c form of western hemlock s e e d l i n g s o The p o s s i b i l i t y of u s i n g branch angle and maximum needle l e n g t h t o estimate s i t e q u a l i t y i s noted. X X I C O N T E N T S Page I 0 ABSTRACT IA o ACKNOWLEDGEMENTS I I . INTRODUCTION 1 I I I o DESCRIPTION OF STUDY AREA 8 Ao U n i v e r s i t y of B r i t i s h Columbia Research F o r e s t 8 B 0 C l i m a t e 9 IV. METHODS A 0 The I n f l u e n c e of L i g h t I n t e n s i t y on Hemlock S e e d l i n g s 11 Bo The E f f e c t of M i c r o s i t e on the E x t e r n a l C h a r a c t e r i s t i c s of Three-Year-Old S e e d l i n g s 14 a. M i c r o s i t e 1 14 b. M i c r o s i t e 2 15 c« M i c r o s i t e 3 15 d 0 M i c r o s i t e 4 Io e« M i c r o s i t e 5 Io Co The I n f l u e n c e of S i t e on Hemlock S e e d l i n g s 17 Vo RESULTS Ao The I n f l u e n c e of L i g h t I n t e n s i t y on Hemlock S e e d l i n g s 20 a. The amount of l i g h t 20 bo The i n f l u e n c e of l i g h t i n t e n s i t y on t o t a l h eight of s e e d l i n g s 21 c. The i n f l u e n c e of l i g h t i n t e n s i t y on the age t o reach b r e a s t height 21 d 0 The e f f e c t of l i g h t i n t e n s i t y on diameter growth 22 e 0 The i n f l u e n c e of l i g h t i n t e n s i t y on d e n s i t y of f o l i a g e 23 CONTENTS (Cont*d) iv Page f<» Light intensity and form quotient 23 g» Natural pruning and light intensity 23 B„ The Effect of Microsite on the External Characteristics of Three-Year-Old Seedlings 24 a e Total height 24 b« Base diameter 24 c e Weight of roots 25 d 0 Depth of roots 25 e 0 Weight of needles 26 f. Root/shoot ratio 2b g 9 Total number of branches 27 h 0 The average number of branches by 27 internodes i» Average branch angle of internodes 27 3o Average length of largest needles by internodes 28 k a The average length of branches by internodes 29 1 0 The average base diameter of branches by internodes 29 ma Bark thickness 30 C 0 The Influence of Site on Hemlock Seedlings 30 a, Height growth 30 b» Branch angle 30 C o Length of largest needles 31 VI, DISCUSSION A 0 The Influence of Light Intensity on Hemlock Seedlings 33 B o The Effect of Microsite on the External Characteristics of Three-Year-Old Hemlock Seedlings 35 Co The Influence of Site on Hemlock Seedlings V o CONTENTS (Cont*d) Page V I I . CONCLUSIONS 42 V I I I , TABLES 44 IX, GRAPHS 64 X 0 BIBLIOGRAPHY 85 XI, APPENDIX v i T A B L E S Number Page 1 0 Occurrence of ground vegetation on the three micros i tes f o r study of the e f fect of micro-s i t e s on the external c h a r a c t e r i s t i c s of hemlock seed l ings 0 44 2 e Phys i ca l c h a r a c t e r i s t i c s of the f i v e p l o t s f o r study of the e f fect of s i t e on hemlock seedlingso 45 3« Depths of s o i l horizons and the t ree -roo t penetrat ion of f i v e p lo t s f o r study of the e f fec ts of s i t e on hemlock seedl ings . 46 4. Occurrence of ground vegetation on the f i v e p lo t s f or study of the e f fec t of s i t e on hemlock seed l ings 0 47 5o The inf luence of l i g h t i n t e n s i t y on hemlock seedlingso Light i n t e n s i t y data on a br ight day f o r eleven and s i x - y e a r - o l d seedlings,, 48 b 0 The inf luence of l i g h t i n t e n s i t y on hemlock seedlingso L ight i n t e n s i t y data on a cloudy day (complete overcast) f o r eleven and s i x -year- old s e e d l i n g s „ 49 7© The inf luence of l i g h t i n t e n s i t y on hemlock s e e d l i n g s « Some external c h a r a c t e r i s t i c s of e leven-year-o ld hemlock seedl ings on two p l o t s of various degrees of shade 0 50 bo The inf luence of l i g h t i n t e n s i t y on hemlock seedl ingsa Some external c h a r a c t e r i s t i c s of e leven-year-o ld hemlock seedlings on three p lo t s of various degrees of shade, 51 9o The inf luence of l i g h t i n t e n s i t y on hemlock seedlingso Some external c h a r a c t e r i s t i c s of s i x - y e a r - o l d hemlock seedlings on two p l o t s of various degrees of shade 0 52 10e The inf luence of l i g h t i n t e n s i t y on hemlock seedlingso Some external c h a r a c t e r i s t i c s of s i x - y e a r - o l d hemlock seedlings on three p l o t s of various degrees of shade 0 53 11 0 Some external c h a r a c t e r i s t i c s of three-year-old hemlock seedlings on M i c r o s i t e 1 3 54 12o Some external c h a r a c t e r i s t i c s of three-year-old hemlock seedlings on M i c r o s i t e 2. 55 v i i TABLES (Canted) Number 13 a Some external c h a r a c t e r i s t i c s or' three-year-old hemlock seedlings on Microsite 3o 14a Some external c h a r a c t e r i s t i c s of three-year-old hemlock seedlings on Microsite 4o 15o Some external c h a r a c t e r i s t i c s of three-year-old hemlock seedlings on Microsite 5, l b . C h a r a c t e r i s t i c s of branches of three-year-old hemlock seedlings i n r e l a t i o n to i n t e r -node and microsite {.Averages of 10 seedlings per microsite), 17« Student*s t - t e s t values f o r the comparison of the mean t o t a l height of hemlock seedlings on f i v e microsites, 18o Student*s t - t e s t values f o r the comparison of the mean base diameter of hemlock seedlings on f i v e microsites, 19o Student*s t - t e s t values f o r the comparison of mean branch angle of t h i r d internode of hemlock seedlings on f i v e microsites. 20o Student*s t - t e s t values f o r the comparison of mean length of largest needles of t h i r d inter-node of hemlock seedlings on f i v e microsites, 21, Student's t - t e s t values f o r the comparison of mean oven-dry weight of needles ( i n gramsj of hemlock seedlings on f i v e microsites, 22© The influence of s i t e on hemlock seedlings. The mean length of largest needles, branch angle of l a s t yearns internode, and height growth of hemlock seedlings e 23o The influence of s i t e on hemlock seedlings. Student's t - t e s t values f o r comparison of mean branch angle of l a s t y ear 8s internode of hemlock seedlings on f i v e p l o t s , 24o The influence of s i t e on hemlock seedlings, Student*s t ~ t e s t values f o r the comparison of mean length of largest needles of l a s t yearns internode of hemlock seedlings on f i v e p l o t S o Page 56 57 58 59 60 60 61 61 62 63 64 65 v i i i TABLES lCont*d) Number Page 25. The influence of s i t e on hemlock seedlings 0 F i d u c i a l l i m i t s at 0 001 l e v e l calculated f o r the mean branch angles (.in degrees) of hemlock seedlings on f i v e plots <, 66 26o The influence of s i t e on hemlock seedlings 0 F i d u c i a l l i m i t s at 0 o01 l e v e l calculated f o r the mean of largest needles I i n m i l l i -meters) of hemlock seedlings on f i v e p l o t s 0 6b 27o Estimation of s i t e index of microsites by using needle length and branch angle of hemlock seedlings 0 67 i x 0 ILLUSTRATIONS Figure Page l a Location or' plots established for various studies« Appen-dix 2o Cumulative light intensity of various degrees of shade for 12-hour period of bright day. 68 3e Cumulative light intensity of various degrees of shade for 12-hour period of bright day© °9 4o Cumulative light intensity of various degrees of shade for 12-hour period of cloudy day 0 70 5o Cumulative light intensity of various degrees of shade for 12-hour period of cloudy day 0 71 bo Average cumulative length of internodes of 11-year-old seedlings on plots of various degrees of shade9 72 7o Average cumulative length of internodes of six-year- old seedlings on plots of various degrees, of shadeo 73 b 0 Average cumulative diameter of internodes of eleven-year-old seedlings on plots of various degrees of shade0 74 9o Average cumulative diameter of internodes of six-year- old seedlings on plots of various degrees of shadeo 75 10o Average cumulative number of green branches of eleven-year-old seedlings on plots of various degrees of shade, 76 l i e Average cumulative number of green branches of six-year-old seedlings on plots of various degrees of shade a 77 12© Average total height of three-year-old seedlings on various micrositeso 78 13a Average base diameter of three-year-old seedlings on various micrositeso 78 14• Average oven-dry weight of roots of three-year-old seedlings on various micrositeso 79 15 a Average depth of roots of three-year-old seedlings on various micrositeso 79 16o Average oven-dry weight of needles of three-year-old seedlings on various microsites, 80 ILLUSTRATIONS (Ccnt^d) Figure Page 17o Average number of green branches of three-year-old seedlings on various m i c r o s i t e s 0 80 18 s The average branch angle of three internodes on various micrositeso 81 19o Average length of largest needles of three i n t e r -nodes on various microsites, °"1 20o Average length of branches of three internodes on various micrositeso ^2 21B The average base diameter of branches of three i n t e r -nodes on various microsites, 82 22o Regression l i n e based on branch angle and s i t e f o r study of the influence of s i t e on hemlock seedlings<y3 23o Regression l i n e based on length of needles and s i t e f o r study of the influence of s i t e on hemlock seedlings, 84 XX o ACKNOWLEDGE*® NTS The author wishes to express h i s thanks to; Dr„ PoGo Haddock,associate professor swho directed and advised the investigation,, Mr, Jo Walters, research f o r e s t e r , who advised and encouraged the author throughout the study, Dr, JoG.H. Smith, associate professor, f o r his suggestions and c r i t i c i s m s Mr D L 0 Orloczy f o r his assistance i n i d e n t i f y i n g the species of minor vegetation. I N T R O D U C T I O N Almost 72 per cent of the la n d area of B r i t i s h Columbia i s f o r e s t e d . In terms of ar e a , western hemlock, Tsuga  h e t e r o p h y l l a (Raf) Sarg, i s the f o u r t h most important s p e c i e s , b e i n g a component of stands c o v e r i n g 8,684,876 a c r e s . Of t h i s a r e a , 1,1 m i l l i o n , 7o2 m i l l i o n and 0,3 m i l l i o n a c r e s , support immature, mature and overmature stands, r e s p e c t i v e l y . The l a r g e area s u p p o r t i n g mature stands, i n d i c a t e s the im-portance of hemlock i n the contemporary and f u t u r e economy of the P r o v i n c e , The volume of western hemlock 155«6 b i l l i o n c u b i c f e e t ) i n B r i t i s h Columbia, i s second o n l y t o th a t of the spruces (92,8 b i l l i o n c u b i c f e e t ) , and i s almost double t h a t of Douglas f i r (30,6 b i l l i o n c u b i c f e e t ) 0 On the coast the volume of western hemlock i s t r e b l e t h a t of Douglas f i r (Continuous F o r e s t Inventory of B r i t i s h Colum-b i a , 1957)o These data serve t o emphasize the importance of western hemlock. Hemlock i s the p r i n c i p a l s p e c i e s used i n the pulp i n d u s t r y of the p r o v i n c e . I t has a l i g h t e r c o l o u r and l e s s pronounced g r a i n than Douglas f i r . The cause of unpopul-a r i t y of hemlock i s that i t i s l e s s d e s i r a b l e f o r c e r t a i n uses than Douglas f i r or more d i f f i c u l t t o p r o c e s s , The moisture content of hemlock i s h i g h e r than Douglas f i r and i t t akes l o n g e r t o d r y j sanding i s l e s s s a t i s f a c t o r y and l e s s f a c e veneer i s produced. The advantages of hemlock - 2 -i v t o the lumber and plywood i n d u s t r i e s are t h a t the product i s l i g h t e r than f i r , thus i t c o s t s l e s s t o s h i p 0 The g r a i n i s more a t t r a c t i v e and i t s p a i n t i n g c h a r a c t e r i s t i c s are b e t t e r than f i r (Wellwood 1957)° Western hemlock grows a l o n g the P a c i f i c Coast, from A l a s k a t o Northern C a l i f o r n i a . I t a l s o ranges i n l a n d i n a narrow, s c a t t e r e d p a t t e r n a l o n g the U n i t e d States-Canadian bo r d e r , and then spreads out through Northeastern Washing-t o n , Northern Idaho, Northwestern Montana and throughout Southeastern B r i t i s h Columbia. Average annual p r e c i p i t a t i o n i n the c o a s t a l hemlock r e g i o n v a r i e s from 38 i n c h e s t o over 100 i n c h e s (.Berntsen 195«Jo A c c o r d i n g t o H a l l i d a y and Brown (1943.J > the best stands of western hemlock are on the Queen C h a r l o t t e I s l a n d s and the nor-t h e r n p a r t of Vancouver Island„ The d i s t r i b u t i o n eastward i s i n t e r r u p t e d by the I n t e r i o r Dry B e l t , but i t reappears on the r a i n y westward s l o p e s of the Columbia, S e l k i r k , P u r c e l l and Rocky Mountains„ K r a j i n a (1959) d i s t i n g u i s h e d two western hemlock zones i n B r i t i s h Columbia: a) C o a s t a l Western Hemlock Zone and b) I n t e r i o r Western Hemlock Zone, Rowe (1959) c a l l e d the area of the I n t e r i o r Wet B e l t , the "Columbia F o r e s t Region". F l o w e r i n g and f r u i t i n g h a b i t s of western hemlock were des-c r i b e d by the F o r e s t S e r v i c e U.S. Department of A g r i c u l t u r e - 3 -(1948), and by Berntsen (1958), The male and female f l o w e r s are monoecious and are on d i f f e r e n t branches of the same t r e e . The p o l l e n shedding begins about one month l a t e r i n A l a s k a than i n Washington ( D a l l i m o r e and Jackson 1948) e The average weight of one thousand seeds shows a t e n -dency t o decrease from south t o n o r t h , Wiksten (1952) r e -p o r t e d 1,23 grams per thousand seeds i n the Queen C h a r l o t t e I s l a n d s , w h i l e a c c o r d i n g t o Garman (1951) the average weight of one thousand seeds was 1,7 grams on Vancouver I s l a n d , Western hemlock i s very p r o l i f i c , p r o d u c i n g a heavy seed crop at an average i n t e r v a l of 2,1 years i n the western white pine type (Haig 1941)« Godman (1953) r e p o r t e d a bum-per crop i n A l a s k a d u r i n g 1951, which produced 86 pounds of hemlock seed per a c r e , Garman (1951) found t h a t more than 10 m i l l i o n seeds per acre were r e l e a s e d near A l b e r n i , Van-couver I s l a n d , An e x c e p t i o n a l l y heavy hemlock seed crop was observed by the author i n 1959 a t the U n i v e r s i t y Re-s e a r c h F o r e s t near Haney, An estimated weight of 113 pounds of hemlock seed was produced, per a c r e , i n a young stand of Douglas f i r , hemlock, and cedar, Haig (1941) found that, i n Idaho, western hemlock r e -l e a s e s i t s seeds c o n t i n u o u s l y from midsummer t o the f o l l o w -i n g summer, A l l e n (1958) found t h a t September 15 r e p r e s e n t s approximately the date a t the U n i v e r s i t y F o r e s t i n C o a s t a l B.C. when almost a l l seeds have matured s u f f i c i e n t l y t o germinate and t o s t o r e w e l l . - 4 -A c c o r d i n g t o S i g g i n * s data (1933) the r a t e of f a l l of western hemlock seed was 2.6 f e e t / s e c o n d , which i s the slowest of i t s a s s o c i a t e s o Wiksten (1953) r e p o r t e d t h a t the number of seed caught per acre decreased w i t h i n c r e a s i n g d i s t a n c e from the seed sourceo He a l s o found t h a t l i g h t e s t seed t r a v e l l e d the s h o r t e s t d i s t a n c e s , and the h e a v i e s t , f l e w about 5 c h a i n s * Sutton (1954) s t u d i e d the germination and s u r v i v a l of western hemlock s e e d l i n g s on rotten'wood, l i t t e r , humus, m i n e r a l s o i l and v e r m i c u l i t e , w i t h s p e c i a l a t t e n t i o n t o pH. He found no s i g n i f i c a n t d i f f e r e n c e s i n germi n a t i o n a t t r i b u t a b l e t o seedbed or pH 0 A l l e n (1958) found t h a t seed c o l l e c t e d on September 15, showed a h i g h germinative c a p a c i t y , but a slower r a t e of germination than l a t e r c o l l e c t i o n s . He concluded t h a t s t r a -t i f i c a t i o n reduces the v a r i a t i o n i n r a t e of germination,, B i e n t j e s (1954) i n d i c a t e d t h a t r a t e and amount of ge r m i n a t i o n of seed of western hemlock are h i g h l y v a r i a b l e 8 Of the t h r e e i n c u b a t i o n temperatures used, 20 degrees C. produced the hig h e s t g e r m i n a t i o n percent„ The r e s u l t s r e p o r t e d by Ching (1958) are i n p a r t i a l c o n f l i c t with these of A l l e n and B i e n t j e s i n d i c a t i n g t h a t no p r e s o a k i n g and no s t r a t i f i c a t i o n were c o n s i d e r e d necessary f o r germination t e s t s , but t h a t 20 degrees C„ i n c u b a t i o n temperature a l s o gave the best germin-a t i o n r e s u l t s . One of the most important f a c t o r s f o r s u c c e s s f u l g e r -m i n a t i o n i n the f o r e s t , and i n the n u r s e r y , i s the depth of - 5 -cover* In one study i t was found that, i f the depth of cover exceeded one q u a r t e r of an i n c h , the seeds germinated but they d i d not