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Growth and temperature profile of a Douglas-fir tree Dodic, Dusan 1973

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GROWTH AND TEMPERATURE PROFILE OF A DOUGLAS-FIR TREE by DUSAN DODIC For. Eng. University of Belgrade, 1964  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF FORESTRY  i n the Faculty of FORESTRY  We accept t h i s thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA MAY, 1973  In presenting  this thesis i n p a r t i a l fulfilment of the requirements for  an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t freely available for reference  and study.  I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may by his representatives.  be granted by the Head of my Department or  It i s understood that copying or publication  of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission.  Department of  Sej //•-  The University of B r i t i s h Columbia Vancouver 8, Canada  Date  I  ABSTRACT  This thesis investigated the temperature and growth p r o f i l e of one Douglas-fir tree.  A series of thermocouples located at  different heights and depths was recorder.  Using systematic  period of two years.  connected to one multi-channeled  sampling, data were recorded  Temperatures were analyzed  for a  f o r one summer  and one winter month.  V e r t i c a l d i s t r i b u t i o n of the width of annual rings analyzed  was  for the period of the l a s t 50 years f o r both earlywood  and latewood as well as for t o t a l annual rings.  Basic growth  theories were outlined and the thesis suggests that none of these gives a completely s a t i s f a c t o r y answer.  Possible s i g n i f i c a n c e of  temperature on the v e r t i c a l growth d i s t r i b u t i o n of annual rings was  outlined.  II  TABLE OF CONTENTS  Page ABSTRACT  I  TABLE OF CONTENTS  II  LIST OF TABLES  IV  LIST OF FIGURES  V  ACKNOWLEDGEMENTS  VII  INTRODUCTION  1  LITERATURE REVIEW  2  V e r t i c a l p r o f i l e of a i r and tree temperatures V e r t i c a l growth d i s t r i b u t i o n Bole formation theories  2 4 7  DESCRIPTION OF AREA  10  LOCALITY OF INVESTIGATION  10  CLIMATE OF THE AREA  10  Precipitation Temperature Hours of bright sunshine Climagraphs of the area EQUIPMENT AND SAMPLING  11 12 13 15 19  Equipment  19  Sampling  21  RESULTS V e r t i c a l growth d i s t r i b u t i o n Temperature p r o f i l e of the tree  25 25 34  Ill  TABLE OF CONTENTS (continued) Page DISCUSSION  43  CONCLUSION  59  BIBLIOGRAPHY  61  APPENDIX  64  Climagraphs of the area f o r period 1960-1970  65  I V  LIST OF TABLES  Table  Page  1  Macroclimatic s t a t i s t i c s July 30 to August 25, 1968 (Period 1) recorded at Administration Building.  36  2  Macroclimatic s t a t i s t i c s December 1 to December 29, 1968 (Period 2) recorded at Administration Building.  37  3  F values f o r measurements above the ground, Period 1.  39  4  F values for a l l measurements, Period 1.  40  5  F values f o r Period 2.  41  V  LIST OF FIGURES Figure  Page  1  Form of annual rings f o r suppressed, dominant and open grown tree.  5  2  Variations i n thickness of annual rings at various ages on one plantation grown tree.  6  3  Average p e r c i p i t a t i o n f o r period 1958-1970 at Administration Building Weather Station.  11  4  Maximum, minimum, and average temperatures f o r period 1958-1970 at Administration Building Weather Station.  13  5  Monthly average of hours of bright sunshine recorded at Road E20 (Spur 17).  14  6  Climagraph f o r period 1958-1970, Administration Building Weather Station.  16  7  Climagraph f o r period 1958-1970 Road E20 (Spur 17) Weather Station.  17  8  Relative positions of sensors i n bark, sapwood, and heartwood.  24  9  Average width and v e r t i c a l d i s t r i b u t i o n of earlywood, latewood and t o t a l annual rings for period 1921-1930, 1931-19A0, 1941-1950 and 1951-1960.  26  10  Average width and v e r t i c a l d i s t r i b u t i o n of earlywood, latewood, and t o t a l annual rings for period 1961-1970.  27  11  Width of earlywood, latewood and annual ring 1960 and 1961.  30  12  Width of earlywood, latewood and annual ring 1962 and 1963.  30  13  Width of earlywood, latewood and annual ring 1964 and 1965.  31  14  Width of earlywood, latewood and annual ring 1966 and 1967.  31  -X  VI  LIST OF FIGURES (continued) 15  Width of earlywood, latewood and annual ring 1968 and 1969.  16  Width of earlywood, latewood and annual ring 1970  17  Stem temperature changes on August 1, 1968 at 4.5 f t . above the ground.  18. Stem temperature changes on August 1, 1968 at 45.0 feet above the ground. 19  Stem temperature changes on August 1, 1968 at 85.0 feet above the ground.  20  Stem temperature changes on August 22, 1968 at 4.5 feet above the ground.  21  Temperature of environment on August 1, 1968.  22  Temperature of the bark surface at d i f f e r e n t v e r t i c a l levels on August 1, 1968.  23  Temperature of inside of the bark at d i f f e r e n t v e r t i c a l levels on August 1, 1968.  24  Temperature of the sapwood at d i f f e r e n t v e r t i c a l levels on August 1, 1968.  25  Temperature of the heartwood at d i f f e r e n t v e r t i c a l levels on August 1, 1968.  26  Temperature of the environment on August 22, 1968  27  Temperature of the bark surface at d i f f e r e n t v e r t i c a l levels on August 22, 1968.  28  Temperature of inside of the bark at d i f f e r e n t v e r t i c a l levels on August 22, 1968.  29  Temperature of the sapwood at different v e r t i c a l levels on August 22, 1968.  30  Temperature of the heartwood at different v e r t i c a l levels on August 22, 1968.  VII  ACKNOWLEDGEMENT  I wish to thank Mr. L. Adamovich f o r encouragement and guidance i n this study and Dr. J.H.G. Smith f o r h i s very valuable c r i t i c i s m , suggestions and encouragement, as w e l l as f o r f i n a n c i a l support.  I would also l i k e to express my appreciation to Dr. A.  Kozak f o r h i s advice and assistance with s t a t i s t i c a l analyses, Dr. J . Worrall f o r h i s guidance and c r i t i c i s m , and Dr. V. Heger for h i s valuable suggestions.  I would l i k e to express my  gratitude to Mr. J . Walters f o r h i s encouragement and guidance i n the f i n a l stages of the study, to Mr. R. St. Jean f o r h i s help i n c o l l e c t i n g of data and to Miss B.A. Bilodeau f o r her patience with my handwriting. F i n a l l y , I wish to thank my wife, Jelena f o r her patience and understanding.  1.  INTRODUCTION  In recent years interest i n the microclimate of the forest has been increasing.  Through analysis of the energy budget of the forest,  a l l forms of energy within the system can be traced and located.  The  main source of energy i s solar radiation which takes the form of heat, chemical reactions, e t c . Energy i s transported within the system by conduction, or radiation and, at the same time, transformation of one type of energy to another takes place.  The basic form of energy  within the system, or within the tree as a unit of that system, i s heat.  When solar radiation f a l l s upon a tree, the part of the tree  exposed to this radiation becomes warmer than the surrounding a i r . Heat from exposed parts of the tree i s conducted to the rest of the tree and radiated into the a i r . the lower parts of the tree.  A i r i n return conducts the heat to  The amount of energy stored i n the tree,  i n a unit of time, depends on exposure of the tree to the energy source, solar radiation. Temperature of the a i r does not have a direct e f f e c t on tree form or the structure of the tree but the action of heat i s v i s i b l e on p h y s i o l o g i c a l processes. Depending upon heat conditions, a tree can have an increase, retardation, or complete cessation of physiological activities. F i r s t plant temperature measurements were recorded by Hunter i n 1775.  Since then a large number of measurements have been made on  2.  d i f f e r e n t plants as w e l l as on trees.  Most measurements have been made  on a short term basis and there i s lack of data on temperature and heat d i s t r i b u t i o n covering a period of more than two or three days. In this thesis an attempt i s made to relate the temperature measurements of one Douglas-fir tree near the Administration Building on the University of B r i t i s h Columbia Research Forest, Maple Ridge, B.C., to the growth of annual rings at d i f f e r e n t heights.  Temperature  measurements were recorded f o r two years, and growth d i s t r i b u t i o n within the measured area was analysed.  In a way i t i s a continuation of  Heger's work (1965), who suggested that temperature of the d i f f e r e n t parts of a tree may be one of the important factors i n bole formation.  LITERATURE REVIEW  VERTICAL PROFILE OF AIR AND TREE TEMPERATURE  Knowledge of the a i r temperature i s e s s e n t i a l i n the explanation of many p h y s i o l o g i c a l a c t i v i t i e s such as the flushing of buds, flowering, beginning and ending of growth.  In forestry, where we are dealing with  complex plant communities, with d i f f e r e n t plant temperature requirements, knowledge of v e r t i c a l a i r temperature p r o f i l e i s important. The temperature of the a i r layer near the open ground i s determined by the amount of heat which the surface of the ground absorbs (Geiger, 1950).  Under the forest canopy i s the body of a i r whose properties are  conditioned by the stand.  B a s i c a l l y we have the same case as i n the  3.  open ground but the point of exchange of heat i s raised from the ground to the canopy of the stand.  Consequently during the day, with incoming  radiation, the highest temperature w i l l be i n the upper part of the crowns.  During the night conditions are reversed, the highest temperature  i s under the canopy due to outgoing radiation streams. This was confirmed by Walters (1960) who found that the average a i r temperature i n a Douglas-fir - western hemlock forest at the height of 90 feet was 4°F higher as compared to one foot above the ground. The maximum difference occured late i n the afternoon. In a deciduous forest, a i r temperature at the height of 25m i s higher at a l l times as compared to lm above the ground.  On an average  sunny day the least difference was 0.7°C and maximum was 3.1°C (Heckert 1959).  The author concluded that the difference was caused by openings  i n the canopy of a deciduous forest.  Due to these openings the forest  f l o o r becomes a secondary active surface of heat exchange between a i r and the s o l i d s . The temperatures within the trees are closely related to a i r temperature because they are conditioned by the microclimate of the environment. Heger (1965) found that the bark surface of Douglas-fir trees exposed to direct sun radiation reached a temperature as high as 102F. At the same time a i r temperature was 65-67F.  Temperature of the trees  grown within the stand was 1-2F lower than a i r temperature. Temperatures measured at heights of 0-86 cm. showed that plantationgrown red pine had uniform temperature at 0 cm. except during the night  4.  when i t dropped 3°C.  Temperature at 86 cm. was  a s i n u s o i d i a l wave with  the difference between two extremes of 5.5°C (Herrington, 1969). In general there i s a s c a r c i t y of research on temperatures of the l i v i n g trees.  Despite t h i s s c a r c i t y , one can draw the following  conclusions on the basis of previous  research.  1. Amplitude and time of maximum and minimum temperature change from the surface to the i n t e r i o r of the tree. In the i n t e r i o r of the wood the amplitude i s smaller and the occurrences of maximum and minimum temperatures i s l a t e r than on the surface of the tree  (Herrington,  1969). 2. Temperature of the tree stem varies with height.  The  crown of the tree i s warmer i n the spring and summer and colder i n the f a l l and winter as compared to the base of the tree. 3. Response to temperature changes depends on the s i z e of the tree or the parts of the tree.  VERTICAL GROWTH DISTRIBUTION  The amount of cambial growth, and the d i s t r i b u t i o n of earlywood and latewood along the tree bole, v a r i e s .  It was  found by Hartig,  Onaka, and others that v a r i a t i o n i n thickness of annual rings can be found not only i n dominant but i n suppressed and open grown trees (Farrar, 1961;  Kozlowski, 1971).  Suppressed trees have a maximum  5.  growth of annual r i n g at the upper part of the crown.  Along the bole  the width of annual ring decreases and i n some cases i n the lower part of the bole i t may be missing ( F i g . 1, curve 1) (Farrar, 1961). Dominant trees have a maximum width of annual r i n g i n the upper part of the crown.  Along the bole the width of annual r i n g decreases  and then increases at the base of the tree ( F i g . 1, curve 2). The annual r i n g of an open grown tree has i t s maximum close to the ground ( F i g . 1, curve 3).  cu  u o 60  EC  Width of annual layer  Figure 1.  Form of the annual rings f o r suppressed (1), dominant (2), and open grown tree (3). (From Farrar, 1961).  This was confirmed for Douglas-fir where dominant trees had maximum width of annual layers i n the crown and equal width below the crown.  Xylem production i n the case of suppressed trees  diminished toward the stem base (Kozlowski, 1971).  In a dominant  Douglas-fir tree, open grown, with l i v e crown 94% of the t o t a l height i t was found that the width of the annual rings was uniform except at the top where i t decreased.  A Douglas-fir tree grown i n  crowded conditions with the l i v e crown 39% of the t o t a l height had uneven width of the annual layers.  Thickness of annual rings from  the butt decreased and i n the upper part of the stem increased, with sharp decrease at the top of the tree (Walters, 1962; Heger, 1965). Furthermore, i t i s possible to f i n d two types of v e r t i c a l xylem d i s t r i b u t i o n within the same tree (Farrar, 1961).  8 years 16 years tree free crowns from compet- .closing ition  \ \  Figure 2.  20 years trees crowded  )/ • \  21 years thinning  \  30 years trees crowded  )/ V  width of annual layer  Variation i n thickness of annual rings at various ages on one plantation grown tree (From Farrar, 1961).  7.  Change i n d i s t r i b u t i o n of the width of annual layers can be attributed to stand development and s i l v i c u l t u r a l treatment such as thinning and pruning (Farrar, 1961).  BOLE FORMATION THEORIES  This phenomena was explained by many s c i e n t i s t s who developed several theories.  In the 19th century Theodor Hartig proposed a  n u t r i t i o n a l theory.  This theory explained uneven d i s t r i b u t i o n of  r a d i a l increment along the bole by a v a i l a b i l i t y of food within the tree.  I t was assumed that the quantity of food i s d i r e c t l y related  to the quantity of foliage above the point i n question.  In other  words, maximum r a d i a l growth i s achieved close to the base of the l i v e crown and i t diminishes above and below that point. The conductive theory i s based on the uniform flow of water from the root to the l i v e crown.  Jaccard found that dead branches reduce  the cross-sectional area and the flow of water i n to the crown. Increasing growth i n the area of dead branches occurs i n order to maintain a uniform flow of water because the cross-sectional area i s increased at the same rate at which i t was reduced by the dead branch. The hormonal theory was developed i n 1930 by F.W. Went who i s o l a t e d a substance which was p h y s i o l o g i c a l l y active i n a very small concentration (Farrar, 1961).  