appear above the ground (Hoffmann 1918) e Olson, S t e a r n s and Nienstaedt (1959) d e s c r i b e d the germin a t i o n p r o c e s s of e a s t e r n hemlock. T h i s process c o r r e s -ponds t o t h a t of western hemlock, as observed by the author,. The r o o t grows at a r a t e of two or t h r e e m i l l i m e t e r s a day, f o r the f i r s t s e v e r a l days, a f t e r which the stem p o r t i o n of the h y p o c o t y l a l s o begins t o grow. Normally, t h e r e i s a pause i n development a f t e r the co t y l e d o n s open, and i t i s at t h i s p o i n t t h a t g e r m i n a t i o n might a r b i t r a r i l y be con-s i d e r e d t o end. Duri n g the e a r l y stages of growth, the lea v e s are formed i n t h r e e s around the stem, a t about the same l e v e l , so t h a t they appear whorled. E a r l y buds on v i g o r o u s shoots o c c a s i o n a l l y f l u s h t w ice i n one growing season (lammas growth), (Walters and Soos, 1961), M o r t a l i t y of s e e d l i n g s begins i n the f o r e s t imme-d i a t e l y a f t e r g e r mination, Haig (1941) p o i n t e d out t h a t e a r l y m o r t a l i t y was caused p r i n c i p a l l y by b i o t i c agents ( i n s e c t s , b i r d s and f u n g i ) and occurred when s e e d l i n g s were s t i l l s u c c u l e n t and t e n d e r . L a t e r l o s s e s , b e g i n n i n g i n l a t e June and e a r l y July, were p r i n c i p a l l y due t o i n s o l a t i o n and drought. He found t h a t i n f u l l s u n l i g h t the s u r f a c e of d u f f becomes much h o t t e r than the s u r f a c e of m i n e r a l s o i l . T h i s caused l e s i o n s a t the ground l i n e on the s u c c u l e n t s e e d l i n g s , producing the death of many, Isaac (1938), found t h a t i n hot weather the temperature of unshaded f i r e - b l a c k e n e d s u r -f a c e s was c o n s i d e r a b l y h i g h e r (seven t o e i g h t e e n degrees F) - 6 -than t h a t of u n d i s t u r b e d m i n e r a l s o i l s a He r e p o r t e d t h a t i n -j u r y began at a s u r f a c e s o i l temperature of 125 degrees F. (which may occur a t an a i r temperature of 85 degrees F ) , Haig (1941) c l a s s i f i e d western white p i n e as one of the deepest r o o t e d and western hemlock as one of the s h a l l o w -e s t r o o t e d s p e c i e s 0 He found t h a t the m o r t a l i t y caused by drought was h e a v i e s t under f u l l shade f o r b o t h s p e c i e s 0 Drought l o s s e s at the f u l l - s u n and part-shade s t a t i o n s would A have been r e l a t i v e l y h i g h e r i f i n s o l a t i o n had not p r e v i o u s l y k i l l e d l a r g e numbers of red cedar and hemlock, Godman and Gregory (1955) found t h a t the d u r a t i o n of r a d i a l growth of western hemlock was 127 days and 133 days, i n 1951 and 1952, r e s p e c t i v e l y , i n A l a s k a , G r i f f i t h E s r e -s u l t s (1959) i n d i c a t e d t h a t the d u r a t i o n of r a d i a l growth f o r the same s p e c i e s , was 155 days and 153 days i n 1954 and 1955* r e s p e c t i v e l y , a t Haney, B,C© O b s e r v a t i o n s of l e a d e r growth were r e p o r t e d by Buckland (195b)o He found t h a t l e a d e r growth s t a r t e d e a r l y i n May and terminated August 25» at Cowichan Lake, Godman and Gre-gory (1955) r e p o r t e d t h a t l e a d e r growth i n A l a s k a began at the end of May and terminated on September 17, i n 1952, W a l t e r s ( I960) p o i n t e d out t h a t the p o i n t of t e r m i n a t i o n of annual growth i n western hemlock i s marked u s u a l l y by an e x t r a l o n g branch immediately below the annual node, We l l n e r (194b) observed t h a t western hemlock responded w e l l i n h e i g h t growth a f t e r a c l e a n i n g i n a mixed s t a n d . Moderately cleaned hemlock s e e d l i n g s had the same average h e i g h t as those on check p l o t s , but the heavy c l e a n i n g r e -suited i n b5 per cent better average height„ G r i f f i t h (1959) found that the average height growth f o r a thinned hemlock stand was s l i g h t l y l e s s than the average height growth of trees on the control area. However, he ob-served that the thinned trees grew i n basal area more than twice as fast as the control trees, Walters, Soos, and Haddock (i960) described western hemlock plus trees at Haney0 The angle of branches i s an important factor f o r plus-tree s e l e c t i o n regardless of tree species (Toda 1957, Zobel I960), Trees with good bole form are frequently rejected i f the angle of branches i s much less than 90 degrees. On the basis of the study reported i n t h i s t h e s i s , i t appears that the s i t e or even the micro-s i t e , has a s i g n i f i c a n t e f f e c t on some external character-i s t i c s of hemlock seedlings. The s i t e s and microsites supporting the hemlock seed-l i n g s studied, are described i n d e t a i l , and the e f f e c t of l i g h t i n t e n s i t y and s i t e q u a l i t y on some external charac-t e r i s t i c s of seedlings, i s discussed within the scope of the study. The relat i o n s h i p between s i t e q u a l i t y and angle of branching receives p a r t i c u l a r emphasis. D E S C R I P T I O N O F S T U D Y A R E A UNIVERSITY OF BRITISH COLUMBIA RESEARCH FOREST The U n i v e r s i t y of B r i t i s h Columbia Research F o r e s t con-s i s t s of 9*774 a c r e s s i t u a t e d i n the F r a s e r V a l l e y , f o u r m i l e s n o r t h of Haney and t h i r t y - f i v e m i l e s eas t of Vancouver, B o C 0 E l e v a t i o n s range from sea l e v e l t o 2,600 f e e t ( U e B 0 C o F o r e s t Committee 1959)o The area i s s i t u a t e d w i t h i n the Southern C o a s t a l S e c t i o n (C^) of Rowe es (1959) F o r e s t Region of Canada and i n the C o a s t a l Western Hemlock Zone of Kra -j i n a 8 s (1959) B i o c l i m a t i c Zones i n B r i t i s h Columbia© The main a s s o c i a t i o n comprises the two c o a s t a l dominants, wes-t e r n red cedar, Thuja p l i c a t a Donn, and western hemlock, Tsuga h e t e r o p h y l l a (Raf.) Sargo, i n combination w i t h Douglas f i r , Pseudotsuga m e n z i e s i i (Mirb) Franco and s c a t t e r e d wes-t e r n white pine Pinus m o n t i c o l a Douglo, P a c i f i c s i l v e r f i r , A b i e s a m a b i l i s (Douglo) Forbo y e l l o w ( o r A l a s k a ) cedar, Chamaecyparis n o o t k a t e n s i s (D« Don) Spach, and S i t k a spruce, P i c e a s i t c h e n s i s (Bongo) C a r r . The western p o r t i o n of the F o r e s t was swept by f i r e i n 1868 and regenerated n a t u r a l l y t o a mixed Douglas f i r , wes-t e r n hemlock and western red cedar stando The e a s t e r n por-t i o n was logged and burned between the y e a r s 1920 and 1931 and now supports mixed stands of Douglas f i r , western hem-l o c k , and western red cedar of v a r i o u s compositions and de-grees of s t o c k i n g . S c a t t e r e d old-growth f o r e s t types are numerous i n the f o r e s t where the f i r e d i d not touch or l i g h t l y - 9 -burned the o r i g i n a l stand. The topographic conditions on the whole area are generally rugged, with numerous rock out-er oppings. Most s o i l s originated from g l a c i a l t i l l . The s o i l i s exceedingly rocky and of a sandy loam texture, with a varying depth, from a few inches to three or more feet ( G r i f f i t h 1960JL C L I M A T E A weather sta t i o n has been maintained at the Forest at an elevation of 550 f e e t , since 1946. The climate i s i n -fluenced by the P a c i f i c Ocean and by the Coast Mountains. The main features of the climate are the mild, wet winters and the comparatively warm, dry summers. Pr e c i p i t a t i o n on the Forest follows, generally, the same pattern as the southern coastal region of B r i t i s h C o l -umbia. The six-month period from October to March, inclusive, i s very moist, having an average p r e c i p i t a t i o n of 11*24 inches per month. But the growing season i s r e l a t i v e l y dry with an average monthly r a i n f a l l of 3.98 inches. Winter p r e c i p i t a t i o n occurs mostly as rain; however, the average snowfall f o r the period 194b - 1957 i s 58 inches. Of the t o t a l p r e c i p i t a t i o n , 40.76 per cent occurs during the winter months, 20.72 per cent during the spring, 11.64 per cent i n the summer and 26.88 per cent i n the autumn. The longest drought since 1946 occurred i n the summer of I960, and lasted f o r f i v e weeks. Temperatures are r e l a t i v e l y mild i n winter and cool i n summer. The average mean temperature f o r the winter months - 10 -i s 34.66 degrees F„ and f o r the summer months, 59<>66 degrees F 0 The average annual mean temperature i s 47 degrees F„ The lowest recorded temperature was minus 5 degrees F G , which occurred i n January 19500 The h i g h e s t recorded temperature of 100 degrees F c occurred i n August I96O0 The average number of f r o s t - f r e e days i s 193 d a y s a The s h o r t e s t p e r i o d occurred i n 1956 wit h 156 f r o s t - f r e e days and the l o n g e s t i n 1947* w i t h 225 d a y s 0 - 11 -THE INFLUENCE OF LIGHT INTENSITY ON HEMLOCK SEEDLINGS„ A representative area i n compartment 3 B (.Figure 1 Appen-dix) was chosen to study the e f f e c t of l i g h t i n t e n s i t y on hemlock seedlings 0 The entire area was burned i n Ibbb1 and reproduced n a t u r a l l y to Douglas f i r , western hemlock and western red cedar 0 Douglas f i r was established f i r s t , f ollowed by western hemlock and western red cedar, as e v i -denced by the younger ages of the l a t t e r two species ( G r i f f i t h 1960) e The average age of the stand, f o r Douglas f i r , at the time the study was made was 77 years s The area i s i n the v i c i n i t y of Plot b ( G r i f f i t h i 9 6 0 ) and has an elevation of 1,100 feet on a southwesterly aspect, with a slope of not more than f i v e per cento The estimated s i t e indices of Dou-glas f i r and western hemlock were 140 feet and 115 f e e t , res-p e c t i v e l y 0 The following c h a r a c t e r i s t i c s were described by G r i f f i t h (1960) o The average depths of s o i l horizons m A % ®Bn and W C M were four, eighteen and eighteen inches, r e s p e c t i v e l y e The depth of horizons was found to be f a i r l y uniform and the s o i l was c l a s s i f i e d as belonging to the imperfectly drained groups of Brown Podsolic s o i l s e The "A2K horizon was grey i n c o l o r with sandy loam texture 0 w B n horizons varied from yellowish brown to dark brown i n color, with conspicuous mottling at the lower l e v e l s 0 The texture was coarse, sandy loam, often containing varied amounts of f i n e gravel« The M C W horizons were of g l a c i a l t i l l formation, l i g h t to dark grey i n color« Texturally they were coarse, sandy loam, and often contained varied amounts of f i n e gravelo - 12 -The 77=year o l d stand near Loon Lake Road was d i s t u r b e d by p a r t i a l l o g g i n g of Douglas f i r and road c o n s t r u c t i o n 0 A v i g o r o u s n a t u r a l r e p r o d u c t i o n p r i n c i p a l l y of western hemlock took p l a c e a l o n g the r o a d s i d e extending i n t o the stand where the l i g h t p e n e t r a t e d from the road and a l s o from the broken canopy of the s t a n d 0 Nine f o u r - m i l a c r e p l o t s were e s t a b l i s h e d t h e r e , under d i f f e r e n t degrees of canopy c l o s u r e ( F i g u r e 1)« The p l o t s u p p o r t i n g no hemlock s e e d l i n g s was e s t a b l i s h e d as a c o n t r o l p l o t . From t h i s p l o t , f o u r o t h e r p l o t s were l o -cated ( P l o t 1, P l o t 2, P l o t 3, and P l o t 4) toward the road, where the c l o s u r e of canopy d e c r e a s e d 0 The d i s t a n c e s between P l o t 1 and P l o t 2, P l o t 2 and P l o t 3* and P l o t 3 and P l o t 4* were 7084 meters, 7<>23 meters and b«,47 meters, r e s p e c t i v e l y . Hemlock s e e d l i n g s on these p l o t s were 11 y e a r s o l d and grew only i n d e c a y i n g wood. P l o t 5 was l o c a t e d i n compartment 3 A, near Loon Lake Camp, where a v i g o r o u s n a t u r a l r e p r o -d u c t i o n grew i n f u l l s u n l i g h t . The p r e v i o u s stand had been harvested i n 1953 because of m i s t l e t o e i n f e c t i o n . E l e v e n -year- o l d s e e d l i n g s growing on d e c a ying wood i n t h i s a r e a , were chosen f o r f u r t h e r study. These were, of course, ad-vance r e g e n e r a t i o n , remaining a f t e r the area was logged i n 1953o The l o c a t i o n of P l o t I , P l o t I I , P l o t I I I and P l o t IV, was the same as d e s c r i b e d f o r P l o t 1, P l o t 2, P l o t 3 and P l o t 4 ( F i g u r e 1), D i s t a n c e s between P l o t I and P l o t I I , P l o t I I and P l o t I I I , and P l o t I I I and P l o t IV, were 5*47 - 13 -meters, 4o47 meters and 3o80 meters, respectively, Seedlings growing on Plot I, Plot I I , Plot III and Plot IV were s i x years old and the roots grew mostly i n MA Q r a horizon. Plot V was located on the same side of Loon Lake Road, i n compart-ment 3 C, where Plantation 27 (Figure 1) was established, to study the growth of hemlock seedlings. The hemlock seed-l i n g s varied from s i x to seven years of age, and grew i n f u l l sunlight. The plots having 11-year-old seedlings were re-corded by arabic numbers, lar g e r numbers representing i n -creased l i g h t i n t e n s i t y . The plots having 6-year-old seed-l i n g s were coded with Roman numbers, the larger numbers re-presenting increased l i g h t i n t e n s i t y . The l i g h t i n t e n s i t y on each plot was measured f o r a 12-hour period, on a cloudy and on a sunny day, with the l i g h t -meter 4o5 feet above ground l e v e l . The lightmeter used was the Brosh type, which gave the i n t e n s i t y i n foot-candles. Since the observation showed that each plot had d i f f e r e n t l i g h t i n t e n s i t i e s , ten seedlings were chosen from each plot f o r further analysis. The posi t i o n of nodes was determined on every seedling with each internode representing one yearns growth. The base and mid-diameter of each internode were measured with a c a l i p e r , obtaining a precision of 1/10 m i l l i -meters. The length of each internode was measured i n m i l l i -meters. Numbers of green and dead branches were counted and recorded f o r every internode, A t o t a l of 100 seedlings was examined and analysed on ten four-milacre p l o t s . - 14 - i THE EFFECT OF MICROSITE ON THE EXTERNAL CHARACTERISTICS OF THREE-YEAR-OLD HEMLOCK SEEDLINGS 0 The area t o r the study or' the i n f l u e n c e of m i c r o s i t e on t h r e e - y e a r - o l d s e e d l i n g s was l o c a t e d i n Compartments IB and IC i n the southern p a r t of the Research F o r e s t , S e e d l i n g s growing i n f u l l s u n l i g h t on f i v e m i c r o s i t e s were s t u d i e d . S e e d l i n g s on m i c r o s i t e s 1 and 4 were p l a n t e d but s e e d l i n g s on m i c r o s i t e s 2, 3, and 5 were n a t u r a l . The d e t e r m i n a t i o n of m i c r o s i t e q u a l i t y based on the t o t a l h e i g h t of s e e d l i n g s , M i c r o s i t e 1, M i c r o s i t e 1 was l o c a t e d i n Compartment 10, t e n meters from the road. U n t i l logged i n 1956, the area supported an old-growth stand c o n s i s t i n g mainly of Douglas f i r . F o l l o w -i n g l o g g i n g the s l a s h was p i l e d and burned. The estimated s i t e index of the p r e v i o u s stand was 160 f e e t f o r Douglas f i r . The ground v e g e t a t i o n s t i l l e v i d e n t on the area was i n d i c a t i v e of the Polystichum f o r e s t type ( K r a j i n a 1^59)• The "A" h o r i z o n s were d i s t u r b e d c o n s i d e r a b l y d u r i n g the l o g g i n g , "B" h o r i z o n s were 70 ce n t i m e t e r s deep, moist, and possessed a h i g h o r g a n i c m a t e r i a l content. The parent m a t e r i a l was g l a c i a l t i l l . The area was f l a t , but w e l l - d r a i n e d . The hemlock seed-l i n g s s t u d i e d were p l a n t e d on the area i n November 1958 as 1 + 1 stock of l o c a l provenance. The p l a n t a t i o n was e s t a -b l i s h e d t o study the e f f e c t of s p a c i n g on v a r i o u s a s p e c t s of growth. - 15 -•/ i M i c r o s i t e 2. The study area was l o c a t e d i n Compartment IB near the North Fork of the A l o u e t t e R i v e r and was p a r t i a l l y logged i n 1955 and c l e a r - c u t i n 1959. The t h i c k n e s s of the "A" horizons, which were only moderately d i s t u r b e d by l o g g i n g , was 12 cen-timeters© The nB" h o r i z o n s were 47 cen t i m e t e r s t h i c k e "Bj™ and M B 2 M h o r i z o n s were separated by seepage w a t e r 0 The m a t e r i a l of the "C n h o r i z o n was d e r i v e d from g l a c i a l t i l l . A study of minor v e g e t a t i o n i n d i c a t e d t h a t the area probably supported the Blechnum f o r e s t type ( K r a j i n a 1959) b e f o r e i t was l o g g e d 0 The area was f l a t but w e l l - d r a i n e d 0 S e e d l i n g s growing on t h i s m i c r o s i t e o r i g i n a t e d n a t u r a l l y . M i c r o s i t e 3. M i c r o s i t e 3 was l o c a t e d adjacent t o M i c r o s i t e 2o S e e d l i n g s growing on t h i s m i c r o s i t e o r i g i n a t e d n a t u r a l l y on wood i n a stage of well-advanced decay© The l o g s were decayed on the s u r f a c e and i n t o the wood f o r a depth of more than 7<>5 c e n t i m e t e r s 0 Two samples of wood from d e c a y i n g D o u g l a s - f i r l o g s were taken t o the F o r e s t Products L a b o r a t o r y , Vancouver, B.C., where the s p e c i f i c g r a v i t y and maximum moisture content a f t e r 12 days'1 s o a k i n g were determined 0 The estimated s p e c i f i c g r a v i t y and the maximum moisture con-t e n t of the two wood samples were 0.146 and 0 o21b, and 826*4 and b3b.b per cent, r e s p e c t i v e l y . S p e c i f i c g r a v i t y and maxi-mum moisture content were, a p p a r e n t l y , i n v e r s e l y r e l a t e d . - lb -M i c r o s i t e 4, The l o c a t i o n , s o i l c h a r a c t e r i s t i c s , and topography of M i c r o s i t e 4 were the same as f o r M i c r o s i t e 10 S e e d l i n g s of l o c a l provenance were p l a n t e d as 1 + 1 s t o c k , and s o i l covered by a s l o w l y decaying mixture of s l a s h and bark of Douglas f i r Q M i c r o s i t e 5«> M i c r o s i t e 5 was l o c a t e d 12 meters n o r t h of M i c r o s i t e 2o The "A" h o r i z o n s were completely removed i n the process of loggingo The "B" h o r i z o n s were 105 c e n t i m e t e r s t h i c k , and con t a i n e d only s l i g h t seepage water, S t o n i n e s s was e s t i -mated at 60 per cent . The area was f l a t but w e l l - d r a i n e d 0 S e e d l i n g s on the area o r i g i n a t e d n a t u r a l l y a f t e r the f i r s t l o g g i n g i n 1955o Examination of the s p e c i e s compo-s i t i o n of the l e s s e r v e g e t a t i o n i n d i c a t e d t h a t t he o r i g i n a l s i t e was r e p r e s e n t a t i v e of the Moss f o r e s t type ( K r a j i n a 1959)o The dominant s p e c i e s of shrubs, f e r n s , herbs, mosses and l i c h e n s growing on m i c r o s i t e s 1, 2 and 5, are l i s t e d i n Table 1, The s e e d l i n g s were chosen randomly from each m i c r o s i t e and the f o l l o w i n g c h a r a c t e r i s t i c s measured: The l e n g t h and base diameter of each i n t e r n o d e , angle of branches on each i n t e r n o d e and the l e n g t h and base diameter of branches. The branch angle was d e f i n e d as the angle between the major a x i s of the stem above the branch and the major a x i s of the branch - 17 -for a distance of 50 millimeters* The instrument used to measure the branch angle was a protractor* One sample branch representing the average length was taken from each internode to measure the length of the seven largest needles* The bark thickness was measured f o r every internode and seedling, with a c a l i p e r * The depths of roots were also re-corded* The average values of the following seedling charac-t e r i s t i c s were obtained f o r each microsite: t o t a l height, base diameter, branch angle of l a s t year's shoots, depth of roots, weight of leaves, root/shoot r a t i o , t o t a l number of branches, number and age of branches on each internode, t o t a l length of branches on each internode, the length of largest needles of each internode per seedling, and bark thickness of each internode* THE INFLUENCE OF SITE ON HEMLOCK SEEDLINGS* The e f f e c t of s i t e on external c h a r a c t e r i s t i c s of hem-lock seedlings was studied i n compartments 2A, 3A, 2B and 3B* Eight p l o t s were established previously to study the growth of Douglas f i r on various s i t e s ( G r i f f i t h I960). Five of these p l o t s , Plot 1, Plot 5, Plot 7, Plot 8, and Plot 4, were logged and the slash and brush were p i l e d and burned. The s i t e indices calculated f o r Douglas f i r ranged from 85 f e e t , to 180 f e e t . S i t e index was determined f o r hemlock by using the equation developed by J.H.G. Smith. (Hemlock SI - 22.34 + 0.663 SI of Douglas f i r . ) (SE £ + 16.4'). The description - 18 -of these plots was reported by G r i f f i t h (19b0). The physical c h a r a c t e r i s t i c s of plots are recorded i n Table 2. The average age of Douglas f i r on Plot 1, Plot 5, Plot 7 and Plot b, was 7b years, whereas on Plot 4> the average age was bO years. The s o i l was f a i r l y uniform on a l l p l o t s and was c l a s s i f i e d as belonging t o the imperfectly drained group of Brown Podsolic s o i l s , with a maximum depth of 60 inches and a minimum depth of two inches. The s o i l on every plot was exceedingly stony, with components varying i n s i z e from f i n e gravel to large boulders. The "Aj" horizons were usually gray i n color and d i s -continuous, with varying thickness. The s o i l was non-f r i a b l e , non-plastic, non-sticky and had a pH range from 3*8 to 4.9. The "B" horizons varied from yellowish-brown to dark brown, generally with conspicuous mottling at the lower l e v e l s . The texture was coarse, sandy loam, often containing f i n e gravel and small concretions. The s o i l was c l a s s i f i e d as f r i a b l e t o firm, non-sticky and with a non-plastic con-sistency. The pH ranged from 4»8 to 5»7» The M C W horizons were of g l a c i a l t i l l o r i g i n , l i g h t t o dark gray i n color, often with reddish mottling. Where the bedrock was close to the surface, the W C M horizon was absent. The maximum t h i c k -ness of the *CI* horizon was 31 inches. The texture was coarse sandy loam, often containing f i n e gravel. The pH of the nC" horizon ranged from 5.3 to 5»9« The depths of s o i l horizons and tree root penetration f o r the p l o t s were summ-arized by G r i f f i t h (I9b0) i n his Table 3. - 19 -Several species - Pseudotsuga menziesii (Mirb) Franco, Tsuga heterophylla (Rat) Sarg, Abies amabilis (Dougl.), Thuja p l i c a t a Donn., Abies grandis Lind., Picea s i t c h e n s i s (Bong), L a r i x decidua M i l l , L a r i x l e p t o l e p i s (Sieb, and Zucc*L, Larix eurolepis (Henry) and Populus spp* - were planted on the logged-over plots as a part of Project 57-10 (U.B.C* Forest Committee, 1959)* The seedlings were planted i n sub-plots 36 feet by 36 f e e t , i n a replicated randomized, block design* Each plot contained two sub-plots f o r every species* Ten hemlock seedlings, selected at random, were measured on each sub-plot, except Plot 4, where only s i x seedlings were available because of high mortality* Height growth was measured f o r every hemlock seedling. The angle of branches on the l a t e s t internode was measured and recorded* For each seedling, the length of the seven largest needles was ob-tained from the samples taken from the l a t e r a l branches of the l a t e s t internode* - 20 -R E S U L T S THE INFLUENCE OF LIGHT INTENSITY ON HEMLOCK SEEDLINGS The amount or* l i g h t The t o t a l amount of l i g h t v a r i e d on each p l o t on sunny days and cloudy days. These d i f f e r e n c e s are n e g l i g i b l e on the c o n t r o l p l o t and on P l o t s I and 1 ( T a b l e s 5 and b ) . F i g u r e s 2 and 3 show t h a t , on sunny days, the l i g h t i n t e n s i t y on each p l o t , except P l o t s V and 5* i n c r e a s e d g r a d u a l l y u n t i l 1400 hours, when they were f r e e of shadow. T h i s r a p i d i n -c r e a s e of l i g h t i n t e n s i t y ceased soon a f t e r 1700 hours, when the sun's rays s t r u c k the p l o t s at an acute a n g l e . The graphs of cumulative l i g h t i n t e n s i t y on a cloudy day ( F i g u r e s 4 and 5) show a more uniform p a t t e r n , because the shadows of the t a l l t r e e s were not obvious i n t h i s case, A g r e a t e r i n -crease of l i g h t i n t e n s i t y began at 1200 hours and l a s t e d u n t i l lbOO hours, when the l i g h t i n t e n s i t y decreased s l o w l y (Table b ) . The r e l a t i v e per cent of l i g h t i n t e n s i t y was obtained f o r each p l o t , by d i v i d i n g the t o t a l v a l u e of l i g h t r e a d i n g s under p a r t i a l shade by the t o t a l v alue r e c e i v e d on open p l o t s . T h i s r e l a t i v e per cent of l i g h t i n t e n s i t y shows gre a t d i f f e r -e n c e s , because the t o t a l of the l i g h t i n t e n s i t y r e a d i n g s was g r e a t e r on open p l o t s on sunny days, than on cloudy days (Tab l e s 5 and b ) . The r e l a t i v e per cent of the cumulative l i g h t r e a d i n g s on cloudy days (Table o) i s used i n t h i s t h e s i s f o r comparisons between v a r i o u s s e e d l i n g c h a r a c t e r i s t i c s on the d i f f e r e n t p l o t s o - 21 -f This measurement or' l i g h t i n t e n s i t y i s preferred because the shadows of trees were minimized under these conditions 0 The average r e l a t i v e percentages of l i g h t i n t e n s i t y f o r Plots I, I I , I I I , IV, 1, 2, 3, and 4, were 13°59, 31c4b, 45o42, 56,33, 10,32, 22,72, 42,54, and 55*90 per cent res-pectively (Table b). The influence of l i g h t i n t e n s i t y on t o t a l height of seedlings. The data (Tables 7 and 8) and graphs (Figures t> and 7) show that there i s a great difference i n t o t a l height be-tween those seedlings which had grown i n the open and those which had grown under the shade of forest canopy. The aver-age height of 11-year-old seedlings i s 37&0 millimeters on Plot 5 while seedlings growing under a l i g h t i n t e n s i t y , 10,32 per cent of that i n the open on Plot 1 (Table b), show an average height of 307 millimeters. The e f f e c t of l i g h t i n -t e n s i t y on t o t a l height i s the same on six-year-old seed-l i n g s as on 11-year-old seedlings. The average t o t a l height of hemlock seedlings grown i n the open on Plot V i s 1617,0 millimeters while seedlings grown i n an average r e l a t i v e l i g h t i n t e n s i t y of 13»59 per cent on Plot I have an average t o t a l height of 133ol millimeters (Tables 9 and 10)o The influence of l i g h t i n t e n s i t y on the age t o reach breast height o It i s obvious from the data presented i n Tables 7, 8, 9, and 10, and from Figures b and 9 .that seedlings grown under d i f f e r e n t l i g h t i n t e n s i t i e s w i l l reach breast height at d i f f -erent ages within s i m i l a r s i t e s . Open grown hemlock seed-l i n g s reached breast height at s i x years, while seedlings - 22 -growing on Plot 4 with a r e l a t i v e l i g h t i n t e n s i t y of 55*90 per cent needed eight years to grow to breast height. Seedlings growing on Plot 3 grew i n a r e l a t i v e l i g h t i nten-s i t y of 42,54 per cent and needed 9°5 years to reach breast height o The e f f e c t of l i g h t i n t e n s i t y on diameter growth. Diameter growth showed a response to increased l i g h t i n t e n s i t y s i m i l a r to that of height growth. The average base diameter of 11-year-old seedlings growing under f u l l l i g h t on Plot 5 i s 51o91 millimeters. The average base diameters of seedlings grown on Plots 4* 3s 2,and 1 are 29.16, 15»95> 7.5,and 2,44 millimeters respectively (Tables 7 and 8 ) , The average base diameters of six-year-old seedlings growing on Plots 5* 4* 3 S 2 and 1 are 25 .70, 7 .17, 2 , 8 0 , 2 o 0 3 , and 1,3b millimeters respectively (Tables 9 and 1 0 ) , The graphs of cumulative mid-diameter of internodes show the same trend (Figures 8 and 9) as the graphs of cumulative periodic l i g h t - i n t e n s i t y measurements (Figures 2, 3» 4> and 5 ) 0 The comparison of the mid-diameters of the l a s t y e ar 8s internodes shows a tendency to decrease from Plot 5 to Plot 1, The mid-diameters of seedlings on Plot 5 , 4* 3 y 2, and 1 were 5 , 1 , 2 , 4 5 , 1,82, 1,11 and 0 o 7 5 millimeters respectively. The mid-diameters of l a s t year's shoots of seedlings on Plot V, IV, I I I , I I and I were 4 . 3 5 , 1,80, 0 . 7 0 , 0.59 and 0 ,50 m i l l -meters respectively. - 2 3 -The i n f l u e n c e of l i g h t i n t e n s i t y on d e n s i t y of f o l i a g e 0 The average t o t a l number of green branches of 1 1-year-o l d s e e d l i n g s on P l o t 5 * 4 , 3 s 2 and 1 was 1 3 3 * 5 , 1 0 4 , 6 , 7 7 , 4 , 34* 5 and 8,6 r e s p e c t i v e l y * The average t o t a l number of green branches of s i x - y e a r - o l d s e e d l i n g s on P l o t s V, IV, I I I , I I and I was 8 9 . 5 , 4 1 * 0 , 1 6 . 6 , 8 * 0 and 3 d r e s p e c t i v e l y ( T a b l e s 7, 8 , 9 and 1 0 ) , The graphs of cumulative number of green branches f o r both ages show a s i m i l a r t r e n d t o the graphs of cumulative l i g h t i n t e n s i t y ( F i g u r e s 1 0 and 1 1 ) o L i g h t i n t e n s i t y and form q u o t i e n t * T a b l e s 7, 8 , 9 , and 10 show t h a t the form q u o t i e n t of the f i r s t i n t e r n o d e i s s i m i l a r f o r a l l p l o t s * (Form q u o t i e n t was d e f i n e d as the r a t i o between the middle diameter and base diameter of the i n t e r n o d e ) * The d i f f e r e n c e i s e v i d e n t when the average form q u o t i e n t of the l a s t y e a r ' s i n t e r n o d e i s compared between p l o t s . The average form q u o t i e n t s f o r t r e e s of P l o t s i , 2 , 3 , 4,and 5 are 0 * 8 , 0 . 7 5 , 0 o 7 6 , and 0 * 6 3 r e s p e c t i v e l y . , S e e d l i n g s from P l o t s I , I I , I I I , IV and V have an average form q u o t i e n t of 0*82, 0*76, 0 * 7 8 , 0 . 7 8 s a n d 0,68 r e s p e c t i v e l y . The average form q u o t i e n t showed a t e n -dency t o decrease w i t h i n c r e a s e d l i g h t . N a t u r a l p r u n i n g and l i g h t i n t e n s i t y . Dead branches were not found on s i x - y e a r - o l d s e e d l i n g s i n P l o t s I t o V ( T a b l e s 9 and 1 0 ) . The average number of dead branches on P l o t s 1 , 2, 3 , 4 , a n d 5 i s 0,2, 1 * 5 , 5 , 0 , 6 . 