The evidence was obtained that the buds  and leaves are the only producers of that substance which i s phytohormone, known as auxin.  Theodor Hartig i n 1853 f i r s t made the observation that  8.  cambial a c t i v i t y started at the base of expanding buds and spread along the branches and bole of the tree (Zimmerman, 1971).  This  was attributed to the presence of auxin which stimulates the d i v i s i o n of cambial c e l l s .  Auxin moves downward from the buds towards the stem  and i n t o i t , activating the cambium i n the spring.  This downward  movement through the phloem may l a s t f o r a few weeks.  I t has been  proved by experiments that buds need not be present i n order to activate the cambium.  Debudded Pinus s i l v e s t r i s were able to produce  auxin and activate the cambium i n the presence of needles 1971).  (Zimmerman,  Once the cambium i s activated i t can produce i t s own auxin  which w i l l stimulate the d i v i s i o n of cambial c e l l s .  Only  simultaneous  debudding and d e f o l i a t i o n of Pinus strobus prevented a c t i v a t i o n of the cambium (Zimmerman, 1971). The mechanistic theory developed i n the l a s t century by Schwendener and Metzger, i s based on the force of the wind against the crown as a basic factor f o r uneven d i s t r i b u t i o n i n the s i z e of annual rings at d i f f e r e n t heights.  By this theory the force of wind causes bending  stress within the tree, which i s uniformly d i s t r i b u t e d along the branchless part of the tree.  The amount of r a d i a l growth i s proportional  to the bending stress developed at various points of the bole. Growth d i s t r i b u t i o n shown i n Figure 2 can not be explained by any of the e x i s t i n g theories. The n u t r i t i o n a l theory which i s based on amount of foliage above some point within the tree cannot explain the change i n pattern of growth a f t e r thinning.  As shown i n Figure 2, a  tree at age 21, i n the f i r s t year a f t e r thinning, has v e r t i c a l growth  9.  d i s t r i b u t i o n s i m i l a r to the open grown tree.  The s i z e of the crown  and amount of the foliage i s the same as i n the previous year p r i o r to thinning when thickness of the annual layer at d i f f e r e n t heights i s t y p i c a l for stand grown trees. The conductive theory f a i l e d to explain the same phenomenon. The number of dead branches within any cross section i s the same as p r i o r to thinning, which means that conductivity i s not improved. The hormonal theory i s not able to give a s a t i s f a c t o r y explanation of growth d i s t r i b u t i o n within a l i v e crown.  Assuming  that movement of auxin through the branches has uniform speed, then time of beginning and length of time of cambial a c t i v i t y within the trunk i s a function of distance from the auxin producing bud to the trunk of the tree.  Consequently, the maximum size of the annual ring  must be at the top of the tree, which i s not the case. The most s i g n i f i c a n t change a f t e r thinning i s i n environmental conditions such as exposure of residual trees to the sunlight and d i f f e r e n t microclimate.  The residual trees w i l l have an open grown  tree v e r t i c a l growth d i s t r i b u t i o n u n t i l the crowns close again. None of the theories d e s c r i b e ^ f u l l y the differences that appear within trees i n d i s t r i b u t i o n of earlywood, latewood, and whole rings. The analyses which w i l l be described i n this thesis document decadal and annual elements of ring growth and demonstrate substantial differences in temperature patterns within one tree. however, to evaluate  f u l l y the e f f e c t s of temperature gradients and to  relate e x i s t i n g p a r t i a l explanations growth.  Much more work i s needed,  to a comprehensive theory of tree  10.  V  DESCRIPTION OF THE AREA  L o c a l i t y of the Investigation The study area l i e s at the southern part of the University of B r i t i s h Columbia Research Forest which i s located about 35 miles east of Vancouver and 4 miles north of Haney. The area was burned i n 1868 and reforested to mixed forest of Douglas-fir, western hemlock and western redcedar.  The Douglas-fir  trees were f i r s t established a f t e r the f i r e providing the shade for younger western hemlock and western redcedar ( G r i f f i t h , 1960). area i s within the Coastal Western Hemlock Zone, Wet  The  Sub-zone.  Vegetation at the sampling s i t e i s Moss type on G l a c i a l outwash, Pseudotsugeto-Tsugetum Heterophylla Eurynchietosum  Oregani  (Krajina,  1959). Estimated s i t e index of the area i s 150 (Douglas-fir) at age years.  100  At the present time average height of the stand i s 130 feet.  Climate of the area The climate of the area i s the same as f o r the rest of the lower Fraser Valley, maritime and influenced by the mountains on the northern part of the Forest.  Polar P a c i f i c a i r i s quite common, causing long  rainy periods i n f a l l and winter.  Due to the influence of the P a c i f i c  Ocean the winters are warm but very wet for the l a t i t u d e and the summers are usually hot and dry (Kendrew, 1955).  11.  Precipitation P r e c i p i t a t i o n on the Forest i s s i m i l a r t o the rest of the L i t t o r a l Climatic Zone of B r i t i s h Columbia.  Two periods can be  distinguished;  October to March i s moist with an average monthly p r e c i p i t a t i o n of 10.23  inches, and A p r i l to September with an average monthly p r e c i p i t a t i o n  of 4.27 inches.  to  1  J  Figure 3.  1  i  F  M  i  A  i  r*  M  J  i  J  i  A  i  S  i  O  r  N  i  D  -  Month  Average p r e c i p i t a t i o n for period 1958-1970 at Administration Building Weather Station.  12.  Dry periods occur i n June, July, and August with a 12 year average at the Administration Building area of 3.17, 2.40, and 3.76 inches of p r e c i p i t a t i o n respectively.  The maximum p r e c i p i t a t i o n  i s i n December and January with a 12 year average of 12.33 and 11.86 inches respectively.  Temperature  Temperature i s featured with very mild winters and cool summers. Average temperature f o r the winter period i s 39.33F and f o r the summer period 61.60F.  Average maximum temperature i s highest i n July, 73.23F,  and lowest i n January, 40.44F.  Average minimum temperature i s lowest  i n January, 31.12F and highest i n July 53.29F. (see F i g . 4). Within the period 1958-1970 the coldest month was January, 1970 with a mean minimum temperature of 19.8F and mean maximum temperature of 30.4F, recorded at the Administration Building Weather Station. In the same period the warmest month was August 1967 with a mean maximum temperature of 81.35F and a mean minimum temperature of 54.85F.  13.  cu cu t-l  OC CO  o  80-  H  J  Figure h.  1  1  M  F  M  A  M  f J  1 T  1  i  J  A  S  i  1  O  N  1 D  1  -  Month  Maximum, minimum, and average temperature f o r period 1958-1970 at Administration Building Weather Station.  Hours of bright sunshine  Within the Research Forest the number of hours of bright sunshine i s recorded only at the weather station on Spur 17, located 1.89 miles northeast of the Administration Building Weather Station. The number of rainy days at Spur 17 i s the same as at the Administration Building and the t o t a l r a i n f a l l exceeds that of the Administration Building by only 9%.  14.  Considering the proximity of Spur 17 to the Administration Building, and the s i m i l a r climatological parameters, i t i s probable that the number of hours of bright sunshine would be s i m i l a r . The minimum number of hours of bright sunshine i s i n December, being 30.47 hours and the maximum i s i n July, being 240.80 hours (Fig. 5).  CO  u a  o  tc  200  100  —i—  F  Figure 5.  —r  -  M  M  -i—  J  N  D - Month  Monthly average of hours of bright sunshine recorded at Spur 17.  15.  Climagraphs of the area  The two most important climate parameters, temperature and p r e c i p i t a t i o n , were used i n the construction of the climagraphs. Relationship between these two parameters determines the type of climate at any time of the year, gives the v a r i a b i l i t y between the years (Appendix No. 1.), and c l i m a t i c differences between different locations (Figs. 6 and 7). Four types of climate can explain the variations within the year and they are determined on the following relationship between temperature and p r e c i p i t a t i o n (Weiss, 1972). AR. - Arid Climate i s i n the period of the year when the monthly p r e c i p i t a t i o n (measured i n mm) i s less than double of the mean monthly temperature (measured i n °C). AR: P r e c i p i t a t i o n 2 x (monthly mean temperature) SA. - Semi-arid Climate i s within the period of the year when the monthly p r e c i p i t a t i o n (measured i n mm) i s less than three times the monthly mean temperature  (measured  i n °C). SA: P r e c i p i t a t i o n 3 x (monthly mean temperature) H. - Humid Climate i s within the period of the year when the p r e c i p i t a t i o n exceeds three times the mean monthly temperature, but i t i s less than 100 mm. H: 100 mm p r e c i p i t a t i o n 3 x (monthly mean temperature)  16.  Climagraph University of B r i t i s h Columbia Research Forest Administration Weather Station  Elevation 470 feet Yearly Average Temperature 49.23° F. (9.57° C.) Yearly Average P r e c i p i t a t i o n 87.08 inches (2211.83  Fig. 6.  Climagraph for period 1958-1970.  mm.)  Administration Weather Station.  17.  -Climagraph University of B r i t i s h Columbia Research Forest -Spur 17 Weather Station  H - humid PH - perhumid  400 i  300 -  o u fx 150 100  200 10080 •  90  60-  60  40  30  20-  1  - 40  2  3  4  5  6  7  8  9  10  Elevation 1285 feet Yearly Average Temperature 48.06°F. (8.92°C.) Yearly Average P r e c i p i t a t i o n 95.67 inches (2430.01  Fig. 7.  Climagraph f o r period 1958-1970.  11 12 Month  mm.)  Spur 17 Weather Station.  18.  PH. - Perhumid Climate i s within the period of the year when p r e c i p i t a t i o n (measured i n mm) exceeds double the value of the mean monthly temperature and i s over 100 mm. PH: P r e c i p i t a t i o n 100 mm and 2 x (monthly mean temperature)  From the climagraphs (Figs. 6 and 7) i t can be seen that within the summer the climate i s humid.  Due to difference i n the elevation,  the humid period i s longer at the Administration Building Weather Station (May-August) than at the Spur 17 Weather Station (JuneAugust) . Within the rest of the year the climate i s perhumid for both weather s t a t i o n s . A l l c l i m a t i c data indicate that the climate within the University of B r i t i s h Columbia Research Forest, as w e l l as on the sampling s i t e , i s l i t t o r a l with a l l the features which describe this type of climate.  19.  EQUIPMENT AND SAMPLING  Equipment The temperature measurements were recorded on charts for two years using a 24-channel M u l t i / r i t e r recorder.  The recording  temperature range was 0 to 300F with accurate chart reading of 5F. Overall accuracy was better than 0.25 percent of the f u l l scale, that i s , the maximum error due to the recorder was 0.75F. Temperatures were measured at four locations v e r t i c a l l y and three or f i v e locations h o r i z o n t a l l y with "Ceramo" metal sheeted, ceramic insulated thermocouple elements.  Depending upon the place  of application and i n s t a l l a t i o n requirements, four types of thermocouples were used: 1) For s o i l temperature measurements, protected thermocouples were used.  This type of thermocouple i s  designed f o r application where the measuring environment would be detrimental to an exposed thermocouple element, such as corrosive l i q u i d s and gasses.  In t h i s construction,  the magnesium oxide i n s u l a t i o n i s completely sealed from contamination and the measuring junction becomes an i n t e g r a l part of the t i p of the thermocouple.  Response  time f o r change i n temperature approaches that of an exposed thermocouple. 2) For temperature measurements i n sapwood and heartwood, spring-loaded thermocouples were used.  These are designed  20.  for application where the sensing t i p must maintain positive contact with the point of measurement.  In  t h i s type the thermocouple conductors are welded together to form a junction which i s insulated with magnesium oxide. The response time due to the insulators i s s l i g h t l y longer than that of the ceramic insulated thermocouples. 3) Shielded thermocouples were used f o r a i r temperature measurements.  These have an exposed loop junction  for a faster thermal response than the previous types described.  An open, "T"-shaped, s t a i n l e s s s t e e l  s h i e l d over the measuring junction reduces the effect of radiant heat transfer between the bark and the exposed thermocouple. 4) For temperature measurements on the bark surface and i n the inner bark, gasket thermocouples were used.  A  gasket thermocouple consists of insulated thermocouple wires, s i l v e r soldered to a c i r c u l a r metal gasket which then becomes the measuring junction.  The thermocouples  are supplied with a stainless s t e e l support between the gasket and the thermocouple wire to r e l i e v e stress at the measuring junction.  These thermocouple wires are  insulated with fiberglass (Anon. 1966).  Sampling Sampling was started at the end of July 1968 and was continued to the end of July 1970.  Within t h i s period, systematic sampling was  used and temperatures were recorded every weekend s t a r t i n g Friday afternoon and continuing u n t i l Monday morning.  In t h i s  way,  temperatures f o r two continuous 24-hour periods were recorded.  This  kind of sampling was used throughout that period with the exception of the l a s t week of August 1968, when temperatures were recorded f o r a f u l l week In order to gain more information and to make up for time lost i n the middle of August due to lack of recording charts. This research was designed to gain information on the temperature of the tree by placing various types of thermocouples i n d i f f e r e n t parts of the tree and i n d i f f e r e n t environments. The f i r s t set of thermocouples was placed at the root l e v e l , measuring the temperature of the s o i l , bark, and wood of the root. The root, 4 inches i n diameter, was 10 inches below the surface of the  soil.  The s o i l temperature was measured with a protected thermo-  couple probe 6 inches long and 0.25 inches i n diameter.  This thermo-  couple was waterproofed by an extension fiberglass wire and the p l a s t i c covering of the connector above the ground. For  temperature measurements under the bark of the root, a  standard gasket thermocouple was used.  This was placed tengentially  under the bark i n order to cut down conduction of heat toward or away from the point of measurement.  In the case of the r a d i a l bole, heat  flow takes place and the probe i s positioned to take heat away from  22.  or towards the point of measurement.  The magnitude of error caused  by r a d i a l i n s e r t i o n of the probe would increase with the diameter of the probe and decrease with the depth of the point of measurement (Herrington, 1969). A spring-loaded thermocouple without a lead was used f o r temperature measurements of the wood.  The probe was 0.125 inches  i n diameter with the minimum length 1.5 inches and the maximum length 2.125 inches.  In order to u t i l i z e the f u l l length of the thermocouple,  the probe was inserted i n t o the wood through a r a d i a l hole 0.125 inches i n diameter.  