4 , and 5 , 0 r e s p e c t i v e l y ( T a b l e s 7 and 8 ) , S e e d l i n g s growing - 24 -on the h e a v i l y shaded P l o t 1 were almost f r e e of dead branches having been pruned n a t u r a l l y on the f i r s t f i v e i n t e r n o d e s 0 In c o n t r a s t , the number of dead branches on s e e d l i n g s on P l o t s 2, 3* and 4 i n d i c a t e d t h a t n a t u r a l p r u n i n g on the f i r s t f i v e i n t e r n o d e s was only beginnings S e e d l i n g s growing i n the f u l l l i g h t of P l o t 5 were s t i l l i n the v e r y e a r l y s t a g e s of n a t u r a l p r u n i n g w i t h dead branches on the f i r s t f o u r i n t e r n o d e s o n l y 0 THE EFFECT OF MICROSITE ON THE EXTERNAL CHARACTERISTICS OF THREE-YEAR OLD HEMLOCK SEEDLINGS 0 T o t a l heighto The average t o t a l h e i g h t s of s e e d l i n g s growing on M i c r o -s i t e 1, 2, 3* 4, and 5 are 74bs2, 73bs2, 620o9, 522,7 and 4b9«4 m i l l i m e t e r s r e s p e c t i v e l y ( T a b l e s 11, 12, 13* 14 and 15)o S t u d e n t 8 s t - t e s t was a p p l i e d t o ev a l u a t e the d i f f e r e n c e s between m i c r o s i t e s o No s i g n i f i c a n t d i f f e r e n c e s were found between M i c r o s i t e s 1 and 2, 3 and 4* and 4 and 5e S i g n i f i c a n t d i f f e r e n c e s e x i s t e d at the 0 o 0 5 - p e r - c e n t l e v e l between M i c r o -s i t e s 1 and 3, and 2 and 30 H i g h l y s i g n i f i c a n t d i f f e r e n c e s were observed a t the 0o01 l e v e l between t o t a l h e i g h t s of s e e d l i n g s on M i c r o s i t e s 1 and 4* 1 and 5* 2 and 4* 2 and 5* and 3 and 5 (Table 17)o The average t o t a l h e i g h t of seed-l i n g s of each m i c r o s i t e showed a tendency t o decrease from M i c r o s i t e 1 t o 5» ( F i g u r e 12)0 Base Diameter 0 The average base diameter of s e e d l i n g s i s d i f f e r e n t f o r each m i c r o s i t e o The average base diameters on M i c r o s i t e s 1, 2, 3, 4 and 5 are llo44* b o09, 7olb, b«53, and 5o95 m i l l i -m eters, r e s p e c t i v e l y o Student*s t - t e s t was used t o ev a l u a t e - 25 -the d i f f e r e n c e s i n base diameter f o r each m i c r o s i t e , No s i g n i f i c a n t d i f f e r e n c e s were found between v a l u e s f o r M i c r o -s i t e s 2 and 3, 3 and 4, 3 and 5, and 4 and 5° H i g h l y s i g n i -f i c a n t d i f f e r e n c e s e x i s t a t the 0,01 l e v e l between M i c r o -s i t e s 1 and 2, 1 and 3; 1 and 4, 1 and 5, 2 and 4, and 2 and 5 (Table 18) 0 The average base diameter of s e e d l i n g s grown on each m i c r o s i t e decreases g r a d u a l l y from M i c r o s i t e 1 t o M i c r o s i t e 5 ( F i g u r e 13)• Weight of roots» The average oven-dry weight of r o o t s of hemlock seed-l i n g s on the d i f f e r e n t m i c r o s i t e s d i d not f o l l o w the same d e c r e a s i n g p a t t e r n as observed f o r t o t a l h e i g h t and base diametero The average weight of r o o t s f o r M i c r o s i t e s 1, 4, 3, 2, and 5 ( i n d e c r e a s i n g order) was 12,7, 4*32, 4°21, 3<>75 and 2098 grams r e s p e c t i v e l y ( F i g u r e 14) » The e x p l a n -a t i o n of t h i s order i s t h a t s e e d l i n g s growing on M i c r o s i t e s 1 and 4 were p l a n t e d a r t i f i c i a l l y and they had a b e t t e r developed ro o t system than s e e d l i n g s o r i g i n a t i n g n a t u r a l l y . The f a c t t h a t s e e d l i n g s on M i c r o s i t e 2 had l e s s average weight of r o o t s than on M i c r o s i t e s 3 and 4 excluded the need f o r s t a t i s t i c a l e v a l u a t i o n of m i c r o s i t e d i f f e r e n c e s based on weight of r o o t s . Depth of r o o t s . Western hemlock i s known as a t y p i c a l l y s h a l l o w - r o o t e d s p e c i e s . However, the e f f e c t of d i f f e r e n t m i c r o s i t e s r e s u l t e d i n d i f f e r e n t depths of r o o t i n g . The average depth of roots, i n d e c r e a s i n g order, i s 220,6, 191,1, 178,7, 133<»0 and 120,4 - 26 -millimeters for Microsites 1, 5* 2, 3 and 4 respectively,, (Figure 15)o Although the contrast between Microsites 1 and 4 i s great, seedlings on both microsites had the same average depth of roots one year before the study was made since they were grown i n the nursery. Root depth for seedlings on Microsite 1 was closely followed by that of seedlings on Microsite 5 which had the lowest rate in height and diameter growth. Weight of needles. The average oven-dry weight of needles of seedlings growing on Microsites 1, 2, 3* 4, and 5 was 15 .b4 , 9o94, 8 .0 , 4<>95 and 5.66 grams respectively (Figure lb)„ The average weight of needles of seedlings follows the same pattern as the average height and average base diameter, with the ex-ception of the values for seedlings of Microsite 5* which have a slightly greater average weight than those on Micro-site 4« Student Bs t-test was applied to evaluate the d i f f e r -ences between microsites. Mo significant differences were found between Microsite 2 and 3, and 4 and 5© Significant differences existed at the 0 . 0 5 level between Microsite 1 and 2, 2 and 5* and 3 and 5» Highly significant differences were' at the 0«01 level between Microsite 1 and 3y 1 and 4* 1 and 5 , 2 and 4, and 3 and 4 (Table 21) 0 Root/Shoot ratio. The average ratio for Microsites 1, 2, 3? 4, and 5 was O03b9, 0.19b, 0.286, 0*432, and 0 o 3 0 7 respectively (Tables 11, 12, 13» 14 and 15)o Microsites in decreasing order of root/shoot ratio are 4S 1* 5* 3* and 2. The results indicate - 27 -that the r a t i o was highest t o r planted seedlings and lowest tor those which originated n a t u r a l l y . Total number of branches. The average t o t a l number of branches f o r Microsites 1, 2, 3, 4 and 5 was 38 ,4, 39o0, 34ol, 30,6 and 31eb respectively (Figure 17)© The decreasing order of Microsites i s 2, 1, 3, 5, and 4° The differences between Microsites 1 and 2 and 4 and 5 are so small, that they are n e g l i g i b l e . Gener-a l l y the t o t a l number of branches of Microsites followed the same pattern as t o t a l height and base. The average number of branches by internodes. The average number of branches on the f i r s t internode f o r Microsites 1, 2, 3, 4, and 5 was 2,6, 9o4, 6,9, 5e4, and 6,4 respectively. The small number of branches on seedlings on Microsite 1 i s a re s u l t of poor planting technique and i s discussed l a t e r 0 The average number of branches on the second imternode f o r Microsites 1, 2, 3, 4, and 5 was 18,8, 15o5, 14o0, 16,4, and 13,3 respectively. The average number of branches on the t h i r d internode f o r Microsites 1, 2, 3, 4, and 5 was 17,0, 14.1, 13 o 2, 8,8 and 12,2 respectively (Table 16Jo The average number of branches on the t h i r d internode shows a decrease from Microsite 1 to 5, with the exception of Microsite 5» Average branch angle of internodes. The average branch angle of the f i r s t internode on Micro-s i t e 1, 2, 3, 4, and 5 was 35.00, 47o98s 42,54, 43o70, and 37«81 degrees respectively. The average branch angle of the - 2b -second internode on Microsites 1, 2, 3* 4* and 5 was 49ol5* 48.54* 43o57, 3b003 and 43«79 degrees respectively. The average branch angle of the t h i r d internode on Microsites 1, 2, 3* 4 and 5 was 39.3* 3b82, 34.4* 27 o 8 and 2b09 degrees respectively. The branch angle of the t h i r d internode shows a decreasing pattern from Microsites 1 to 5 (Figure 18)c The differences between microsite were evaluated by using Student's t - t e s t . No s i g n i f i c a n t differences were found between Microsites 1 and 2, 2 and 3* and 4 and 5. Highly s i g n i f i c a n t differences at the 0.01 l e v e l were observed between Microsites 1 and 3, 1 and 4* 1 and 5, 2 and 4* 2 and 5* 3 and 4* and 3 and 5 (Table 19). Average length of largest needles by internodes. The average length of the largest needles on the f i r s t internode of seedlings on Microsites 1* 2, 3* 4* and 5 was 14.9b, 17.36, 16.36, 12.87* and 14.96 millimeters respectively. The average length of the largest needles of the second i n t e r -node on Microsites 1 , 2, 3* 4* and 5 was 17.22, 17.59* 16081, 15«55* and 15.31 millimeters respectively. The average length of the largest needles of the t h i r d internode on Microsites 1, 2, 3* 4, and 5 was 13»79, 12 .26, 11.44* 10.14* and 9.01 millimeters respectively (Figure 19)«> The average length of the largest needles on the t h i r d internode showed the same decreasing pattern from Microsites 1 to 5* as height and average base diameter and branch angle. The differences between microsites based on length of needles were evaluated by using Student's t ~ t e s t 0 No s i g n i f i c a n t differences were - 2 9 -found between M i c r o s i t e s 2 and 3 , and 3 and 4 * S i g n i f i c a n t d i f f e r e n c e s at 0*05 l e v e l were observed between M i c r o s i t e s 1 and 2 , 2 and 4 , and 4 and 5 « H i g h l y s i g n i f i c a n t d i f f e r -ences e x i s t e d a t 0*01 l e v e l between M i c r o s i t e s 1 and 3 , 1 and 4 * 1 and 5 , 2 and 5 , and 3 and 5 (Table 2 0 ) Q The average l e n g t h of branches by internodes o The average l e n g t h of branches on the f i r s t i n t e r n o d e of s e e d l i n g s on M i c r o s i t e s 1 , 2 , 3 , 4 , and 5 was 1 8 0 0 7 3 , 1 5 1 * 9 7 , l 6 l * 8 4 , 1 0 5 * 9 4 and 1 4 5 * 6 m i l l i m e t e r s r e s p e c t i v e l y 0 The average l e n g t h of branches of the second i n t e r n o d e on M i c r o s i t e s 1 , 2 , 3 , 4 , and 5 was 1 7 1*08, 1 2 4 * 3 2 , 1 1 7*83, 87*76, and 87 * 2 5 m i l l i m e t e r s r e s p e c t i v e l y * The average l e n g t h of branches of the t h i r d i n t e r n o d e on M i c r o s i t e s 1 , 2 , 3 , 4 , and 5 was 5 2 * 2 4 , 4 b*48, 1 2*87, 1 8 * 6 7 , and 2 2 * 6 7 m i l l i m e t e r s r e s p e c t i v e l y ( F i g u r e 20)* The average base diameter of branches by i n t e r n o d e s * The average base diameter of branches of f i r s t i n t e r n o d e on M i c r o s i t e s 1 , 2 , 3* 4 , and 5 was 2*78, 1 * 7 6 , 1 * 7 8 , 1 * 1 4 , a n d 1*87 m i l l i m e t e r s r e s p e c t i v e l y * The average base diameter of branches of the second i n t e r n o d e on M i c r o s i t e s 1 , 2 , 3 , 4 , and 5 was 2 * 5 4 , 1 * 5 6 , 1 * 3 2 , 1 * 1 5 , and 1*21 m i l l i m e t e r s r e s p e c t i v e l y * The average base diameter of branches of the t h i r d i n t e r n o d e on M i c r o s i t e s 1 , 2 , 3 , 4 , and 5 was 1 * 5 7 , 1 * 1 4 , 0 * 9 2 , 0 * 4 8 , and 0 a 7 1 m i l l i m e t e r s r e s p e c t i v e l y ( F i g u r e 2 1 )o The data of the t h i r d i n t e r n o d e showed s i m i l a r d e c r e a s i n g p a t t e r n from M i c r o s i t e 1 t o 5 as h e i g h t , base diameter, branch angle and l e n g t h of l a r g e s t needles* - 30 -Bark t h i c k n e s s . The average bark t h i c k n e s s of the f i r s t i n t e r n o d e on M i c r o s i t e s 1, 2, 3, 4* and 5 was 1.42, 0 , 8 6 , 0.99, 0.75* and 0. 69 m i l l i m e t e r s r e s p e c t i v e l y . The average bark t h i c k n e s s of the second i n t e r n o d e on M i c r o s i t e s 1, 2, 3* 4 and 5 was 1.18, 0 . 7 5 , 0 .77, 0.58 and 0 o 54 m i l l i m e t e r s r e s p e c t i v e l y . The average bark t h i c k n e s s of the t h i r d i n t e r n o d e on M i c r o -s i t e s 1, 2, 3* 4, and 5 was 0 o 6 l , Q©47, 0 . 5 8 , 0o37^ and 0 o 36 m i l l i m e t e r s r e s p e c t i v e l y (Table 16). THE INFLUENCE OF SITE ON HEMLOCK SEEDLINGS. Height growth. The height growth of hemlock s e e d l i n g s was measured i n growing seasons of 1959 and 19b0 o The h e i g h t growth on P l o t s 1, 5, 7, 8, and 4 was 128.6, 108 . 3 , 108.0, 106 .4 and 44.2 m i l l i m e t e r s i n 1959 r e s p e c t i v e l y . The h e i g h t growth on P l o t s 1, 5, 7, 8, and 4 i n i960 was 307.8, 316 . 9 , 283o4, 256.0, and 64.0 m i l l i m e t e r s r e s p e c t i v e l y (Table 22)o The d i f f e r e n c e s i n h e i g h t growth between p l o t s were a l r e a d y obvious d u r i n g the 1959 growing season, these d i f f e r e n c e s became even g r e a t e r d u r i n g the I960 growing season. Branch a n g l e . The average branch angle of I960 i n t e r n o d e s on P l o t s 1, 5, 7, 8 and 4 was 49o02, 41*01, 39«92, 35»07 and 24.72 de-grees r e s p e c t i v e l y . The d i f f e r e n c e i n branch angle between P l o t s was e v a l u a t e d by u s i n g Student*s t - t e s t . No s i g n i -f i c a n t d i f f e r e n c e was found between P l o t s 5 and 7« H i g h l y s i g n i f i c a n t d i f f e r e n c e s were obtained comparing P l o t s 1 and - 31 -5, 1 and 7, 1 and 8 , 1 and 4, 5 and 8 , 5 and 4, 7 and 7 and 4, and 8 and 4 respectively (Tables 23)© The upper and lower f i d u c i a l l i m i t s were calculated f or each plot at the 0 o 0 1 l e v e l s The values are given i n Table 25o Generally there was no overlapping between plots except i n the case of Plot 5 and Fl o t 7 where the lower l i m i t of Plot 5 over-lapped the upper l i m i t of Plot 7o This f a c t i s understandable because the site-index difference between those pl o t s i s only 6 f e e t , (The exception of t h i s l a t t e r case indicates that the means of Plots 1 , 5, 8 , and 4 are derived from a heterogeneous population) 0 The upper and lower f i d u c i a l l i m i t s were plotted over the s i t e i n d i c e s , The c o r r e l a t i o n e x i s t i n g between plot s i t e index and average branch angle was found to be l i n e a r , The co r r e l a t i o n c o e f f i c i e n t i s 0 o 9 8 4 , which indicates a highly s i g n i f i c a n t r e l a t i o n between s i t e index (X) and branch angle (Y) c (Correlation c o e f f i c i e n t i s s i g n i f i c a n t f o r 3 Df at the 0 , 0 1 l e v e l at 0,959)o The calc u l a t e d equation of the l i n e i s Y <=> 0 , 3 7 4 X =5*88 and i s i l l u s t r a t e d i n Figure 22, Length of the largest needles. The average length of needles of the lybO internode on Plots 1, 5, 7, 8 and 4 was l b , 7 4 , 1 3 * 7 6 , 14,17, 12,68 and 8 , 1 4 respectively. The differences between plots were eva-luated s t a t i s t i c a l l y by using Student's t ~ t e s t . No s i g n i -f i c a n t differences were found between Plots 5 and 7« Highly s i g n i f i c a n t differences existed between Plots 1 and 5, 1 and 7, 1 and 8 , 1 and 4, 5 and 8 , 5 and 4, 7 and 8 , 7 and 4, and 8 and 4 (Table 24)«. The upper and lower f i d u c i a l l i m i t s were - 32 -c a l c u l a t e d at the 0 o 0 1 l e v e l . These v a l u e s d i d not o v e r l a p except i n the case of P l o t 5 and 7o The upper l i m i t of P l o t 7 w i t h a v a l u e of 1 4 « 6 7 was h i g h e r than the lower l i m i t of P l o t 5 w i t h a v a l u e of 1 3 o 3 1 « T h i s o v e r l a p p i n g i s due t o the f a c t t h a t the d i f f e r e n c e between s i t e i n d i c e s was only 6 f e e t (Table 2 6 ) 0 The upper and lower f i d u c i a l l i m i t s were p l o t t e d over the c o r r e s p o n d i n g s i t e index of each p l o t . The c o r r e l a t i o n between average l e n g t h of l a r g e s t needles (Y) and s i t e i n d i c e s ( X ) appears t o be l i n e a r . The c o r r e l a t i o n c o e f f i c i e n t was h i g h l y s i g n i f i c a n t w i t h a v a l u e of 0 , 9 8 8 , The c a l c u l a t e d e q u a t i o n of l i n e i s Y = 0 , 1 3 2 X - 2 , 3 8 , U s i n g the equations based on needle l e n g t h i t was poss-i b l e t o determine the unknown s i t e i n d i c e s f o r M i c r o s i t e s 1 t o 5« The d i r e c t r e l a t i o n s h i p between branch angle and needle l e n g t h and e i t h e r of these c h a r a c t e r i s t i c s and s i t e i n dex i s shown i n Table 2 7 o In M i c r o s i t e 5 the average branch angle was g r e a t e r than i n " i c r o s i t e 4 , w h i l e the average l e n g t h of the l a r g e s t needles was s i g n i f i c a n t l y l e s s . The r e l a t i o n s h i p s demonstrated f o r M i c r o s i t e s 1 t o 4 become obscured f o r M i c r o s i t e 5 . I t i s d i f f i c u l t t o o f f e r a r e a -s o n a b l e e x p l a n a t i o n f o r t h i s v a r i a b i l i t y . - 33 -D I S C U S S I O N THE INFLUENCE OF LIGHT INTENSITY ON HEMLOCK SEEDLINGS. Baker (1950) had t h i s t o say: "The f o r e s t may be looked upon as a c e l l u l o s e f a c t o r y i n which water and carbon d i o x i d e are used t o make wood through the agency of s u n l i g h t , The m i n e r a l n u t r i e n t s and n i t r o g e n o u s compounds are e s s e n t i a l l y o n l y p a r t s of the machinery of the f a c t o r y 0 By m a n i p u l a t i o n of the l i g h t f a c t o r the r a t e of growth of i n d i v i d u a l t r e e s can be governed, t h e i r form and c h a r a c t e r of the crown can be m o d i f i e d , the s t r e n g t h of the wood can be changed w i t h i n c e r t a i n l i m i t s and the time and amount of r e p r o d u c t i o n can be governed t o a c o n s i d e r a b l e degree." The sun i s the a l l - i m p o r t a n t source of l i g h t f o r p l a n t s i n nature© However s e v e r a l experiments have shown i t i s p o s s i b l e t o grow p l a n t s i n l i g h t which o r i g i n a t e d from other s o u r c e s w i t h the necessary i n t e n s i t y and q u a l i t y (Gerhold 1959, Bourdeau and L a v e r i c k 1958, Kozlowski 1957)o L i g h t i n t e n s i t y may i n f l u e n c e the growth of p l a n t s , f o r m a t i o n of mycorrhizae, and d i s c o l o r a t i o n of f o l i a g e , Kozlowski (1957) r e p o r t e d t h a t Kramer and Decker (1944) found t h a t photo-s y n t h e s i s of l o b l o l l y p i n e i n c r e a s e d w i t h i n c r e a s e of l i g h t i n t e n s i t y up t o f u l l l i g h t , whereas p h o t o s y n t h e s i s of com-p e t i n g hardwoods was g r e a t e s t a t o n e - t h i r d or l e s s of f u l l l i g h t i n t e n s i t y , Bourdeau (1958) s t a t e d t h a t the growth of e a s t e r n hemlock was reduced c o n s i d e r a b l y by exposure t o low l i g h t i n t e n s i t y , Gerhold (1959) r e p o r t e d t h a t r e d u c t i o n i n l i g h t i n t e n s i t y r e s u l t e d i n decreased needle d i s c o l o r a t i o n of S c o t s p i n e . - 34 -The l i t e r a t u r e p r o v i d e s ample evidence of the importance of l i g h t t o f o r e s t growth,, T h i s evidence i s supported by the r e s u l t s of t h i s study which shows t h a t l i g h t i n t e n s x t y has a great i n f l u e n c e on the growth of hemlock s e e d l i n g s 0 S e e d l i n g s growing under the canopy of the stand, r e c e i v e d v a r i o u s amounts of l i g h t on cloudy and sunny d a y s e The l i g h t i n t e n s i t y a l s o v a r i e d a c c o r d i n g t o the time of day. L i g h t i n t e n s i t y i n -creased g r a d u a l l y i n the morning, reached i t s peak at noon, and decreased g r a d u a l l y i n the a f t e r n o o n . The r a t e of change of l i g h t i n t e n s i t y was more g r a d u a l on cloudy days, than on sunny days. The average d a i l y minimum l i g h t i n t e n s x t y f o r a 12 hour p e r i o d was found t o be 117 and l l y - f o o t c a n dles f o r hemlock s e e d l i n g s on a b r i g h t and cloudy day r e s p e c t i v e l y (Tables 5 and b ) 0 E x p r e s s i n g t h i s l a t t