As the depth of the hole was 2 inches and the probe was  designed to give maximum protection from detrimental environmental conditions, the e r r o r due to r a d i a l i n s e r t i o n was n e g l i g i b l e . During sampling the p o s i t i o n of the thermocouple was maintained by a hexagonal nut adaptor. At 4.5 feet above the ground the temperature was measured at several locations. A i r temperature was measured with a shielded thermocouple, the measuring point being located 0.5 inches from the bark surface.  The  metal s h i e l d protected the exposed thermocouple wires from the radiation of the bark surface. For measurements on the bark surface and under the bark, gasket thermocouples were inserted i n the same way as i n the root. An increment borer sample was used to determine the depth of the sapwood.  For sapwood measurements a spring-loaded thermocouple was  used as described f o r the root measurements.  23.  Heartwood temperatures were measured with a spring-loaded thermocouple 0.125 inches i n diameter and a length range of 3.0003.625 inches. The same arrangement of thermocouples was used at 45 feet and 85 feet above the ground (Fig. 8). Data were collected i n f u l l only f o r the f i r s t two months because the complete set of thermocouples at the 85-foot l e v e l was l o s t during a 45 m.p.h. gale on the night of Sept. 17, 1968. to lack of funds the lost probes were not replaced.  Due  The sampling  done following t h i s date was only f o r the root, the 4.5 foot, and the  45 foot l e v e l s . Due to the excessive amount of data, i t was f e l t that analyses  covering a two month period would be most p r a c t i c a l . Block No. I represents the period of July 31 to August 25, 1968, the  warm period of the year; and Block No. II represents the period  from Dec. 1 to Dec. 29, 1968, the cold period of the year. Two thermocouples, the a i r temperature probe and the probe located within the bark at the 45-foot l e v e l were damaged p r i o r to the  Block II period, and a l l records originating from these locations  were discarded.  24.  F i g . 8.  R e l a t i v e p o s i t i o n s of sensors i n bark, sapwood, and heartwood.  25.  RESULTS  VERTICAL GROWTH DISTRIBUTION  In order to test t h e o r e t i c a l growth d i s t r i b u t i o n , and to f i t a tree on which research was done i n t o one of the known patterns, the amount of growth of earlywood,  latewood, and complete annual rings  was measured f o r a period of the l a s t f i f t y years.  Increments were  taken at 1.0, A.5, 15.0, 25.0, and every ten feet thereafter to the height of 85.0 feet.  In order to minimize growth v a r i a t i o n from year  to year, average width of annual rings for a period of ten years i s considered s u f f i c i e n t to provide a picture of tree development. Increments f o r the l a s t eleven years, for which accurate meteorological data are available, are shown separately i n order to i l l u s t r a t e v a r i a t i o n from year to year. From Figure 9, one can see that i n the early stage of development, 1921-1930, v e r t i c a l d i s t r i b u t i o n of the width of annual rings the growth pattern of a suppressed tree.  This p o s s i b i l i t y  resembles  was  confirmed with a e r i a l photographs of the area taken p r i o r to major development i n recent years.  West of this sampled tree, two probably  old growth Douglas-fir trees provided a s u f f i c i e n t amount of shade to cause such growth d i s t r i b u t i o n .  The most s t r i k i n g feature i n growth  d i s t r i b u t i o n i n t h i s stage of tree development i s the amount of e a r l y wood at the height of 85 feet.  Earlywood at that height exceeds l a t e -  wood by 3.8 times and can account f o r 79.3 percent of the t o t a l annual  26.  J2  60  "eu ,1921-30  1931-40  Earlywood Latewood T o t a l annual r i n g  1  J2 6C •H ,1941-50  0)  2"^  3 Width i n mms.  1951-60  PS  85 75 65 55 45 35 25  _ Earlywood . _ Latewood _ T o t a l annual  15 5t 0 1  F i g . 9.  2  3  Width i n mms.  Average widths and v e r t i c a l d i s t r i b u t i o n o f earlywood, latewood, and t o t a l annual r i n g s f o r p e r i o d 1921-30, 1931-40, 1941-50 and 1951-60. '.  ring  27.  Xi  en  •H eg cc  85  75 65 55 45 35 25 15  Earlywood Latewood T o t a l annual r i n g  5 0 F i g . 10.  ring.  Width  mm.  Average width and v e r t i c a l d i s t r i b u t i o n o f earlywood, and t o t a l annual r i n g s f o r p e r i o d 1961-70.  Minimum w i d t h o f the annual r i n g s o c c u r s at a h e i g h t  latewood,  of ten  f e e t above t h e ground, and i t i s exceeded by 4.4 times a t t h e maximum at 85 f e e t .  The p l a c e o f maximum w i d t h o f annual r i n g s a t t h a t  height  shows t h a t f o r D o u g l a s - f i r , maximum width i s not below t h e crown but somewhere i n the upper h a l f o f the crown.  T h i s i s confirmed by Smith  (1973) who found t h a t t h e maximum w i d t h o f earlywood  o c c u r s a t the  base o f t h e f u l l crown where n e e d l e s p e r s i s t t o the b o l e Maximum w i d t h o f latewood o c c u r s below t h e l i v e crown.  of the t r e e . Maximum width  o f annual r i n g i s c l o s e but below t h e p l a c e o f maximum w i d t h o f e a r l y wood.  The p e r i o d 1931-1940 i n d i c a t e s dominance o f the sampled  Douglas-fir  28.  tree within the stand.  Minimum width of the annual rings i s s t i l l at  the height of 15 feet.  The new features within the sample height are  two maximums of width of annual rings.  The f i r s t maximum i s close to  the ground and the second i s at 85 feet with strong indications that the true maximum i s above t h i s height.  From Figure 9 one can see  that the maximum width i n the upper part of the tree i s due to the width of earlywood which at 85 feet exceeds latewood by 3.2 times as compared with 1.7 at 15 f e e t . feet i s the same.  Width of latewood from 15 feet t o 85  In contrast, earlywood increases.  Width of l a t e -  wood at 85 feet exceeds that at 25 feet by 14 percent as compared with earlywood which exceeds by 118 percent.  This i s confirmed by Heger  (1965) and Smith e t al.(1966) who found that earlywood and latewood are d i s t r i b u t e d d i f f e r e n t l y and controlled by d i f f e r e n t factors. Growth d i s t r i b u t i o n of the width of annual rings i n the period 1941-1950 i s very close to the pattern described as a t y p i c a l opengrown tree pattern. to the ground.  The maximum width of the annual rings i s close  From the height of 15 to 65 feet, size of annual rings  i s uniform, except for small v a r i a t i o n s , and I t reaches i t s minimum at 85 f e e t .  This d i s t r i b u t i o n of width of annual rings i s conditioned by  latewood since earlywood has uniform width.  This pattern of growth  d i s t r i b u t i o n cannot be explained by any e x i s t i n g theories because growth conditions were s i m i l a r i n the previous period.  One possible  explanation which can be offered i s that Douglas-fir, i n certain stages of development, does not f i t a pattern of growth development  29.  by the stand.  In t h i s case a stand grown tree i s producing growth  t y p i c a l of an open grown tree. A s i m i l a r growth pattern i s seen i n the next period, 1951-1960 i n which the area was opened and the tree more exposed to an open grown environment. V e r t i c a l growth d i s t r i b u t i o n i n the period 1961-1970 again resembles that of a suppressed tree, despite the fact that further clearing of the environs opened the area west of the tree.  Due to  t h i s development one would expect growth d i s t r i b u t i o n to be s i m i l a r to that of an open grown tree, or a stand grown tree, assuming that the opening was not s u f f i c i e n t f o r a s i g n i f i c a n t change i n the growth pattern.  The minimum width of annual rings i s at ground l e v e l and  i t s maximum i s at 85 feet. Investigation of the 1961-1970 period on a year to year basis shows three groups of v e r t i c a l growth patterns.  In 1960 and 1961,  i t i s an open grown pattern, 1962 to 1968, a suppressed tree growth pattern, and 1968 to 1971 a pattern which does not resemble any of the basic patterns previously described  (Figs. 11-16).  In 1969 and  1970 the maximum width of annual rings as well as of earlywood and latewood moves from the crown area into the middle of the trunk well below the l i v e crown.  Assuming that the s i z e of the annual rings i s  the function of the length of the growing season, and the maximum length of the growing season i s within the crown due to earlypresence of auxin, t h i s i s quite unexpected.  Instead of an expected maximum  within the crown at i t s lower part, we have a minimum.  The maximum  30.  u co  •H CU 3C  1960  1961  85 75 65 55 45' 35 25  Earlywood Latewood Total annual ring  15' 5' 0  Width •-Fig. 11.  M 60 •H  1962  CU SB  mm.  Width of earlywood, latewood, and annual ring 1960 and 1961.  1963  85 75 65 55 45 35 25  Earlywood Latewood  15  Total annual ring  5 0  3 Fig. 12.  Width  mm.  Width of earlywood, latewood and annual ring 1962 and 1963,  31  u  •H CU  1964  1965  851 75 65 55 45 35 25  Earlywood Latewood Total annual ring  15 5 0 1 Fig. 13.  2  3  1  2  3  Width ram.  Width of earlywood, latewood, and annual ring 1964 and 1965,  Xi  60 •H CU  1966  1967  cn 85 75 65 55 45 35 25  Earlywood Latewood Total annual ring  15 5 0 1 F i g . 14.  2  3  1  2  3  Width  Width of earlywood, latewood, and annual ring 1966 and  mm. 1967.  32.  1969  Earlywood Latewood Total annual ring  3  1  2  3  Width  mm.  of earlywood, latewood, and annual ring 1968 and 1969.  of earlywood, latewood, and annual ring  1970.  33.  i s at a height of 45 feet and i t exceeds the minimum by 201 A possible explanation i s that i n 1967  a s t e e l tower was  percent.  erected  and  some branches of the sampled tree and one suppressed hemlock tree were removed i n order to accomodate the tower.  Furthermore, i n  1968  and 1969 measurements for several projects were made at a l l three levels and for these measurements a number of instruments were attached to the tree which further complicates  the problem.  The  climate of the area within the period can be ruled out because climagraphs for these years do not show any unusual features. climate was  humid and perhumid with the exception of August  when there was  The  1970  a short period of a r i d climate which i s not an unusual  feature i n summer. The lowest increment within the last eleven years was the year i n which the area west of the tree was explanation environment.  cleared.  in  1962,  A possible  for such an increment i s the shock due to change of The same change i s a possible reason for increased  production of earlywood and latewood i n the upper part of the trunk. In the period 1962-1967, v e r t i c a l d i s t r i b u t i o n of the widths of annual rings resembled that of a suppressed tree. lower part of the trunk was The increase was well  Growth i n the  s i m i l a r to that of the previous  period.  i n the upper part of the tree, i n the earlywood as  as i n the latewood, due to the change of l i g h t and  microclimate.  Ten year averages show d i f f e r e n t stages i n development of a Douglas-fir and a period of s t a b i l i z e d d i s t r i b u t i o n up to 1960. period 1960-1970 i s featured by s i g n i f i c a n t and frequent  The  changes which  34.  most l i k e l y can be attributed to the change i n the environment.  From  the graphs representing d i s t r i b u t i o n of earlywood, latewood, and complete annual rings, one can see that the significance of each part of the annual ring i s not the same. (1965) who  This i s i n agreement with Heger  found that the form of earlywood layers d i f f e r e d from that  of latewood.  Smith et a l . (1966) found that v a r i a t i o n i n thickness of  earlywood and t o t a l annual rings i s most s i g n i f i c a n t l y associated with the number of rings from the p i t h or r e c i p r o c a l of number of rings from the p i t h . Since the number of annual rings within the same tree i s a function of the height one can say that the most important influence on the width of annual rings, earlywood, and latewood i s the height at which the annual ring and i t s components are measured.  TEMPERATURE PROFILE OF THE TREE  Temperature measurements recorded during 1968 are divided i n t o two periods.  Period one consists of recordings made at the end of  July and during August and i t represents the temperature p r o f i l e of the tree within the growing season.  Temperature p r o f i l e of the  dormant period of the tree i s represented by the measurements made i n December 1968 and i t i s considered as period number two. The f i r s t period i s more i n t e r e s t i n g , not only because i t represents the productive period of the year, but also because the data are more complete.  Within the period due to daily  differences, one can d i s t i n g u i s h two sub-periods.  macroclimatic  The f i r s t  sub-period  35.  consists of recordings made on July 30, 31, and August 1 and 2, 1968. The common denominator f o r these four days i s that the maximum temperature recorded at the Administration Building weather s t a t i o n was in the eighties, minimum temperature i n the f i f t i e s , p r e c i p i t a t i o n n i l , and there was 10.5 - 13.3 hours of bright sunshine (Table 1 ) . Temperatures of the trees representing the second sub-period was recorded on August 22, 23, 24, and 25, 1968.  This sub-period represents  the rainy period of the summer. Meteorological s t a t i s t i c s recorded at the Administration Building are: maximum 58 to 68F, minimum 54 to 50F, p r e c i p i t a t i o n 0.03 to 0.74 inches and 0.0 to 4.5 hours of bright sunshine (Table 1 ) . Macroclimatic data recorded at the Administration Building i n December 1968 are given i n Table 2. The temperature data were analysed on an IBM 360, Model 67 computer using analysis of variance programme described by Dempster and Starkey, 1970.  Three way c l a s s i f i c a t i o n was used having the model:  Source of v a r i a t i o n  D.F:  V e r t i c a l temperature  (V-l)  Block  (B-l)  Horizontal temperature  (H-l)  Interaction vert, x block  (V-l)  (B- 1)  Interaction block x h o r i z o n t a l  (B-l)  (H- 1)  Interaction vert, x block x hor.  (V-l)  (B- 1) (H-l)  Experimental error  V H B (Q- 1)  Total  VHB Q  Table 1.  Macroclimatic s t a t i s t i c s July 30 to August 25, 1968 (Period 1) recorded at Building.  Day  Date  Maximum Temperature F  Minimum Temperature F  1  July 30  84  54  0  12.9  2  July 31  86  54  0  13.3  3  Aug. 1  84  58  0  13.1  4  Aug. 6  71  47  0  10.5  5  Aug. 22  60  53  .74  0  6  Aug. 23  61  54  .69  0  7  Aug. 24  68  51  .03  4.5  8  Aug. 25  58  53  .66  0  Precipitation Inches  Sunshine Hours  Administration  Remarks  Tenth day without r a i n  Table 2.  Macroclimatic s t a t i s t i c s Dec. 1 to Dec. 29, 1968 (Period 2) recorded at Administration Building.  Day  Date  Maximum Temperature °F  Minimum Temperature °F  Precipitation Inches  Sunshine Hours  1  Dec. 1  40  32  .27  0  2  Dec. 7  46  33  1.27  0  3  Dec. 14  54  40  .09  0  4  Dec. 15  46  42  .46  0  5  Dec. 21  34  25  .40  .1  6  Dec. 22  41  29  1.01  7  Dec. 28  6  1  0.0  6.5  8  Dec. 29  9  -4  0.0  6.8  0  Remarks  4 inches of snow  38,  The significance of differences between various points of measurements i s given i n Table 3.  In t h i s table, points of measurement  are within the trunk of the tree.  