e r v a l u e i n per cent of the average l i g h t i n t e n s i t y , i t was found t h a t 10 per cent was the minimum r e l a t i v e i n t e n s i t y f o r s u r v i v a l of hemlock s e e d l i n g s . The average r e l a t i v e l i g h t i n t e n s i t y was c a l c u l a t e d by d i v i d i n g the t o t a l l i g h t (expressed i n f o o t - c a n d l e s ) under the shade by the t o t a l l i g h t on the open a r e a 0 Height growth of hemlock s e e d l i n g s was d i r e c t l y r e l a t e d t o l i g h t i n t e n s i t y up t o f u l l l i g h t i n the open 0 As a consequence of the i n -creased l i g h t i n t e n s i t y , s e e d l i n g s reached b r e a s t h e i g h t at v a r i o u s ages under uniform s i t e c o n d i t i o n s . D i f f e r e n c e s i n age t o b r e a s t h e i g h t of up t o f o u r or more y e a r s were a t t r i -buted t o the i n f l u e n c e of v a r i o u s l i g h t i n t e n s i t i e s . Diameter growth responded t o i n c r e a s e d l i g h t i n t e n s i t y i n the same manner as height growth. Diameter measurements - 35 -from root c o l l a r to terminal shoot were s i m i l a r l y influenced by v a r i a t i o n i n l i g h t i n t e n s i t y . The average number of green branches increased with i n -creased l i g h t i n t e n s i t y . Natural pruning was not evident on six-year-old seedlings and no dead branches were found on such seedlings. Eleven-year-old seedlings, however, showed signs of natural pruning. The rate of natural pruning was inversely related to l i g h t i n t e n s i t y . The taper of seedlings growing slowly under r e l a t i v e l y low l i g h t i n t e n s i t i e s , was apparently less than that of seedlings growing vigorously under r e l a t i v e l y high l i g h t i n t e n s i t i e s . THE EFFECT OF MICROSITE ON THE EXTERNAL CHARACTERISTICS OF THREE-YEAR-OLD HEMLOCK SEEDLINGS. Total height was at a maximum f o r 1 + 1 nursery stock planted on Microsite 1. Although seedlings usually experience a set-back immediately following planting, planted stock on Microsite 1 was larger than natural regeneration on Microsite 2. This difference i s probably explained i n term of the differences of root systems as well as the planting s i t e s . Natural regeneration growing i n decaying wood i n Micro-s i t e 3 was larger and more vigorous than natural regeneration growing i n the poor mineral s o i l of Microsite 5. Hemlock seedlings, representing a homogeneous population when planted, developed, within one year, highly s i g n i f i c a n t differences i n height growth on Microsite 1 compared to Microsite 4. Similar differences were observed f o r base diameter measurements except where highly s i g n i f i c a n t differences were - 3b -demonstrated s t a t i s t i c a l l y between a r t i f i c i a l r e g e n e r a t i o n on M i c r o s i t e 1 and n a t u r a l r e g e n e r a t i o n on M i c r o s i t e 2 . Average base diameter decreased from M i c r o s i t e 1 t o M i c r o s i t e 5 o The data f o r average oven-dry weight of r o o t s i n d i c a t e t h a t a d i f f e r e n t r e l a t i o n s h i p e x i s t s between the v a r i o u s m i c r o s i t e s , than f o r t o t a l h e i g h t and d i a m e t e r s 0 I t i s reasoned t h a t s e e d l i n g s on M i c r o s i t e s 1 and 4 had the bes t average weight of r o o t s because they may have r e c e i v e d more n u t r i e n t s i n the nurs e r y than s e e d l i n g s o r i g i n a t i n g n a t u r a l l y o Another s t r i k i n g r e s u l t was t h a t s e e d l i n g s growing i n w e l l -advanced decaying wood on M i c r o s i t e 3 had a b e t t e r e s t a b l i s h e d and h e a v i e r r o o t system than s e e d l i n g s growing on M i c r o s i t e 2 o T h i s may mean t h a t the top development of young s e e d l i n g s i s not n e c e s s a r i l y a s s o c i a t e d w i t h the weight of r o o t s * Western hemlock i s u s u a l l y c o n s i d e r e d t o be a t y p i c a l l y s h a l l o w - r o o t e d s p e c i e s 0 The r e s u l t of t h i s study i n d i c a t e s t h a t t h i s shallowness i s q u i t e v a r i a b l e between m i c r o s i t e s and i s only r e l a t i v e . S e e d l i n g v i g o r as expressed by hei g h t was not found t o be a s s o c i a t e d w i t h depth of r o o t systems. S e e d l i n g s growing i n m i n e r a l s o i l had a g r e a t e r r o o t depth than those which grew i n decaying wood 0 T h i s f a c t demon-s t r a t e s t h a t the r o o t s i n h a b i t the most f a v o r a b l e zone.: i n the growing media i n terms of m o i s t u r e - h o l d i n g c a p a c i t y and n u t r i -t i v e f a c t o r s . The average weight of needles of s e e d l i n g s v a r i e d w i t h m i c r o s i t e . The weight of needles i s of importance i n p h o t o s y n t h e s i s , and t h e r e f o r e might Of course be expected t o f o l l o w the same t r e n d as hei g h t growth and diameter growth. - 37 -These trends appear to be useful i n evaluating site influences© i f the light factor remains constant. Root/shoot ratio was the highest for the planted seedlings on Microsites 1 and 4« Seedlings on Microsite 2 had the second best height and diameter growth, but the lowest root/shoot ratio, \This fact indicates that the root/shoot ratio i s of less importance in natural wildlings, than in nursery stock). Moreover, the ratio i s not constant but changes from microsite to micro-site and i s not connected with height or diameter growth. Number of branches on seedlings increased with microsite quality. The average number of branches appears to be a good basis to evaluate the vigor and growth potential of young seedlings. The average number of branches per internode followed the same trend. Total number of branches per inter-node increased with site quality. The total number of branches on the f i r s t internode on Microsite 1 was less than on the other microsites. The reason for this i s that the seedlings on Microsite 1 were planted too deep, k i l l i n g the lower branches. It i s recommended that in further studies i n this f i e l d the average number of branches on the last internode offers a convenient measure to estimate the relative vigor (based on total height) of seedlings growing on different micrositeso The average branch angle of internodes decreased with site quality. Branch angles on the f i r s t , second, and third inter-node showed generally similar tendencies. Branch-angle d i f -ferences on the third internode (total age 3) were evaluated - 3 8 -s t a t i s t i c a l l y (Table 19) and i t was found t h a t s e e d l i n g s grow-i n g on d i f f e r e n t m i c r o s i t e s have s i g n i f i c a n t l y d i f f e r e n t branch a n g l e s 0 S e e d l i n g s o r i g i n a t i n g from a reasonably homo-geneous p o p u l a t i o n i n the n u r s e r y and presumably w i t h uniform c h a r a c t e r i s t i c s b e f o r e p l a n t i n g developed d i s s i m i l a r branch a n g l e s a f t e r planting„ S e e d l i n g s growing on M i c r o s i t e 1 had h i g h l y s i g n i f i c a n t d i f f e r e n c e s i n branch angle from s e e d l i n g s grown on M i c r o s i t e 4« T h i s c h a r a c t e r i s t i c of hemlock seed-l i n g s appears t o o f f e r a measure of s i t e q u a l i t y b e s i d e the e v a l u a t i o n based on height growth. The average l e n g t h of l a r g e s t needles of branches on the f i r s t i n t e r n o d e was u n r e l a t e d t o m i c r o s i t e s o The average l e n g t h of l a r g e s t needles on the second i n t e r n o d e decreased w i t h d e c r e a s i n g m i c r o s i t e q u a l i t y . T h i s t r e n d was most e v i -dent on the t h i r d i n t e r n o d e . The s t a t i s t i c a l a n a l y s i s proved t h a t the d i f f e r e n c e s i n needle l e n g t h were s i g n i f i c a n t between m i c r o s i t e s o The average base diameter of branches on the f i r s t , second, and t h i r d i n t e r n o d e showed a tendency t o decrease with d e c r e a s i n g m i c r o s i t e q u a l i t y . S e e d l i n g s on M i c r o s i t e 5 had an only s l i g h t l y h i g h e r average base diameter of branches than those on M i c r o s i t e 4 . The average bark t h i c k n e s s of s e e d l i n g s growing on v a r i o u s m i c r o s i t e s decreased g r a d u a l l y from M i c r o s i t e 1 t o M i c r o s i t e 5 i n d i c a t i n g a c l o s e r e l a t i o n s h i p between bark t h i c k n e s s and m i c r o s i t e q u a l i t y . S e e d l i n g s growing on M i c r o s i t e s 1 and 4 presumably had s i m i l a r bark t h i c k n e s s e s b e f o r e p l a n t i n g but - 3 9 -one year a f t e r p l a n t i n g the average bark t h i c k n e s s of seed-l i n g s growing on M i c r o s i t e 4 decreased 4 7 per cent compared t o M i c r o s i t e 1. T h i s great decrease i n d i c a t e s the apparent importance of m i c r o s i t e as an i n f l u e n c e on the e x t e r n a l c h a r a c t e r i s t i c s of hemlock seedlings„ THE INFLUENCE OF SITE ON HEMLOCK SEEDLINGS. The height growth i n 1959 of w i l d l i n g s p l a n t e d i n A p r i l 1959 on d i f f e r e n t s i t e s r a n g i n g from s i t e i n d i c e s 79 t o 142 f o r hemlock, i n c r e a s e d with s i t e index. Only s l i g h t d i f f e r -e nces i n height growth e x i s t e d between s e e d l i n g s on P l o t s 1 and 5 r e s p e c t i v e l y . C o n s i d e r a b l e d i f f e r e n c e s were e v i d e n t , however, i n comparisons of height growth between s e e d l i n g s on P l o t s 1 and 4 r e p r e s e n t i n g the extremes of s i t e i ndex. The r e s u l t s of p r e l i m i n a r y work on the d i f f e r e n c e s of e x t e r n a l c h a r a c t e r i s t i c s r e v e a l e d t h a t branch angle decreased with s i t e q u a l i t y . These r e s u l t s were supported by compar-i s o n s of measurements of the average branch angle of shoots of the I960 growing season on d i f f e r e n t s i t e s (Table 22). These comparisons r e v e a l marked changes i n s e e d l i n g morphology. A l s o many changes become r e a d i l y apparent w i t h i n two ye a r s a f t e r p l a n t i n g . These c o n c l u s i o n s are b e l i e v e d q u i t e im-por t a n t and are supported s t a t i s t i c a l l y . They are s t a t i s -t i c a l l y s i g n i f i c a n t i n a l l cases where the s i t e - i n d e x d i f f e r -ence exceeded s i x f e e t . Such r a p i d changes i n branch angle, i n p a r t i c u l a r , were unexpected because s e v e r a l authors (Toda 1957, Z o b e l 19b0) r e p o r t e d t h a t the h e r i t a b i l i t y of t r e e h e i g h t , stem t a p e r , s t r a i g h t n e s s of b o l e , crown diameter, - 40 -bark t h i c k n e s s , branch a n g l e , were a l l h i g h . I t should be noted however t h a t these r e p o r t s were n e i t h e r d i r e c t e d s p e c i -f i c a l l y t o western hemlock nor g e n e r a l l y t o s e e d l i n g s . The change i n branch angle i s p o s s i b l y a r e f l e c t i o n of the d i f f -e rent weight of branches. T h i s p o s s i b i l i t y i s strengthened by the f a c t t h a t branch l e n g t h and needle l e n g t h i n c r e a s e d with s i t e o Mergen ( I 9 b 0 j s t a t e d t h a t i f s m a l l changes i n the en-vironment are r e f l e c t e d by pronounced m o d i f i c a t i o n i n the phenotype the t r a i t i s under l o o s e g e n e t i c c o n t r o l 0 I t was f a r beyond the aim of t h i s t h e s i s t o support statements about g e n e t i c f a c t o r s and h e r i t a b i l i t y i n r e s p e c t of western hemlock. The f a c t t h a t s e e d l i n g s changed the branch angle w i t h changes i n s i t e q u a l i t y l e a d s t o the assump-t i o n t h a t the environment may have more i n f l u e n c e i n western hemlock than i n other s p e c i e s , or the h e r i t a b i l i t y of some e x t e r n a l c h a r a c t e r i s t i c s i s l e s s marked i n j u v e n i l e stage than i n l a t e r s t a g e s , The l e n g t h of the l a r g e s t needles on the l a s t y e a r ' s shoots a l s o i n d i c a t e d a h i g h l y s i g n i f i c a n t c o r r e l a t i o n w i t h sxte index, where sxt e xndex d i f f e r e n c e s exceeded s i x f e e t . The change of needle l e n g t h of hemlock s e e d l i n g s growing on v a r i o u s s i t e s emphasized the importance of environmental f a c t o r s o Using the equations based on needle l e n g t h and branch angle i t was p o s s i b l e t o e s timate the unknown s i t e i n d i c e s f o r M i c r o s i t e s 1 to 5 a The p o s s i b l e a p p l i c a t i o n of these r e s u l t s t o s i t e i n dex - 41 -d e t e r m i n a t i o n by u s i n g s e e d l i n g s o l d e r than f o u r y e a r s would r e q u i r e f u r t h e r i n v e s t i g a t i o n . The scope of t h i s study i s c o n f i n e d t o the m a t e r i a l d e s c r i b e d . I t i s emphasized t h a t no attempt i s j u s t i f i e d here t o p r o j e c t the r e s u l t s of t h i s study t o t r e e s o l d e r than f o u r y e a r s . - 42 -C O N C L U S I O N S THE INFLUENCE OF LIGHT INTENSITY ON HEMLOCK SEEDLINGS e The height growth of hemlock s e e d l i n g s was d i r e c t l y r e -l a t e d t o l i g h t i n t e n s i t y o Some d i f f e r e n c e s i n age at b r e a s t h e i g h t w i t h i n p l o t s on s i m i l a r s i t e s were a t t r i b u t e d t o the i n f l u e n c e of l i g h t i n t e n s i t y . Diameters a t i n t e r v a l s from the root c o l l a r t o the t e r -m i n a l shoot were a l s o i n f l u e n c e d by v a r i a t i o n of l i g h t i n -t e n s i t y . Form q u o t i e n t was i n v e r s e l y r e l a t e d t o l i g h t i n -t e n s i t y . The average number of green branches per s e e d l i n g i n -creased w i t h l i g h t i n t e n s i t y o N a t u r a l p r u n i n g was not ev-dent on s i x - y e a r - o l d s e e d l i n g s . N a t u r a l p r u n i n g had s t a r t e d on 11-year-old s e e d l i n g s 0 On 11-year-old s e e d l i n g s the r a t e of n a t u r a l p r u n i n g was i n v e r s e l y r e l a t e d t o l i g h t i n t e n s i t y . THE EFFECT OF MICROSITE ON THE EXTERNAL CHARACTERISTICS OF THREE-YEAR-OLD HEMLOCK SEEDLINGS., The height growth of t h r e e - y e a r - o l d hemlock s e e d l i n g s was i n f l u e n c e d by m i c r o s i t e s 0 D i f f e r e n t environmental con-d i t i o n s r e s u l t e d i n s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s , one y e a r a f t e r p l a n t i n g . S e e d l i n g s growing on de c a y i n g wood had b e t t e r height growth than s e e d l i n g s i n m i n e r a l sub-soil© D i f f e r e n c e s observed i n diameter growth are s i m i l a r t o those observed f o r h e i g h t . The average weight of r o o t s d i d not r e f l e c t the develop-ment of young hemlock s e e d l i n g s . The depth of r o o t s was v a r i a b l e , but was not c o r r e l a t e d w i t h height growth. M i c r o s i t e q u a l i t y (based on t o t a l h e i g h t ) and weight of - 43 -needles of s e e d l i n g s were c l o s e l y c o r r e l a t e d . , Root/shoot r a t i o was not a s s o c i a t e d w i t h m i c r o s i t e quality« The average t o t a l number of branches i n c r e a s e d w i t h i n c r e a s e i n s i t e q u a l i t y , and the same t r e n d was observed between number of branches per i n t e r n o d e on v a r i o u s m i c r o s i t e s 0 The average branch angle per i n t e r n o d e decreased with m i c r o s i t e quality,. Branch-angle d i f f e r e n c e s on the t h i r d i n t e r n o d e were s i g n i f i c a n t even when s e e d l i n g s had been grow-i n g f o r only one y e a r on d i f f e r e n t m i c r o s i t e s o T h i s charac-t e r i s t i c of hemlock s e e d l i n g s appears t o o f f e r a measure of s i t e q u a l i t y o The l e n g t h of the l a r g e s t n eedles on the second and t h i r d i n t e r n o d e was c l o s e l y c o r r e l a t e d with m i c r o s i t e d i f f -erences,, The average base diameter of branches showed a tendency t o decrease w i t h m i c r o s i t e quality„ The average bark t h i c k n e s s of s e e d l i n g s was c o r r e l a t e d w i t h m i c r o s i t e quality« THE INFLUENCE OF SITE ON HEMLOCK SEEDLINGS e The l o c a l environment had a s i g n i f i c a n t e f f e c t on height growth, branch angle, and needle l e n g t h of western hemlock s e e d l i n g s . These d i f f e r e n c e s were not observed when the s i t e -i ndex d i f f e r e n c e d i d not exceed s i x f e e t 0 The s i t e , branch angle, and l e n g t h of l a r g e s t needles had h i g h l y s i g n i f i c a n t c o r r e l a t i o n , , The c a l c u l a t e d equations based on needle l e n g t h and branch angle were n e a r l y i d e n t i -c a l and both c o u l d estimate s i t e index,, - 44 -Table 10 Occurrence or' Ground V e g e t a t i o n on the Three M i c r o s i t e s used t o r Study or' the e f f e c t of M i c r o s i t e s on the E x t e r n a l C h a r a c t e r i s t i c s of Hemlock S e e d l i n g s 0 * M i c r o s i t e Number 1 2 5 Acer c i r c i n a t u m P u r s h 0 X X A g r o s t i s a l b a L e X X A n a p h a l i s margaritacea L e X X X Alnus rubra Bong X Athyrium f i l i x femina (JL») Roth X X B e t u l a p a p y r i p h e r a commutata IRegelj F e r n 0 Var. X X Blechnum s p i c a n t ( L 0 ) Scop 0 X X Cornus canadensis L e X X G a u l t h e r i a s h a l l o n Pursho X X E p i l o b i u m a n g u s t i f o i i u m Lffl X X X Linnaea b o r e a l i s L, X X P o l y t r i c h u m jjuniperum Hedw0 X X P o l y s t i c h u m muni turn ( K a u l f o ) Underw 0 X Populus t r i c h o c a r p a T o r r 0 & Gray X X X Rubus leucodermus Douglo X Rubus s p e c t a b i l i s Pursho X X Rubus v i t i f o l i u s Cham 0 & S c h 0 X X S a l i x Hookeriana B a r r , X S a i i x s i t c h e n s i s Sanson X X Sambucus pubescens (Michx) X S p i r a e a d o u g l a s i i Hook » X Taxus b r e v i f o l i a Nutto X Thuja p l x c a t a Donn a X X Tsuga h e t e r o p h y l l a IRafo) Sarg» X X X Vaccinium p a r v i f o l i u m Smith X X X * P l a n t s were i d e n t i f i e d by L B 0 r l o c z y o - 4 5 -Table 2 . Physical C h a r a c t e r i s t i c s of the Five Plots used for Study of the E f f e c t of Si t e on Hemlock Seedlings, Ch a r a c t e r i s t i c s P L 0 T N U M B E R 1 5 7 8 4 S i t e Index - Feet (for hemlock) 2 1 4 2 128 1 2 2 1 1 5 7 9 Elevation - Feet 6 9 0 1 , 0 0 0 1,080 1 , 1 0 0 1 , 3 7 0 Aspect SW SW SW SE SE Slope - Per cent 13 1 2 1 0 8 1 2 Source: G r i f f i t h B.G. 1900. Growth of Douglas F i r at the University of B r i t i s h Columbia Research Forest as Related to Climate and S o i l . 