Table 4 represents the results for  the same period but taking into account root temperature as a fourth l e v e l of sampling. F values f o r the winter period of the year are l i s t e d i n Table 5 showing the differences between root, 4.5, and 45.0 feet above the ground. A graphical presentation of actual measurements of one hot summer day i s shown i n Figures 17, 18, and 19.  Figure 17 shows the cooling  and heating process at breast height which i s quite slow and reaches maximum temperature at 5 p.m.  The graph showing temperatures at 85.0  feet i s another extreme, Figure 19. finished, from 6 to 10 a.m.  After the cooling process i s  temperature of the bark i s raised by 17.2F  as compared to the height of 4.5 feet above the ground.  From the same  figures, one can see that the times of occurrence of maximum and minimum temperatures at different points of measurement within the same v e r t i c a l l e v e l are d i f f e r e n t .  With the increased depth i n the wood,  maximum and minimum temperatures occur l a t e r as compared to the place of energy exchange.  Regression l i n e s which can describe expected time  of maximum temperature are different f o r d i f f e r e n t heights and dependent on diameter at the measuring point.  Regression equations f o r period one  which give a time of occurrence of maximum temperature are: Y = 15.67 + 1.06 X  at breast height (1)  Y = 14.56 + 1.20 X  at 45 feet  (2)  Table 3.  F values for measurements above the ground, Period 1.  V e r t i c a l l e v e l s : 4.5, 45.0, and 85.0 feet. Day  Vertical  Block  Horizontal  V x B  V x H  B x H  V x B x H  1  62.18**  276.57**  1.42  2.38  0.72  18.91**  0.75  2  63.46**  163.75**  0.40  1.00  0.84  14.02**  0.51  3  66.16**  159.43**  1.01  1.45  0.98  15.53**  0.67  4  22.46**  198.18**  1.02  2.60  0.13  16.38**  0.74  5  57.94**  212.12**  6.26**  2.37  0.40  13.39**  0.88  6  88.72**  185.22**  0.10  5.31**  0.18  10.22**  0.88  7  57.62**  184.77**  0.26  6.76**  0.41  20.31**  1.32  8  158.87**  41.36**  5.42**  4.14**  13.66**  1.30  63.57**  ** Highly s i g n i f i c a n t - l e v e l of significance  0.5%  Remarks  Horizontal levels 1,2,4,5  Table 4.  F values for a l l measurements, Period 1.  V e r t i c a l l e v e l s : root, 4.5, 45.0, and 85.0 feet.  Day  Vertical  Block  Horizontal  V x B  V x H  B x H  V x B x H  1  125.36**  215.87**  3.88  10.98**  0.50  13.89**  1.24  2  128.39**  131.44**  2.05  6.79**  0.60  10.91**  0.85  3  120.76**  121.64**  0.53  6.24**  1.64  10.02**  1.30  4  23.08**  161.05**  0.70  7.79**  0.17  11.77**  1.02  5  23.34**  158.25**  0.68  4.77**  0.04  0.18  0.11  6  40.92**  123.04**  0.11  5.49**  0.11  0.26  0.08  7  22.91**  146.96**  0.01  7.65**  0.27  0.34  0.14  8  36.39**  49.35**  1.29  3.97**  0.40  0.16  0.13  ** Highly s i g n i f i c a n t - l e v e l of significance  0.5%  Remarks  Horizontal levels 1 and 2  Table 5.  F values f o r Period 2.  V e r t i c a l l e v e l s : root, 4.5, and 45 feet, Day  Vertical  Block  Horizontal  VxB  VxH  BxH  V x B x H  Remarks  1 36.53**  40.09**  14.46**  346.51**  25.43**  120.69**  7  7808.21**  92.80**  8  9720.06**  68.42**  2  4.62  14.20**  8.94**  1.94  Mild  10.13**  99.78**  30.27**  9.74**  Cold  639.14**  16.48**  69.67**  37.73**  10.85**  133.70**  29.62**  136.51**  4.18  3 4 5. 6  ** Highly s i g n i f i c a n t - l e v e l of significance  0.5%  3.36  Very cold Very cold  Y = 15.80 + 0.79 X  at 85 feet (3)  In the equations X value f o r bark surface i s 1 and range of data i s from bark surface to 3.5 inches into the wood. Figures 21 to 30 represent graphical presentations of actual temperature measurements at the same depth but at the d i f f e r e n t levels.  From the Figures 21 to 25 one can see that under clear sky  conditions the temperatures are higher with the height of sampling point at any time of the day or night.  In cloudy conditions the mean  temperatures are higher with the height of sampling point but they overlap each other due to small differences between the temperatures, Figures 26 to 30.  43. V  DISCUSSION  As expected, results of the analyses of variance show highly s i g n i f i c a n t differences between different v e r t i c a l l e v e l s .  Duncan's  Multiple Range Test shows that any of the two means d i f f e r s i g n i f i c a n t l y and the highest temperatures are at 85 feet above the ground.  This high temperature at the upper part of the trees may  be one of the s i g n i f i c a n t influences on the width of annual rings. The difference between the blocks, where each block a period of s i x hours, i s also highly s i g n i f i c a n t .  represents  This difference  i s not only due to d i f f e r e n t means but also because of d i f f e r e n t temperature trends i n each of the blocks.  For the f i r s t s i x hours  the temperature trend i s downward due to the cooling process. the next two periods the trend i s upward due to the heating  For  process,  and t h i s i s succeeded by the cooling process and downward trend, Figures 17 to 20.  The temperature trend within each block depends on  the depth of the point of measurement and with increased depth and diameter at the point of measurement a s h i f t to the right occurs, as i n the case of heartwood at 4.5 feet, Figure 17.  The expected s h i f t  to the right due to depth and diameter i s given by regression equations 1, 2, and 3. Differences between temperatures at the horizontal l e v e l s are not s i g n i f i c a n t i n the summer period due to the very small differences between the means, Tables 3 and 4. Table 3 shows highly s i g n i f i c a n t i n t e r a c t i o n between the blocks  44.  Time of the day.  ^Location of thermocouple  Maximum Temperature  Minimum Temperature  Range  Air Bark surface Inside of bark Sapwood Heartwood  81.0 79.5 76.7 73.5 71.0  61.0 62.0 62.5 65.0 66.5  20.0 17.5 14.2 8.5 4.5  Figure 17.  —  Stem temperature changes on August 1, 1968 at 4.5 f t . above the ground.  45.  F.  90'-  60  12  18  24  Time of the day.  Location of thermocouple Air Bark surface Inside of bark Sapwood Heartwood Figure 18.  Maximum Temperature 85.3 82.0 82.0 79.8 78.0  Minimum Temperature 62.0 62.7 62.7 66.5 70.3  Range 23.3 19.3 19.3 13.3 7.7  Stem temperature changes on August 1, 1968 at 45.0 f t . above the ground.  46.  Location of thermocouple Air Bark Surface Inside of bark Sapwood Heartwood Figure 19.  Maximum Temperature  Minimum Temperature  84.7 86.7 84.5 83.5 83.0  62.5 62.5 64.0 66.7 69.0  Range 22.2 24.2 20.5 16.8 14.0  Stem temperature changes on August 1, 1968 at 85.0 f t . above the ground.  47.  Location of thermocouple Air Bark surface Inside of bark Sapwood Heartwood Figure 20.  Maximum Temperature  Minimum Temperature  58.2 58.1 58.0 57.5 57.3  54.8 54.9 55.0 55.5 55.9  Range 3.4 3.2 3.0 2.0 1.4  Stem temperature changes on August 22, 1968 at 4.5 f t . above the ground.  48.  and horizontal temperatures.  The significance of t h i s interaction  can be attributed to the s h i f t of sapwood and heartwood temperature waves to the r i g h t , Figure 17. contributing  The other factor which may be  to the significance of this Interaction i s the difference  i n the speed of heating, depending upon the depth of wood.  This i s  causing a difference i n temperature slopes within the blocks. In Table 4 horizontal temperatures are only for the environment in which measurements are taken, the barkwood and the sapwood. It shows s i g n i f i c a n t interaction between blocks and horizontal temperatures only on sunny days.  In cloudy conditions interaction i s not s i g n i f i c a n t  because of the minimal s h i f t and the minimal d a i l y temperature change within any point of measurement.  At the same time interaction between  v e r t i c a l gradiants and blocks i s s i g n i f i c a n t which was not the case i n Table 3.  I t i s obvious that t h i s significance of interaction i s due  to root temperatures which are more stable than the temperatures of the stem.  