2. S i t e index was calculated f o r hemlock by using the equation developed by J.H.G. Smith Hemlock SI » 22.34 + 0.663 SI of Douglas F i r (SE + l(>.4«) E ~ - 46 -Table 3. Depths of S o i l Horizons and Tree Root Penetration of Five Plots used f o r Study of the E f f e c t of S i t e on Hemlock Seedlings.*-Plot Average depth of horizons (inches) Depth to Bedrock (inches) Root pentration (inches) No. "A" Max. Min. Ave. Max. Layer of main con-centration 1 3 22 27 60 30 50 28 6-10 5 5 19 18 54 32 37 48 7-16 7 3 19 11 46 22 30 38 2-10 8 4 18 18 42 30 36 38 2-10 4 4 16 5 36 2 20 34 2-10 1. Source: G r i f f i t h B.G. I960. Growth of Douglas F i r at the University of B r i t i s h Columbia Research Forest as related to Climate and S o i l . - 47 -Table 4» Occurrence of Ground V e g e t a t i o n on the F i v e P l o t s used f o r Study of the E f f e c t of S i t e on Hemlock S e e d l i n g s e P L O T N U M B E R 1 5 7 8 4 Acer C i r c i n a t u m P u r s h 0 X A c h l y s t r i p h y l l a D 0 C 0 X Blechnum s p i c a n t (L.) Scop e X X X X ChimaphiJLa__ umbellata (L „) Nutt „ X Cornus canadensis L 0 X Galium b o r e a l e L e X G a u l t h e r i a s h a l l o n Pursh« X X X Goodyera m e n z i e s i i Lindlc X X Gymnocarpium d r y o p t e r i s L« X Linnaea b o r e a l i s L 0 X X Mahonis a q u i f o l i u m f u r s h 6 X M e n z i e s i a f e r r u g i n e a Smith X X Monotropa u n i f l o r a L 0 X OplopanaxlvHorridus (Smith) B. & Ho Pol y s t i c h u m munitum ( K a u l f . ) X Underw» X X X X P t e r i s a q u i l i n a L 0 X X P t e r o s p o r a andromedea N u t t e X Rubus pedatus Smith X X X X Rubus s p e c t a b i l i s Pursho X Sambucus pubescens Michx D X Streptopus a m p l e x i f o l i u s D 8 C 0 X T i a r e l l a t r i f o l i a t a L c X X T r i e n t a l i s l a t i f o l i a Hooka X T r i l l i u m ovaturn Pursh« X X X X Vaccinium membranaceum D o u g l 0 X X X X Vaccinium o v a l i f o l i u m Smith X X X X X Vaccinium p a r v i f o l i u m Smith X V i o l a g l a b e l l a Nutt. X 1. Source* G r i f f i t h B 0 G o 1960 0 Growth of Douglas F i r a t the U n i v e r s i t y of B r i t i s h Columbia Research F o r e s t as r e l a t e d t o C l i m a t e and S o i l . Table 5o The i n f l u e n c e of l i g h t i n t e n s i t y on hemlock s e e d l i n g s L i g h t i n t e n s i t y data on a b r i g h t day f o r 11-and 6-year o l d s e e d l i n g s . Date of Observation J u l y 9, I960, Time of Obser-v a t i o n P l o t V, and . P l o t 5 C o n t r o l P l o t P L 0 T N U M B E R I. I I . XXX o IV. 1 2 3 4 07 00 7500 16 32 90 110 125 28 50 90 125 08 00 9000 24 34 96 125 160 34 60 110 130 0y 00 11250 60 47 100 370 400 70 84 125 165 10 00 11700 96 125 190 230 260 125 195 130 340 11 00 13500 120 70 110 190 400 250 500 520 250 12 00 12900 106 125 IbQ 250 375 190 130 260 500 13 00 12900 70 100 250 750 820 120 190 375 750 14 00 2100 100 180 750 1100 1500 180 375 725 1200 15 00 13950 50 100 250 7800 9000 110 180 750 7500 16 00 21150 240 125 1500 1200 7500 125 200 1500 7500 17 00 3900 110 180 3900 980 500 150 260 500 600 18 00 3600 32 290 450 500 550 180 220 375 450 T o t a l 114450 1024 1408 7846 13605 21590 1562 2373 5460 19520 Average 9537.50 85*33 117o33 653*83 1113*75 1799*16 130*16 197*75 455*0 1626*66 Average r e l a t i v e l i g h t i n -t e n s i t y percent 2 100*0 0 . 8 9 1*23 6.85 11,89 18*86 1.36 2*07 4*77 17*06 1, Measurements were taken i n f o o t - c a n d l e s , 2, C a l c u l a t i o n of the average r e l a t i v e l i g h t - i n t e n s i t y percent d e s c r i b e d on Page 34 o + Foot candle v a l u e s were i d e n t i c a l f o r both p l o t s . Table 6 . The influence of l i g h t i n t e n s i t y oh hemlock seedlings. Light i n t e n s i t y data on a cloudy day (completg overcast) f o r 11-and 6-year-old hemlock seedlings. Date of Observation September 1, I960, Time of Obser-vation F l o t V, and ^ Plot 5 Control plot P L 0 T N U M B E R I * I I , I I I . I V . 1 2 3 4 07 00 700 30 90 110 170 280 64 92 170 280 08 00 y o o 48 170 290 275 375 90 150 250 375 oy oo y«o 64 220 500 490 600 100 200 470 600 10 00 1050 90 155 350 550 725 130 300 520 730 11 00 1100 125 230 450 575 800 200 400 575 800 12 00 1000 90 150 275 650 750 140 250 600 750 13 oo it>50 94 170 550 725 950 125 375 725 950 14 00 1800 110 195 550 800 950 200 400 725 1000 15 00 iy20 b4 155 550 870 950 125 375 725 870 l b 00 1800 94 i y o 500 725 900 125 375 700 900 17 oo 850 bO 120 200 390 450 100 190 375 425 lb 00 185 l b 50 bo 110 120 40 b0 94 110 Total 13935 885 1895 4385 6330 7850 1439 3167 5929 7790 Average l l b l . 2 5 73.75 157.91 365.41 527*50 654ol6 119.91 263.91 494*08 55o90 Average r e l a t i v e l i g h t i n -tensityg 100 b.35 13o59 3lo4b 45*42 56.33 10„32 22.72 42.54 55.90 percent 1 0 Measurements were taken i n foot candles© 2, Calculation of the average r e l a t i v e l i g h t i n t e n s i t y percent described on Page 34. + Foot candle values were i d e n t i c a l f o r both p l o t s s Table 7° The influence of l i g h t i n t e n s i t y on hemlock seedlings 0 Some external c h a r a c t e r i s t i c s of 11-year-old hemlock seedlings on two plot s of various degrees of shade? F l o t C h a r a c t e r i s t i c s No. of 10 seedlings I N T E R N O D E N U M B E R measured on each plot 1 2 3 4 5 6 7 8 9 10 11 Total Average length(mm) Q02 9 .6 11 0 5 13.6 16.3 20.1 26.8 26.7 31«7 57.5 8 4 . 8 307.8 Average middle diameter {mm) 2 e 3 4 2.28 2.17 2.03 1.91 1.81 1.70 1.51 lo29 l o 0 5 0.75 Average form quotient Q096 0.98 0.97 0.9b 0.9b 0.95 0.94 0o92 0*92 0 .88 0.81 Average number of green branches - - 0„6 1.1 0.8 l o 0 1.2 2.8 1.1 8 Qb Average number of dead branches - - 0 . 1 - - 0 . 1 - - - - - 0 o 2 Average length(mm) 25.2 3 0 . 9 33e0 41«4 53.1 47o8 80.2 8 8 . 7 97.7 183.8 169.2 851«0J diameter (nun) 7.05 6.89 6.41 5*90 5.67 5.07 4o40 3<>69 2.98 2.09 1.11 Average form quotient 0 .94 0.98 0.97 0.96 0 o 9 6 0.95 0.94 0.91 0 o 8 9 0.88 0.75 Average number of green branches - 0 . 4 1*3 l o 5 2.0 2.5 3o4 4 o l 4o2 10.5 4o6 34o Average number of dead branches 0 . 4 0 . 2 0.2 0.3 0.3 - - ° « 1 - - - l . i - 51 -o CQ 0 W CD a 0 TJ •H 0 (3 H H JC •o a CQ CD 0) si +* CQ o TJ J* H (0 0 0 V 0 iH u u a CO W CP 0) CD X! >>TJ 1 e H CQ o H 3 0 >. 4=i -ri -P O fe, •H CQ CQ CQ > s O CD •H Cj* •P •P O fi CQ •rl • r i CQ & -P -P CD o X! -P H bt O P. • r i CO H b 0) <S CD Xi U 0 O X5 -P CD H O «0 fi fi e o 0) t* 3 & ce H +5 bi C(=. « e fi © -H • r i rt CD TJ CD B CD JS S CD H CQ CQ H O o O v6 O To" C8 e « e 0 0 © 0 © +3 •O IO CO CO to 0 O N if*. © -o CO H H H CS CO CN NO CO N CO vO O H x> to H © © e e I o o o 0 s © © H •O H o H OO CN o CN 1 ^  to o O N I Ni H ON H H CO O N O N O N ON to CN >* o 00 vO CN IO CN XI O o o o • o 0 0 « o a e 0 O CO o I CN O LO J CO rt © CO l H o H CN CN O H CN ro O © 00 CO to O H CNI OO 30 O CO OO © to O N to o o o o e e o e o I -o -o o «NJ CO 00 o to I 00 IT^  © © O =) iH H H oo H N co CN NO 00 oo to o H CN 00 O. 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CD-^ u CD CQ X! CD \ u CD & CQ X CD — N CD fc, CQ •r l JC •P H S a CD x ; CD CD H S CD X i CD CD H a CD x : CD CD -P CQ Q bOTJ 1 X) O XJ x : s X> 0 XI X! bo TJ a a XJ O Xi X! w oo eg B f l N V u a fi s O C XJ M s c g 0 fi TJ ^ u e s o • r i 3 CD CD-H 0 3 CO fi CD •H 0 3 fi CD - r i o 3 (3 3 fi k • rl H S U -P G U fi CS H a -P fi fi CO H fi -P s fi CO CD H fi CD c Xi CD fi x> U CD fi X) +> TJ O CD CD -P CD CD CD CD Xi CD CD -P CD CD CD CD X) CD CD -P CD CD CD CD Xi O CD bObC CD fcuO-H OO fi U> Qt) Qfi CD W)>ri bo c OO bO bO CD bO-H b& fi bO «0 CD TJ (5 O S cs -a (3 CD CC5 •o C9 «0 a ra CD C3 TJ cs co a «e -P CD CO TJ & CQ CD U U ft u 0 t. CD &t CS U U CS 0 CD U RJ U U CO O & CD U CO eg U CD CD - r i CD 3 CD U CD CD CD CD •rl CD 3 CD t, CD CD CD CD - r i CD 3 CD U CD CD Xi o 3 > > TJ > cr > > > TJ > cr > bD > TJ > > TJ > cr > bO > TJ y H 03 << < < < < < < < < < < < < < *> s 0 9 H » CO -3- to 0» Table 9o The influence of l i g h t i n t e n s i t y on hemlock seedlings 0 Some external c h a r a c t e r i s t i c s of six-year-old hemlock seedlings on two plots of various degrees of shade. Plot No, Cha r a c t e r i s t i c s of 10 seedlings measured on each plot I N T E R N O D E N U M B E R Total 1 2 3 4 5 6 X Q Average length (mm) 9.7 10.0 16.0 27.5 36.1 33.8 133ol Average middle diameter (mm) 1.3 1.20 1.04 0.85 0.66 0.50 Average form quotient 0.95 0.98 0.91 0.85 0.82 0.82 Average number of green branches - 0.1 0.3 3. o 1 1.4 0.2 3.1 Average number of dead branches - - - - - -I I . Average length (mm) 20,5 20.5 30.9 46o5 47*6 41.5 207.5 Average middle diameter (mm) 1.79 1.54 1.36 1.15 0.86 0.59 Average form quotient 0.87 0.93 0.92 0.89 0.81 0.76 Average number of green branches O o l 0.8 1.6 2.6 2.6 0.3 8.0 Average number of dead branches Table 10. The influence of l i g h t i n t e n s i t y on hemlock seedlings Some external c h a r a c t e r i s t i c s of six-year-old hemlock seedlings on three plots of various degrees of shade. Plot No0 C h a r a c t e r i s t i c s of 10 seedlings measured on each plot I N T E R N 0 D E N U M B E R 1 2 3 4 5 6 Total I I I . Average length (mm) 20.1 19.6 31e0 110.7 118,5 80.0 379«9 Average middle diameter (mm) 2.83 2.62 2.46 2.01 1.25 0o7 Average form quotient 0.94 0.96 0.96 0.86 0,79 0o78 Average number of green branches - 0.3 1.7 6.4 7.5 0.7 16.6 Average number of dead branches 0.1 0.2 - - - - 0.3 IV. Average length (mm) 28,8 24.1 31.8 173.0 293.0 318.4 869.1 Average middle diameter (mm) 6.61 6.02 5.72 5.0 3.59 1.8 Average form quotient 0.92 0.95 0.97 0.91 0.82 0,78 Average number of green branches 0.7 0.8 1.9 9.6 16.2 11.8 41.0 Average number of dead branches - - „ => - -V. Average length (mm) 80.5 148.0 122.5 193.0 414.0 659.5 1617,5 Average middle diameter (mm) 23ol 17.8 16.4 13.1 8.95 4.35 Average form quotient 0.90 0.85 0.93 0.89 0.80 0.68 Average number of green branches 6.5 10.0 15.0 10.5 26.0 21.5 89.5 Average number of dead branches — — Table 11. Some external c h a r a c t e r i s t i c s of 10 three-year-old hemlock seedlings on Microsite 1© Cha r a c t e r i s t i c s S E E D L I N G N U M B E R 1 2 3 4 5 6 7 8 9 10 Average Total height (mm) 691 767 73b 681 756 834 725 642 787 841 746.2 Base diameter(mm) 10o3 12.0 11.9 10,7 11.5 14.0 10.9 10.0 11.7 11.4 11.4 Average length of largest needles on 13.8 f i r s t internode 13.6 16.1 19.9 16,9 15.3 11. 8 13.5 15.0 13.2 14.9 Average length of largest needles on second internode 16.0 17©4 23.1 17.7 14.9 16.6 14.5 20.5 14.9 16.1 17.2 Average length of largest needles on 14.87 t h i r d internode 13.36 13.93 15.16 13.37 11.83 12.54 13.26 15.4 14.10 13.7 Total number of branches 46 46 30 31 39 37 33 36 44 42 38.4 Weight of roots (grams) 8.4 15.6 10.6 10.5 14,6 24.0 10.7 11.5 10.5 10.6 12.7 Weight of needles (grams) 13.4 20,6 16,6 13.2 18,4 25.0 13.7 11.4 12.6 13.5 15.8 Root/shoot r a t i o 0„30 0.41 0 , 3 0 0.38 0.38 0.46 0.37 0 o 5 l 0.39 O.36 0.38 Depth of roots(mm) 142 141 146 182 165 201 202 192 595 240 220.6 Double bark th i c k -ness at the middle diameter of f i r s t internode (mm) 1©9 X Q X l o 7 1.1 1.3 1.7 X e 2 1.4 1.4 1.4 1.42 Double bark thick-ness at the middle diameter of second internode (mm) l o 3 0 . 9 X 0 1 1.1 1.2 1.4 X <? 2 1.2 1.3 1.1 1.18 Double bark th i c k -ness at the middle diameter of t h i r d internode (mm) 1*1 0,5 0 . 6 0 . 6 0.5 0.7 0 . 6 0.6 0.3 0 . 6 0.61 Table 12o Some e x t e r n a l c h a r a c t e r i s t i c s of 10 t h r e e - y e a r - o l d hemlock s e e d l i n g s on M i c r o s i t e 2. C h a r a c t e r i s t i c s S E E D L I N G N V M B E R 1 2 3 4 5 6 7 8 9 10 Average T o t a l h eight (mm) 8 1 5 704 8 5 9 8 0 8 7 6 4 6 7 8 6 3 3 7 5 3 6 3 4 6 8 4 7 3 6 . 2 Base diameter(mm) 1 1 c 3 9 . 9 8 . 5 7.6 1 0 . 1 7.0 5 . 6 7.4 6,4 7.1 8 . 0 Average l e n g t h of l a r g e s t needles on f i r s t i n t e r n o d e 1 9*6 1 7 o 8 17.0 1 3 . 2 1 5 . 7 2 0 . 8 1 7 . 0 1 5 . 5 1 9 . 8 1 6 . 8 1 7 . 3 Average l e n g t h of l a r g e s t n eedles on second i n t e r n o d e 1 8 . 2 1 5 . 5 1 8 . 1 1 4 . 5 1 7 . 4 1 9 . 3 1 6 . 8 1 9 . 0 1 9 * 2 1 7 . 4 1 7 . 5 Average l e n g t h of l a r g e s t needles on t h i r d i n t e r n o d e 1 2 . 7 1 2 . 4 9 . 8 3 . X 0 3 1 3 . 8 1 0 . 3 12.3 1 3 . 3 1 3 . 1 1 2 . 2 T o t a l number of branches 4 7 40 4 5 3 6 40 31 3 1 4 9 2 6 4 5 3 9 . 0 Weight of r o o t s (grams) 8 . 7 5 . 1 4 . 0 2.8 4.7 2.7 1.5 2.3 2.1 3 . 6 3.7 Weight of needles (grams) 2 3 . 6 1 3 . 9 1 3 . 0 5.4 10.7 7.4 4.7 6 . 2 4.3 1 0 . 3 9 . 9 4 Root/shoot r a t i o 0 . 2 1 0 . 1 8 0 . 1 7 0 . 2 0 0 . 1 9 0 . 2 1 0 . 1 7 0 . 1 7 0 . 2 3 0 . 2 0 0 . 1 9 Depth of roots(mm) 1 3 5 107 1 4 6 144 204 1 6 5 2 4 2 2 1 2 222 2 1 0 1 7 8 . 7 Double bark t h i c k -ness at the middle diameter of f i r s t i n t e r n o d e (mm) 0 . 6 0 . 8 0 . 9 0.7 1 . 4 0 . 8 0 . 6 0 . 8 1.0 1.0 0 . 8 6 Double bark t h i c k -ness at the middle diameter of second i n t e r n o d e (mm) 0.5 0 . 8 0.5 0.5 1 . 2 0 . 5 0 . 9 0 . 8 0 . 9 0 . 9 0 . 7 5 Double bark t h i c k -ness at the middle diameter of t h i r d intejraode (mm) 0.4 0.4 0 . 6 0.3 0.5 0.3 0 . 5 0.4 0 . 8 0 . 5 0 . 4 7 Table 1 3 o Some e x t e r n a l c h a r a c t e r i s t i c s of 1 0 t h r e e - y e a r - o l d hemlock s e e d l i n g s on M i c r o s i t e 3 « C h a r a c t e r i s t i c s S E E D L I N G N U M B E R Average 1 2 3 4 5 6 7 8 9 1 0 T o t a l height (mm) 4 6 b 4 5 7 5 1 4 617 7 8 3 611 7 5 7 5 2 7 637 840 620.9 Base diameter(mm) 6 . 3 5 . 5 5 . 9 6 . 0 6 . 8 5 . 4 9 . 4 8.0 8.7 9.8 7.18 Average l e n g t h of l a r g e s t n eedles on f i r s t i n t e r n o d e 2 0 . 4 11 . 5 1 4 . 9 1 6 . 4 1 7 . 2 16 . 5 1 6 . 2 14.7 1 7 . 1 16.4 16.1 Average l e n g t h of l a r g e s t needles on second i n t e r n o d e 21 . 5 1 4 . 3 1 7 . 6 17 . 4 13 . 4 14 . 6 16 . 8 15.4 18 o 3 18.3 16.8 Average l e n g t h of l a r g e s t n e e d l e s on t h i r d i n t e r n o d e 1 1 . 3 1 4 . 3 1 0 . 7 10 . 6 1 0 . 6 11 . 6 12.1 1 0.3 1 2 , 1 1 0.4 11.4 T o t a l number of branches 17 23 3 0 3 5 42 4 9 4 0 27 3 5 43 3 4 . 1 Weight of r o o t s (grams) 2 . 8 2 . 5 3 . 6 2 . 4 4 . 3 3 . 7 4 . 3 3 . 5 7 . 1 7.9 4.2 Weight of needles (grams) 7 . 3 4 . 4 5 . 0 6 . 5 8 . 6 6 . 7 4.7 5 . 5 5.0 6.3 8.0 Root/shoot r a t i o 0 . 2 2 0.31 0 . 4 0 0.20 0.26 0 . 3 0 0 . 4 0 0.32 0 . 2 6 0 . 1 7 0.28 Depth of roots(mm) 95 91 1 1 5 1 0 5 5 1 2 4 5 2 2 7 1 5 1 8 5 165 133.0 Double bark t h i c k -ness at the middle diameter of f i r s t i n t e r n o d e (mm) 0 . 9 0 . 9 1.1 0 . 8 0 . 9 0 . 8 1.3 0.8 0.9 1 . 5 0.99 Double bark t h i c k -ness at the middle diameter of second i n t e r n o d e (mm) 0 . 5 0 . 6 0 . 9 0 . 6 0 . 7 0 . 7 1.0 0.7 1.2 0.8 0.77 Double bark t h i c k -ness at the middle diameter of t h i r d i n t e r n o d e (mm) 0 . 6 0 . 4 0 . 6 0 . 4 0 . 7 0 . 5 0.6 0 , 5 0.6 0.9 0 . 5 8 T a b l e 14. Some e x t e r n a l c h a r a c t e r i s t i c s of 10 t h r e e - y e a r - o l d hemlock s e e d l i n g s on M i c r o s i t e 4o C h a r a c t e r i s t i c s S E E D L I N G N U M B E R Average 1 2 3 4 5 6 7 8 9 io 1 T o t a l height (mm) 535 360 530 616 569 476 521 552 475 593 522.7 Base diameter(mm) 6 . 4 5.4 4 . 1 6.0 7.5 6.6 6.8 8.2 6.6 7.7 6.5 Average l e n g t h of l a r g e s t needles on 12.8 f i r s t i n t e r n o d e 13*5 13.0 XX o 7 11.4 13.2 13.2 12.0 14.7 12.4 13.3 Average l e n g t h of l a r g e s t needles on 14.6 16.5 15.5 second i n t e r n o d e l b o 4 13.2 13.1 15.1 17.7 14.2 16.3 18.1 Average l e n g t h of l a r g e s t needles on 8.2 X 2 © X 9.7 10 .1 t h i r d i n t e r n o d e 12e4 12 © 1 10.8 10.4 9.7 7.9 7.8 T o t a l number of 36 branches 25 28 30 35 40 26 29 25 32 30.6 Weight of r o o t s 3.1 5.7 3.6 7.0 4 . 3 (grams) 5.3 3 . 2 2.0 4.7 5.6 3.0 Weight of needles 6.7 3 . 9 7.5 4 . 9 (grams) 5.4 3.6 2.7 4.7 6.6 3.7 3.7 Root/shoot r a t i o 0.43 0.48 0.36 0.47 0.43 0.35 0.43 0.40 0.46 0.46 0.43 Depth of roots(mm) 120 105 130 105 160 132 95 112 145 100 120.4 Double t h i c k n e s s of middle diameter of 0.7 0.75 f i r s t internode(mm) 0 . 9 0 . 6 0.8 0.6 0 . 9 0.8 0.5 0.9 0.8 )ouble bark t h i c k -l e s s at the middle iia m e t e r of second 0.58 Internode (mm) 0.8 0 . 4 0.7 0.5 0.7 0.6 0.5 0.7 0 . 6 0.3 )ouble bark t h i c k -l e s s at the middle iia m e t e r of t h i r d 0.5 0 . 2 0.37 Internode (mm) 0 . 4 0 . 2 0 . 2 0.3 0.5 0.4 0.4 0.6 Table 15o Some external characteristics of 10 three=year-old hemlock seedling on Microsite 5o S E E D L I N G N U M B E R 9 Averag 1 2 3 4 5 6 7 8 1 0 Total height(mm) 4 4 b 5 0 0 4 8 5 4 4 8 5 1 1 5 3 7 4 4 1 3 9 b 5 8 1 5 4 7 4 8 9 . 4 Base diameter(mm) 7„2 bob b . 8 4 . 3 5 . 4 7 . 1 5 . 2 5 .1 5 . 7 5 . 9 5 . 9 Average length of largest needles on f i r s t internode 13.b 1 2 0 3 l b o 4 1 4 . 5 lb.1 l b . 0 1 4 . 4 1 5 . 2 1 5 . 6 1 4 . 9 14.9 Average length of largest needles on second i n t e r n o d e l 5 » 9 13o3 13.8 15.8 lb . 2 14.b 1 5 . 7 15.1 1 5 . 3 1 7 . 0 1 5 . 3 Average length of largest needles on third internode 8 . 2 7 7.29 7*42 7 . 5 4 8 . 4 7 8 . 5 4 7 . 5 4 7.80 8.31 8 . 9 4 8 . 0 1 Total number of branches 2 b 29 3 8 2 4 31 3 7 3 7 2 7 31 3 4 31.6 Weight of roots (grams) 2 e 9 2 o 7 4 . 5 1 . 4 W 0 1 4 . 9 1 .8 2 . 5 3 . 0 4 . 0 2 . 9 Weight of needles (grams) 4 . 1 b o 0 7 . 0 2 . 8 b . 4 9 . 5 4 . 6 3 . 7 5 . 4 7 0 1 5 . 6 Root/shoot ratio 0 . 3 b 0 . 2 4 0 . 3 8 0.28 0 . 2 0 0 . 3 9 0 . 2 4 0 . 4 2 0 o28 0 . 3 4 0 . 3 0 Depth of roots(mm) 1 7 0 170 1 8 5 2 1 5 Ibb 2 3 1 182 1 4 5 2 2 5 2 2 2 1 9 1 . 1 Double thickness at the middle diameter of f i r s t internode(mm)007 0 o 7 O.b 0 . 5 0 . 7 0 . 9 0 . 6 0 . 6 0 . 7 0 . 9 Q.b9 Double thickness at the middle diameter of second internode(mm)0 ob 0 o b 0 . 5 0 . 3 0 . 5 0 . 5 O.b O.b 0 . 7 0 . 5 0 . 5 4 Double bark thickness at the middle diameter of third internode (mm) 0 , 3 0 o 5 0 . 4 0 . 2 0 . 3 0 . 5 0 . 4 0 . 4 0 . 2 0 . 4 0 . 3 b Table l b . C h a r a c t e r i s t i c s or" branches of three-year-old hemlock seedlings i n r e l a t i o n to internode and microsite. (Averages of 10 seedlings per micr o s i t e ) . C h a r a c t e r i s t i c s M I C R O S I T E S CD c u CD •P a H U •rl Average length of branches (millimeters) Average base diameter of branches(millimeters) Average branch angle (degrees) Average number of three-year-old branches Average number of two-year-old branches Average number of one-year-old branches 180.73 1 5 1 . 9 7 l b l . 8 4 1 0 5 . 9 4 145.b 2.78 3 5 . 0 1 . 7 b 4 7 . 9 1.78 42.5 1.14 4 3 . 7 1.87 37.8 1.1 2.b 3.7 1.1 2.0 1.5 b.4 3.0 4.1 4.2 - 0.4 0.2 0.2 0.2 171.08 1 2 4 . 3 2 1 1 7 . 8 3 8 7 . 7 b 8 7 . 2 5 2.54 4 9 . 2 1.5b 4 8 . 5 1.32 4 3 . 5 1.15 3 b . 0 1 . 2 1 4 3 . 8 15.b 9.0 1 1 . 1 13.b b.9 3.2 b.5 2.9 2.8 b.4 52.24 4 b . 4 8 1 2 . 8 7 18.bb 2 2 . b 7 1.57 3 9 . 3 1.14 3 b . 2 0.92 3 4 . 4 0.48 27.8 0 . 7 1 28.9 1 7 . 0 1 4 . 1 13.2 8.8 1 2 . 2 CD GO O C OU CD CD W-P C H Average length of branches (millimeters) Average base diameter of branches (millimeters) Average branch angle (degrees) Average number of two-year-old branches Average number of one-year-old branches CD *s UC •HSH XlCD H-P a H Average length of branches (millimeters) Average base diameter of branches (millimeters) Average branch angle (degrees) Average number of one-year-old branches - 60 -Table 17. Student's t - t e s t values t o r the comparison of the mean t o t a l height of hemlock seedlings on f i v e microsites. Microsite number 1 2 3 4 5 1 X 0.29 2.bl * 7.2b** 9 . 4 4 * * NS 2 X 2.29 * 60b ** 7.66** 3 X 2.02NS 3 . 0 7 * * 4 X 1.14NS 5 X S i g n i f i c a n t t values f o r 18 DF .05 2.101* .01 2.878** Table 18. Student's t - t e s t values f o r the comparison of the mean base diameter of hemlock seedlings on f i v e microsites. Microsite Number 1 2 3 4 5 1 x 6.70** 7.10** 9 . 4 4 * * 11.68** 2 X 1.42NS 3.12** 4.55** 3 X 1.08NS 2.01NS 4 X 1.20NS 5 X S i g n i f i c a n t t values f o r 18 DF .05 2.101 * .01 2.878** - 61 -Table 19* Student's t - t e s t values t o r the comparison of mean branch angle of t h i r d internode of hemlock seedlings on f i v e microsites. Microsite Number 1 2 3 4 5 1 X 1 .57 NS 2.88 ** 6.76** 8.06** 2 X o.78 NS 3.81 3 . 5 7 * * 3 X 3.46** 3.00** 4 X 0.46NS 5 X S i g n i f i c a n t t values f o r 18 DF . 0 5 2.101* . 0 1 2.878** Table 20. Student's t - t e s t values f o r the comparison of mean length of largest needles of t h i r d internode of microsites. hemlock seedlings on f i v e Microsite Number 1 2 3 4 5 1 X 2 . 7 3 * 5 . 7 3 * * 4.10** 14.40** 2 X 1.41 NS 2 . 3 0 * 8.85** 3 X 1.46NS 3 . 1 7 * * 4 X 2.56* 5 X S i g n i f i c a n t t values f o r 18 DF .05 2.101* .01 2.878** - 62 -Table 21. Student's t - t e s t values f o r the comparison of mean oven-dry weight of needles ( i n grams) of hemlock seedlings on f i v e microsites. Microsite number 1 2 3 4 5 1 X 2.56* 4.88** 7 . 7 7 * * 7.27** 2 X 0.42NS 2 . 9 3 * * 2.52* 3 X 2.89** 2.22* 4 X 0.88NS 5 X S i g n i f i c a n t values f o r 18 DF .05 2.101* .01 2.878** - 63 -Table 22. The influence of s i t e on hemlock seedlings. The mean length of largest needles, branch angle of 1960 internode, and height growth of hemlock seedlings. Plot 1 SI 142« Plot 5 SI 128 Plot 7 1 SI 122« Plot 8 SI 115• Plot; SI79 r Mean length of largest needles (millimeters) 16.74 13.76 14.17 12.68 8.11 Mean branch angle I960 internode (degrees) 49.0 41.0 39.9 35.1 27.4 Mean height growth 1959 (millimeters) 128.6 108.3 108.0 106.4 44.2 Mean height growth I960 (millimeters) 307.8 316.9 284 .4 256.0 64.0 Mean length of largest needles based on 7 0 samples on Plot 1 7 0 samples on Plot 5 7 0 samples on Plot 7 7 0 samples on Plot 8 42 samples on Plot 4 Mean branch angle based on 77 samples on Plot 1 94 samples on Plot 5 68 samples on Plot 7 69 samples on Plot 8 18 samples on Plot 4 Mean height growth 1 9 5 9 based on 2 0 seedlings on P l o t l 2 0 seedlings on Plot 5 2 0 seedlings on Plot 7 2 0 seedlings on Plot a 1 2 seedlings on Plot 4 Mean height growth I 9 6 0 based on 4 6 seedlings on P l o t l 4 6 seedlings on Plot 5 29 seedlings on Plot 7 29 seedlings on Plot 8 14 seedlings on P l o t 4 - 64 -Table 23. The influence of s i t e on hemlock seedlings. Student's t - t e s t values f o r comparison of mean branch angle of l a s t year's internode of hemlock seedlings on f i v e plots* Plot Number 1 5 7 8 4 1 x 5.88** 5 . 9 0 * * 8 . 9 4 * * 9 . 3 4 * * 5 X 0.083NS 5.30** 9 . 7 5 * * 7 X 3.84** 8.26** 8 X 5.28** 4 X S i g n i f i c a n t values between DF t .05* t .01** Plots 1 and 5 169 1.974 2.606 Plots 1 and 7 143 1.977 2.614 Plots 1 and 8 144 1.977 2.614 Plots 1 and 4 93 1.986 2.630 Plots 5 and 7 160 1.975 1.608 Plots 5 and 8 161 1.975 1.608 Plots 5 and 4 110 1.982 2.622 Plots 7 and 8 135 1.978 2.613 Plots 7 and 4 84 1.989 2.637 Plots 8 and 4 85 1.989 2.635 - 65 -Table 24* The influence of s i t e on hemlock seedlings* Student's t - t e s t values f o r the comparison of mean length of largest needles of l a s t year's internode of hemlock seedlings on f i v e plots* Plot Number 1 5 7 8 4 1 X 11.92** 9.51** 19.33** 31.85** 5 X X 1.56NS 4.94** 22.48** 7 X X X 6.47** 21.53** 8 X X X X 23.89** 4 X X X X X S i g n i f i c a n t values between DF t.05* t.01** Plots 1 and 5 138 1.977 2.613 Plots 1 and 7 138 1.977 2.613 Plots 1 and 8 138 1.977 2.613 Plots 1 and 4 110 1.982 2.622 Plots 5 and 7 138 1.977 2.613 Plots 5 and 8 138 1.977 2.613 Plots 5 and 4 110 1.982 2.622 Plots 7 and 8 138 1.977 2.613 Plots 7 and 4 110 1.982 2.622 Plots 8 and 4 110 1.982 2.622 - 66 -Table 25» The influence of s i t e on hemlock seedlings* F i d u c i a l l i m i t s at 0.01 l e v e l calculated f o r the mean branch angles (.in degrees) of hemlock seedlings on f i v e p l o t s . Plot number Upper l i m i t Lower l i m i t 1 52.02 46.02 5 42.82 39.20 7 41.88 37.96 8 37.37 32.77 4 28.63 20.81 Table 26. The influence of s i t e on hemlock seedlings. F i d u c i a l l i m i t s at 0.01 l e v e l calculated f o r the mean of largest needles ( i n millimeters) of hemlock seedlings on f i v e p l o t s . F l o t number Upper l i m i t Lower l i m i t 1 17.22 16.26 5 14.21 13.31 7 14.67 13.67 8 12.97 12.39 4 8.54 7.74 - 67 -Table 27. Estimation of hemlock s i t e index of microsites by using needle length and branch angle of hemlock seedlings. Estimated s i t e index Microsite Number 1 2 3 4 5 Based on needle length Based on branch angle 123 112 104 94 78 121 113 107 91 93 68 Fig- 2 Cumulative light intensity of various degrees of shade for 12 hour period of bright day 30,000 2 0 , 0 0 0 k to O o c c a> 10,000 3 o Plot V Plot IV Plot III Plot II Plot I 0700 1000 1400 Time of Observation Control 1800 Line excised because of high value - 6 9 -F i g - 3 C u m u l a t i v e l i g h t i n t e n s i t y o f v a r i o u s d e g r e e s o f s h a d e f o r 12 h o u r p e r i o d o f b r i g h t d a y 30,000r-20,000^ 1 o I I i . c CO c ® « > o 10,000h E o 0700 / P l o t 5 P l o t 4 P l o t 3 . P l o t 2 P l o t I C o n t r o l 1000 1400 Time of Observation 1800 Line excised because of high value - 70 -F i g - 4 C u m u l a t i v e l i g h t i n t e n s i t y o f v a r i o u s d e g r e e s o f s h a d e f o r 12 h o u r p e r i o d o f c l o u d y d a y Time of Observation - 71 -Fig- 5 Cumulative light intensity of various degrees of shade for 12 hour period of cloudy day 15000 CO a> TJ c o o lOOOOh o .o CO c co « o 3 E 3 o 5000 Plot 5 Control Plot 0700 8 I I I 1 10 II 12 13 Time of Observation 14 15 16 17 1800 Fig- 6 Average cumulative length of internodes of 11-year old seedlings on plots of various degrees of shade 4 0 0 0 h Base 5 6 Internodal Number Tip - 73 -Fig- 7 Average cumulative length of internodes of 6-year old seedlings on plots of various degrees of shade Base Internode Number Tip F i g - 8 A v e r a g e c u m u l a t i v e d i a m e t e r o f i n t e r n o d e s o f 1 1 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e Fig- 9 Average cumulative diameter of internodes of 6-year old seedlings on plots of various degrees of shade 4 0 h 30 h Plot / V Base Internode Number Tip F i g - 10 A v e r a g e c u m u l a t i v e n u m b e r o f g r e e n b r a n c h e s o f 1 1 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e F i g - II A v e r a g e c u m u l a t i v e n u m b e r o f g r e e n b r a n c h e s o f 6 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e P l o t V P l o t IV P l o t III P l o t II — P l o t Base Internode Number Tip Fig- 12 Average total height of 3-year old seedlings on various microsites Microsite I Microsite 2 Microsite 3 Microsite 4 Microsite 5 Microsite Microsite 2 Microsite 3 Microsite 4 Microsite 5 Fig- 13 Average base diameter of 3-year old seedlings on various microsites - 79 -14 Average ovendry weight of roots of 3-year old seedlings on various microsites 01 e o o o cr 2 0 E? 5 1 0 T3 C CD > o CD o a> > < I 1 1 l_ Microsites 15 Average depth of roots of 3-year old seedlings on various microsites = 80 -16 Average ovendry weight of needles of 3-year old seedlings on various microsites 1 20 o <»> '5> * 10 >. c Q> > o CT> in 2 f $ 5 • • Microsites 17 Average number of green branches of 3-year old seedlings on various microsites co CP JE o § 40 CD CO JO E Z3 20 -D ,o CD a> o CO > < Microsites - 81 -F i g - 18 T h e a v e r a g e b r a n c h a n g l e o f t h r e e i n t e r n o d e s o n v a r i o u s m i c r o s i t e s 5 0 -< 25 o « o I Microsite I Microsite 2 Microsite 3 Microsite 4 Microsite 5 19 T h e a v e r a g e l e n g t h o f l a r g e s t n e e d l e s o f t h r e e i n t e r n o d e s o n v a r i o u s m i c r o s i t e s CO I 20-9 z •s O £ 10-*- -—. C k. » • E o> — o = a £ > —• < Microsite I I Microsite 2 I Microsite 3 I Microsite 4 I Microsite 5 Legend First internode (from base) f[[Jj Second internode Q Third internode Q 82 -Fig- 20 The average length of branches of three internodes on various microsites 2 0 0 -$ w CQ »*-o 100-o» CO _ l % o E o> — 11 > — < EL Microsite I | Microsite 2 ] Microsite 3 | Microsite 4 | Microsite 5 | Fig- 21 The average base diameter of branches of three internodes on various microsites 3 " •0 s 1 2 ' is 3 Microsite I Microsite 2 Microsite 3 I Microsite 4 Microsite 5 Legend First internode (from baa Second internode Third internode ] ^ F i g 2 2 R e g r e s s i o n l i ne b a s e d o n b r a n c h a n g l e a n d s i t e f o r s t u d y o f t h e i n f l u e n c e o f s i t e o n h e m l o c k s e e d l i n g s 60h 50 a> a> k. « •a » c40l < o c o m O J 2 30 a> > < 20 + I 5 -P 8 4-E q u a t i o n o f l i n e Y = 0 - 3 7 4 X - 5 - 8 8 * Site index is calculated for hemlock 4 + ± 150 140 130 120 110 Site Index 100 90 80 Site index is calculated for hemlock J I I I I I I L. 150 140 130 120 110 100 90 80 Site Index - 85 -B I B L I O G R A P H Y A l l e n G © S 0 1941 L i g h t and temperature as f a c t o r s i n the g e r m i n a t i o n of seed of Douglas f i r (Pseudotsuga t a x i f o l i a ) Lambo B r i t t , F o r , Chron„ 17 (3) (99-109) OOOOOOOOOOO 1958 F a c t o r s a f f e c t i n g the v i a b i l i t y and ger-m i n a t i o n b e h a v i o r of c o n i f e r o u s s e e d 0 For© Chron. 34 (3) (200-298) A l l e n G,S„, I,K 0 Barber and Ian Mahood 1955 - The 1951 a e r i a l b a i t i n g and s e e d l i n g p r o j e c t , Ash R i v e r T r a c t , MacMillan and B l o e d e l L i m i t e d 0 F o r , Chron, 31 (1) (45-59) A t k i n s E,S, 1957 L i g h t measurement i n a study of white pine r e p r o d u c t i on, F o r , Research D i v , T e c h n i c a l Note No, bO, (5-18) Baker S, F r e d e r i c k 1929© E f f e c t of e x c e s s i v e l y h i g h tem-p e r a t u r e s on c o n i f e r o u s r e p r o d u c t i o n . R e p r i n t e d from J o u r n a l of F o r e s t r y , V o l , XXVII, No, 8. (949-974) oooooeooeooe 1948 A s h o r t method of determ i n i n g l e a f area and volume growth i n pine t r e e s , H i l g a r d i a , ( J o u r n a l of A g r i c u l t u r a l S c i e n c e , P u b l i s h e d by the C a l i f o r n i a A g r i c u l t u r a l Experiment S t a t i o n ) (335-355) oo,oooo,oo9« l 9 5 0 P r i n c i p l e s of S i l v i c u l t u r e , McGraw H i l l Book Co,, New York, (125-150) Berntsen C M , 19b0, P l a n t i n g s i t k a spruce and Douglas f i r on decayed wood i n c o a s t a l Oregon 0 Research Note No, 197 (1-5)• U.S,D,A, P a c i f i c Northwest F o r e s t and Range Ex-periment S t a t i o n , P o r t l a n d , Oregon, oooeoo,,oo ,1958 S i l v i c a l c h a r a c t e r i s t i c s of western hem-l o c k , S i l v i c a l s e r i e s No, 3 ( l - l b ) 0 U,S,D 0A, P a c i f i c Northwest F o r e s t and Range Experiment S t a t i o n , P o r t l a n d , Oregon, Bever Dale N, 1954© E v a l u a t i o n of f a c t o r s a f f e c t i n g n a t u r a l r e p r o d u c t i o n of f o r e s t t r e e s i n C e n t r a l Western Oregon, Research B u l l e t i n No, 3 ( l - 4 6 ) e Oregon S t a t e Board of F o r e s t r y , Salem, Oregon, - 86 -B i e n t j e s W. 1954 The e f f e c t s of temperature, seed moisture, and s t r a t i f i c a t i o n on the germination b e h a v i o r of western hemlock s e e d 0 Research Note No. 11 (1-7) U.B.C. F o r e s t Club Research Committee, Vancouver, Bourdeau P,F, and Miriam L, L a v e r i c k 1958 a T o l e r a n c e of p h o t o s y n t h e t i c a d a p t a b i l i t y t o l i g h t i n t e n s i t y i n white p i n e , red p i n e , hem-l o c k and A i l a n t h u s s e e d l i n g s . F o r , Sc, 4 (3) (196-207)O Buckland D.C 1956, Terminal shoot growth of f o u r western c o n i f e r s f o r a s i n g l e growing season. F o r , Chron, 32 (4) (307-399). Ching Te May 1958 Some experiments on the optimum germin-a t i o n c o n d i t i o n s f o r western hemlock. J o u r n a l of F o r e s t r y , 56 (4) (277-279). Dept, of Lands and F o r e s t s , Continuous f o r e s t i n v e n t o r y of B r i t i s h Columbia 1957. Dept, of Lands and F o r e s t s B , C , B,C, F o r e s t S e r v i c e , V i c t o r i a , (1-38), D a l l i m o r e W, & Jackson A, Bruce 1948, A handbook of c o n i f e r a e , Ed. 3. London (682 pp). Downs R.Jo and A,A, P i r i n g e r 1958. E f f e c t s of photoperiod and k i n d of supplemental l i g h t on vege-t a t i v e growth of p i n e s . F o r . Sc. 4 (3) (185-195). D u f f i e l d , J.W, 1955. S e l e c t i n g p l u s t r e e s f o r our seed orchards. I n d u s t r i a l F o r e s t r y A s s o c i a t i o n , P o r t l a n d , Oregon. (15 pages). Garman E,H, 1951 Seed p r o d u c t i o n by c o n i f e r s i n the c o a s t a l r e g i o n of B r i t i s h Columbia r e l a t e d t o d i s s e m i n a t i o n and r e g e n e r a t i o n . T e c h n i c a l P u b l i c a t i o n T, 35 (1-45). Department of Lands and F o r e s t s B r i t i s h Columbia F o r e s t S e r v i c e , V i c t o r i a . Gerhold H.D. 1959 Seasonal d i s c o l o r a t i o n of Scotch pine i n r e l a t i o n t o m i c r o c l i m a t i c f a c t o r s . F o r . Sc. 5 (4) (333-343). Godman R.M. 1953 Seed d i s p e r s a l i n South-east A l a s k a . T e c h n i c a l Note No. 16 (2 pp) of the A l a s k a F o r e s t Research Center U»S.D.A. Juneau, A l a s k a . - 87 -Godman R CM 0 and R,A 0 Gregory 1955o Seasonal d i s t r i b u t i o n of r a d i a l and l e a d e r growth i n the s i t k a spruce western hemlock f o r e s t s of south-eas t Alaskao J o u r n a l of F o r e s t r y 53 (11) ( 8 2 7 - 8 3 5)0 Gregory R©A© 1957 A comparison between l e a d e r growth of western c o n i f e r s i n A l a s k a and Vancouver Islando T e c h n i c a l Notes No c 36 2 p p e A l a s k a F o r e s t Research Center U 0 S 0 D a A « Juneau, Alaska© G r i f f i t h B.G© 1959 The e f f e c t of t h i n n i n g on a young stand of western hemlocks F o r . Chron, 35 (2) (114-133)o 0 9 0 0 0 0 0 0 0 0 I960 Growth of Douglas f i r a t the U n i v e r s i t y of B r i t i s h Columbia Research F o r e s t as r e l a t e d t o c l i m a t e and s o i l . F a c u l t y of F o r e s t r y of U.B.C© F o r e s t r y B u l l e t i n No. 2. (1-58), Vancouver, B 0 C 0 Hacskaylo E, & A,G© Snow, 1959s R e l a t i o n of s o i l n u t r i e n t s and l i g h t t o preval e n c e of mykorhizae on pine s e e d l i n g s 0 S t a t i o n Paper No. 125 (1-13) Northeastern F o r e s t Experiment S t a t i o n U.S.D.A. Upper Darby., Pa. Haig I.T. 1936 F a c t o r s c o n t r o l l i n g i n i t i a l e s t a b l i s h m e n t of western white p i n e and a s s o c i a t e d s p e c i e s . Y a l e U n i v e r s i t y S c h o o l F o r -e s t r y Bui© 41o 149 PPo New Haven, C o n n e c t i c u t . Haig I.T., Kenneth P 0D 0, and R.H. Weidmann 1941o N a t u r a l r e -p r o d u c t i o n i n the western white p i n e t y p e . T e c h n i c a l B u l l e t i n No. 767 (1-98) UsS.D.A. Northern Rocky Mountain F o r e s t and Range E x p e r i m e n t a l S t a t i o n F o r e s t S e r v i c e , Washington, D©C© H a l l i d a y W 0E©D© 1937 A f o r e s t c l a s s i f i c a t i o n f o r Canada. F o r e s t Research D i v i s i o n B u l l e t i n No, 89 (5-27)j F o r e s t r y Branch Canada Depart-ment of Resources and Development, Ottawa. Brown A.W.A. 1943 The d i s t r i b u t i o n of some important f o r e s t t r e e s i n Canada© Ecology© 24 (3) J u l y 1943 (3^4-366) Harlow & H a r r a r 1941 Textbook of Dendrology. McGraw-Hill Book Co© I n c . , New York and London© (503 pp) Hatch A.B. and Doak K 0D. 1933 M y k o r r h i z a l and other f e a t u r e s of the root systems of Pinus.©., J o u r n a l of the A r n o l d Arboretum© Vol© X l V . (85-99) - 8 8 -Hellmers Henry 1959 Hoffmann J.V. 1918 Hough A .F. I960 Isaac LoAo 1928 Hopkins H.G. 1937 eeooooo o o o o o « o X 9 3 ^ Kinghorn J.M. 1 9 5 4 K i t t r e d g e I . 1945 Kozlowski T.T. 1957 K r a j i n a V.I, 1959 Kramer P.J. 1957 P h o t o p e r i o d i c c o n t r o l of bud develop-ment i n c o u l t e r p i n e and bigcone Douglas f i r . F o r . Sc. 5 ( 2 ) (135-141) The importance of seed c h a r a c t e r i s t i c s i n the n a t u r a l r e p r o d u c t i o n of c o n i -f e r o u s f o r e s t s . B u l l e t i n of the U n i v e r s i t y of Minne-s o t a No, 2 ( 8 - 2 5 ) M i n n e a p o l i s . The n a t u r a l r e g e n e r a t i o n of Douglas f i r i n the P a c i f i c Northwest. Department B u l l e t i n No. 1 2 0 0 ( 1 - 5 5 ) U.S.D.A, Washington, D.C. S i l v i c a l c h a r a c t e r i s t i c s of e a s t e r n hemlock. S t a t i o n Paper No. 1 3 2 (1-16), U.S.D.A. Northeastern F o r e s t Experiment S t a t i o n , Upper Darby, P a 0 Measured f l i g h t of seed of Douglas f i r and i t s a s s o c i a t e s . P a c i f i c Northwest F o r e s t and Range Expt. S t a t i o n Unpublished ( 7 Pp) Ty p e w r i t t e n . The f o r e s t s o i l of the Douglas f i r r e g i o n and changes wrought upon i t by l o g g i n g and s l a s h b u r n i n g . R e p r i n t e d from Ecology 1 8 ( 2 ) (264-279) F a c t o r s a f f e c t i n g e s t a b l i s h m e n t of Douglas f i r s e e d l i n g s . C i r c u l a r No. 4 8 6 (1 -45) U.S.D.A., Washington, D.C. The i n f l u e n c e of stand composition on the m o r t a l i t y of v a r i o u s c o n i f e r s , caused by d e f o l i a t i o n by western l o o p e r on Vancouver I s l a n d , B.C. F o r . Chron. 3 0 ( 4 ) ( 3 8 0 - 4 0 0 ) . E s t i m a t i o n of the amount of f o l i a g e of t r e e s and stand s . J o u r n a l of F o r e s t r y 4 3 (1) (905-912) E f f e c t of continuous, h i g h l i g h t i n -t e n s i t y on p h o t o s y n t h e s i s of f o r e s t t r e e s e e d l i n g s . F o r . Sc. 3 ( 3 ) ( 2 2 0 - 2 2 3 ) . B i o c l i m a t i c zones i n B r i t i s h Columbia. U.B.C. B o t a n i c a l S e r i e s . No. 1 ( 1 - 4 5 ) Some e f f e c t s of v a r i o u s combinations of - 89 -ooooeoeoooeoooo.o 1957 of day and n i g h t temperatures and phot o p e r i o d on the hei g h t growth of l o b l o l l y pine s e e d l i n g s . F o r , Sc, 3 U ) (45-54). Kunz R, 1953 Morphologische Untersuchungen i n n a t u r l i c h e n Fohrendickungen 0 M i t t e i l u n g e n der Schweizenschen A n s t a l t f u r das F o r s t l i c h e V e r s y c h -swen 29 12) 1335-402), Le Barron R u s s e l K, 1944 I n f l u e n c e of c o n t r o l l a b l e e n v i r o n -mental c o n d i t i o n s on r e g e n e r a t i o n of j a c k p i n e and b l a c k sp r u c e . R e p r i n t e d from J o u r n a l of A g r i c u l -t u r a l Research, 68 (3) 197-119), Washington, D,C, Ge n e t i c s i n Swedish F o r e s t r y P r a c -t i c e , Stockholm, Sweden 5,173 pages) Some e f f e c t s of l i g h t on growth of white pine seedlings© T e c h n i c a l Note No, 82 (1-18J F o r e s t r y Branch Canada Department of Northern A f f a i r s and N a t u r a l Resources, Ottawa, D i s t r i b u t i o n of r e a c t i o n wood i n e a s t e r n hemlock as a f u n c t i o n of i t s t e r m i n a l growth. F o r , Sc. 4 (2) (98-109) V a r i a t i o n and h e r i t a b i l i t y of p h y s i o l o g i c a l and m o r p h o l o g i c a l t r a i t s i n Norway spruce. F i f t h World F o r e s t r y Congress SP/105-11-UoS.A. (5 pages), A g a l l d i s e a s e of western hemlock i n B r i t i s h Columbia. The F o r e s t r y C h r o n i c l e . 24 (4) (2 pp) Olson J . S e , F o r e s t W. Ste a r n s and H. Nien s t a d t 1959. E a s t e r n hemlock seeds and s e e d l i n g s response t o p h o t o p e r i o d and temperature. B u l l e t i n No. 620 (5 - 7 0 ) . The C o n n e c t i c u t Experiment S t a t i o n , New Haven. Papp L. 1959 The q u a l i t y of s e e d l i n g s and the success of p l a n t i n g . Erdo 8 (9) (335-343)o L i n d q u i s t B. 1948 Logan K.T. 1959 Mergen F. 1958, oooooooooooooooo I960 Nordin V . J . 1950 - 90 -Schubert H 0G C 1952 Germination of v a r i o u s c o n i f e r o u s seeds a f t e r c o l d s t o r a g e 0 F o r e s t Research Note, No, 38 (1-7)« U,S,D,A, C a l i f o r n i a F o r e s t and Range Experiment S t a t i o n , B e r k e l e y , C a l i f o r n i a , S i g g i n s H0W, 1933 D i s t r i b u t i o n and r a t e of f a l l of c o n i -f e r seeds. J o u r n a l Agr, Research 47 (119-128), S i n n o t t W,E, and Wilson K,S, 1955« Botany, P r i n c i p l e s and Problems (60-130), McGraw-Hill Book Co, I n c 0 , New York, Toronto, London 0 Smith D„M, 1951 The i n f l u e n c e of seedbed c o n d i t i o n s on the r e g e n e r a t i o n of e a s t e r n white p i n e . B u l l e t i n 545 (27-56), The C o n n e c t i c u t A g r i c u l t u r a l E x p e r i m e n t a l S t a t i o n , New Haven, Su t t o n R,C, 1954 Some i n f l u e n c e s of seedbed on growth and s u r v i v a l of western hemlock. Research Note No, 10 (1-4)» U,B,C, F o r e s t Club Research Committee, Vancouver, Toda, R, 1957 V a r i a t i o n and h e r i t a b i l i t y of some q u a n t i t a t i v e c h a r a c t e r s i n Cryptomeria. Government F o r e s t E x p e r i m e n t a l S t a t i o n , N i y a z a k i , Japan ( 8 7 - 9 3 ) U,S, Department of A g r i c u l t u r e 19480 Woody p l a n t seed manual, (416 pp)« U 0 S o Government P r i n t i n g O f f i c e , Washington, D,C, Walt e r s J , i 9 6 0 The branch arrangement of western hem-l o c k (Tsuga h e t e r o p h y l l a ) ( R a f 0 ) Sarg, Research Note No, 29 (2 pp) F a c u l t y of F o r e s t r y U « B , C , Vancouver, W a l t e r s J«, J , Soos and P,G0 Haddock I960, The s e l e c t i o n of p l u s t r e e s on the U n i v e r s i t y of B r i t i s h Columbia Research F o r e s t , Haney, B,C, Research Paper No, 33 (1-11), F a c u l t y of F o r e s t r y of U,B,C,, Vancouver, W a l t e r s J , and J 0 Soos 19610 Some o b s e r v a t i o n s on the r e -l a t i o n s h i p of lammas shoots t o the form and growth of D o u g l a s - f i r s e e d l i n g s , ( i n p r e s s ) , - 91 -W e l l n e r C.A. 1946 Wellwood R.W. 1956 OOOOOGOOOOOOOO 1957 Improving composition i n young western white p i n e s t a n d s . Research Note No. 43 (6 pp). U.S.D.A. Northern Rocky Mountain F o r e s t and Range Experiment S t a t i o n , M i s s o u l a , Montana. Some e f f e c t s of dwarf m i s t l e t o e on wes-t e r n hemlock. The F o r e s t r y C h r o n i c l e 32 (3) (282-296) Unpopular s p e c i e s and t h e i r i n c r e a s e d u t i l i z a t i o n . The F o r e s t r y C h r o n i c l e 33 (1) (7-9) . Wiksten A. 1953 Wright J.G. 1943 Zobel B .J. 1957 O . O O O O . . . O O . . 1 9 6 0 Report on r e p r o d u c t i o n s t u d i e s Queen C h a r l o t t e I s l a n d s . Unpublished. Research P r o j e c t No. 8 (1-25) Mimeo-graphed. Measurement of the degree of shading or crown canopy d e n s i t y i n f o r e s t s i t e s . The F o r e s t r y C h r o n i c l e V o l . 19 (3) (183-185). F o r e s t G e n e t i c s and Pulp I n d u s t r y . Tappi V o l . 40 No. 3 (42-44). I n h e r i t a n c e of c e r t a i n important charac-t e r i s t i c s f o r c o n i f e r s . Southern Lumberman (153-158). F i g - 1 L o c a t i o n o f p l o t s e s t a b l i s h e d f o r v a r i o u s s t u d i e s Plot 2 A 2 B L E G E N D Plots for light intensity study Plots for microsite study Plots for study of the effect of site Compartment boundary Scale: | = IOOO 1000 500 0 JL • 1000 I c 2000 I 3000 Feet F i g - 2 C u m u l a t i v e l i g h t i n t e n s i t y o f v a r i o u s d e g r e e s o f s h a d e f o r 12 h o u r p e r i o d o f b r i g h t d a y 30,000k 20,000 CO 0> TJ c o o o o u. CO c cn « 10,000 E 3 o / * / P l o t V P l o t IV P l o t III P l o t II P l o t I C o n t r o l 0700 —1 1 — — i 1 1 P 1000 1400 Time of Observation 1800 Line excised because of high value F i g - 3 C u m u l a t i v e l i g h t i n t e n s i t y o f v a r i o u s d e g r e e s o f s h a d e f o r 12 h o u r p e r i o d o f b r i g h t d a y 30,OOOh 20,000 CO a> o O o o CO c 0) JC > o 10,000 3 £ 3 CJ / / P l o t 5 P l o t 4 P l o t 3 P l o t 2 P l o t I C o n t r o l 0700 1000 1400 Time of Observation 1800 Line excised because of high value F i g - 4 C u m u l a t i v e l i g h t i n t e n s i t y o f v a r i o u s d e g r e e s o f s h a d e f o r 12 h o u r p e r i o d o f c l o u d y d a y Time of Observation Fig-15000 5 Cumulative light intensity of various degrees of shade for 12 hour period of cloudy day Plot 5 Time of Observation Fig 6 Average cumulative length of internodes of 11-year old seedlings on plots of various degrees of shade 40001-£3500 •| 3000 £2500 <D "12000 3 6 o o> o w > < 1500 lOOOh 500 Base Internodal Number Tip F i g - 7 A v e r a g e c u m u l a t i v e l e n g t h o f i n t e r n o d e s o f 6 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e Base Internode Number Tip F i g - 8 A v e r a g e c u m u l a t i v e d i a m e t e r o f i n t e r n o d e s o f 1 1 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e F i g - 9 A v e r a g e c u m u l a t i v e d i a m e t e r o f i n t e r n o d e s o f 6 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e 9 0 r -80h 60h 4 0 h 30h 20r-ioh 3 4 Internode Number F i g - 10 A v e r a g e c u m u l a t i v e n u m b e r o f g r e e n b r a n c h e s o f 1 1 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e F i g - II A v e r a g e c u m u l a t i v e n u m b e r o f g r e e n b r a n c h e s o f 6 - y e a r o l d s e e d l i n g s o n p l o t s o f v a r i o u s d e g r e e s o f s h a d e 90r- P l o t V CO CD x: o c D w m CD CD o 80 70h H _ 60 C D E 50 3 Z CD £ 4 0 a 3 E 3 30 CD cn o CD > 20 10 P l o t IV P l o t III P l o t II P l o t I Base Internode Number Tip F i g - 12 A v e r a g e t o t a l h e i g h t o f 3 - y e a r o l d s e e d l i n g s o n v a r i o u s m i c r o s i t e s F i g - 13 A v e r a g e b a s e d i a m e t e r o f 3 - y e a r o l d s e e d l i n g s o n v a r i o u s m i c r o s i t e s Fig- 14 Average ovendry weight of roots of 3-year old seedlings on various microsites CO E o i _ cr> o cr o '55 l>0 c a> > O CD cn a CD 5 Microsites Fig-15 Average depth of roots of 3-year old seedlings on various microsites CO 0) - t — CD E E 200 o o or £" ioo o CD c n D w. CD > < Microsites F i g - 1 6 A v e r a g e o v e n d r y w e i g h t o f n e e d l e s o f 3 - y e a r o l d s e e d l i n g s o n v a r i o u s m i c r o s i t e s { 20 o £ 10 •D C <u > O co ^ o> in 2 I fl) o • • I 2 3 Microsites F i g 17 A v e r a g e n u m b e r o f g r e e n b r a n c h e s o f 3 - y e a r o l d s e e d l i n g s o n v a r i o u s m i c r o s i t e s CO a> § 40 CO CD E f 20 a .o CT o k. CD > < Microsites F i g - 18 T h e a v e r a g e b r a n c h a n g l e o f t h r e e i n t e r n o d e s o n v a r i o u s m i c r o s i t e s co 50-CD CD i>_ c n CD T3 .CD c n JZ o c D V-CD CD c n D w CD 2 5 -Microsite I | Microsite 2 | Microsite 3 | Microsite 4 | Microsite 5 F i g - 19 T h e a v e r a g e l e n g t h o f l a r g e s t n e e d l e s o f t h r e e i n t e r n o d e s o n v a r i o u s m i c r o s i t e s CO a> | 20-z to CD c n 1 0 -c n oj c L_ co a> - 1 a> J> E c n — a — S £ > >— < Microsite I Microsite 2 I Microsite 3 I Microsite 4 I Microsite 5 Legend First internode (from base) Second internode Q Third internode F i g - 2 0 T h e a v e r a g e l e n g t h o f b r a n c h e s o f t h r e e i n t e r n o d e s on v a r i o u s m i c r o s i t e s 200-10 CP o c o k. m 100-CJ) CO —' "5 a> E u> — 11 > ^  < £ 1 Microsite I | Microsite 2 | Microsite 3 | Microsite 4 | Microsite 5 F i g - 21 T h e a v e r a g e b a s e d i a m e t e r o f b r a n c h e s o f t h r e e i n t e r n o d e s o n v a r i o u s m i c r o s i t e s 3 ' CO a) "5 1 2' co aj E o CL) CO a C O co o CP > < Microsite I I Microsite 2 | Microsite 3 | Microsite 4 | Microsite 5 Legend First internode (from bqse)f|T[| Second internode Third internode F i g - 2 2 R e g r e s s i o n l i ne b a s e d o n b r a n c h a n g l e a n d s i t e f o r s t u d y o f t h e i n f l u e n c e o f s i t e o n h e m l o c k s e e d l i n g s 6 0 -50 to O J a> k_ o> a> T 3 «> c?40 < o c o L_ CD a> o> S 30 a> > < 20 4- I 5 - P * Site index is calculated for hemlock 8 + E q u a t i o n o f l i n e Y * 0 - 3 7 4 X - 5 - 8 8 4 + i 150 140 130 120 110 Site Index 100 90 80 F i g - 2 3 R e g r e s s i o n l i n e b a s e d o n l e n g t h o f n e e d l e s a n d s i t e f o r s t u d y o f t h e i n f l u e n c e o f s i t e o n h e m l o c k s e e d l i n g s + 5 + 7 8 E q u a t i o n o f l i n e Y = 0 1 3 2 X - 2 - 3 8 Site index is calculated for hemlock 150 140 130 120 110 Site Index 100 90 80 F i g - 1 L o c a t i o n o f p l o t s e s t a b l i s h e d f o r v a r i o u s s t u d i e s L E G E N D Plots for light intensity study • Plots for microsite study • Plots for study of the effect of site | | Compartment boundary IOOO 500 0 1000 2000 3000 Scale: l"= IOOO' I 1 1 1 1 1 Feet 

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