In some of the blocks temperature changes of the root within the  block are i n s i g n i f i c a n t as compared with temperature changes i n the stem or i n the a i r , Figures 21, 22, 24, 26, 27, and 29. The high significance f o r blocks and significance of differences between v e r t i c a l levels i n Table 4 can be explained i n the same way as i n Table 3. Table 5 shows results of analyses of variance f o r data collected i n December 1968.  On the majority of these days there i s a high  significance of each of the sources of v a r i a t i o n .  These significances  are due to measurements i n the s o i l and open a i r environment and the  49.  Soil  12  6  18 24 Time of the day.  Figure 21. Temperature of the environment on August 1, 1968.  6~~'  ' ' '  12  ~  18 ' ' ""^ "~24 Time of the day.  Figure 22. Temperature of the bark surface at different vertical levels on August 1, 1968.  50.  F. 80  4.5 f t . 45.0 ft 85.0 ft  70  60  Figure 23.  1-2  18 24 Time of the day.  Temperature inside of the bark at different vertical levels on August 1, 1968.  F. 80  70  60  Figure 24.  12  18 24 Time of the day.  Temperature of the sapwood at different vertical levels on August 1, 1968.  51.  4.5 f t . 45.0 f t . 85.0 f t .  Time of the day.  Figure 25.  Temperature of the heartwood at different vertical levels on August 1, 1968.  52.  541  .  . . .  6  1 2 "  18  ' 2'4  Time of the day.  Figure 26.  Temperature of the environment on August 22, 1968.  54<  6  • 1.2  18  24  Time of the day.  Figure 27.  Temperature of the bark surface at different v e r t i c a l levels on August 22, 1968.  53.  4.5 f t .  6  ' '  '  '  12  '  '  '  18  ' '  '  "~24~  Time of the day.  Figure 28.  Temperature inside of the bark at different v e r t i c a l levels on August 22, 1968.  Root 4.5 f t . 45.0 f t . 85.0 f t .  Time of the day.  Figure 29.  Temperature of the sapwood at different v e r t i c a l levels on August 22, 1968.  54.  Figure 30.  Temperature of the heartwood at different v e r t i c a l levels on August 22, 1968.  55.  differences between the two.  At the same time the test was extremely  sensitive and minimal differences were picked up due to the large degree of freedom f o r experimental error.  Temperature  differences  within this period do not have the same importance to the annual ring formation as temperatures within the growing season.  I t should be  noted that root temperature i s higher than stem temperature.  This  temperature difference could explain the early beginning of root cambial a c t i v i t y . Temperature differences within the growing season are more important and can be offered as part of the explanation f o r the d i f f e r e n t s i z e of annual rings at d i f f e r e n t heights. Temperature, as w e l l as l i g h t , i s one of the important environmental factors i n tree growth and development.  Temperature  influences  p h y s i o l o g i c a l a c t i v i t i e s of the plant through i t s e f f e c t on the rate of metabolism (Zimmerman, 1971).  Plant requirements i n regard to  temperature are expressed i n terms of optimum temperature and upper and lower temperature l i m i t s .  Plant exposure to temperatures above or below  optimum temperature w i l l produce lengthening of time of development plant growth (Lowry, 1970).  and  Cytoplasmic streaming i n the cambium i s an  important indicator of cambial a c t i v i t y and can be affected by the temperature and the time of year. no streaming.  At the temperature of -1°C there i s  Between 5°C and 34°C there i s a l i n e a r increase i n rate  of streaming followed by a sharp drop between 34°C and 42°C.  Exposure  of the cambial c e l l s of Pinus s i l v e s t r i s to a temperature of 40-42°C for two or three minutes was l e t h a l (Thimann eit a l . , 1957).  The optimum  56.  temperature and l i m i t s are not w e l l defined because of d i f f e r e n t species and the change of temperature requirements for the same species through the development stages. The beginning of cambial a c t i v i t i e s i s not only dependent on a i r temperature but even more on s o i l temperature.  In independently  controlled s o i l and a i r environment, at the constant s o i l temperature of 40F and a i r temperature of 80F during the day and 60F during the night, the growth of the Douglas-fir seedlings was n i l .  The f i r s t  sign of new growth was noticed when the s o i l temperature was above 40F (Hocking, 1972).  raised  Significance of temperature on root growth  was demonstrated i n controlled environmental conditions, where the root medium was maintained at three temperature l e v e l s .  The root temperature  was controlled at 1.7, 4.4, and 7.2°C, and the dormant shoots were maintained at 15°c at day time and 10°C at night. the  Cambial a c t i v i t y of  shoots was not recorded for any combination of temperatures, but  s i g n i f i c a n t root growth was recorded f o r Taxus and Forsythia plants maintained at 4.4°C and 7.2°C (Meyer, 1967).  The diameter growth of  roots commences before the growth of any other part of the plant because the minimum temperature requirement for root growth i s lower than that of the stem or the branches (Amilon, 1910). Before any diameter growth can take place the cambium must reach a temperature which i s above a minimum required f o r the s t a r t of cambial activity.  Since the temperature of the trees i s conditioned by the  environment, thickness of bark, which has a very low heat conductivity, i s one of the s i g n i f i c a n t factors on the time of i n i t i a l diameter growth.  57.  The investigation shows that thin-barked species had started diameter growth e a r l i e r than thick-barked species (Amilon, 1910).  Favourable  temperature conditions i n the beginning of the growing season can cause a faster diameter growth due to the number of c e l l layers which i s higher than i n a cold year. wood formation (Zumer, 1969).  In cold periods there i s l i t t l e or no The production of lammas shoots and  f a l s e annual rings was influenced more by environmental than genetic factors (Walters, 1961).  Smith (1973) found that climate influenced  growth more than any other factor including f e r t i l i z a t i o n .  Sudden  and severe temperature changes such as a frost reduced the growth. High spring and summer temperatures promoted the growth of earlywood but c u r t a i l e d the growth of latewood. Temperature i s not only related to the rate of cambial d i v i s i o n , but also to the length of tracheids. to 25°C  Increased night temperature up  caused an increased diameter growth and tracheid length as  compared to control plots i n one-year-old Sequoia sempervirens and Douglas-fir seedlings.  A temperature bridge which maintained a  temperature 5°C above the ambient showed the e f f e c t of temperature on the tracheid length of Sitka spruce seedlings.  After a period"of  s i x weeks, tracheid lengths were measured within the bridge and below it.  It was found that c e l l s within the bridge were s i g n i f i c a n t l y  longer than below the bridge where the temperature was lower (Brown, 1970). A l l these examples indicate the significance of temperature on  58.  tree growth.  I t also indicates that temperature may be one of the  factors i n the bole formation.  59.  CONCLUSION  Tree ring analysis of the sampled dominant Douglas-fir tree shows that Douglas-fir may  f i t t h e o r e t i c a l diameter growth  d i s t r i b u t i o n only i n the early stages of development.  In the  t h r i f t y stage, growth below the crown shows small v a r i a t i o n s . This i s not the case with other species.  It also shows the  extreme s e n s i t i v i t y of Douglas-fir growth to environmental changes and as a reaction a s h i f t of maximum width of annual rings below the crown.  In early stages of development,  the maximum width of  the annual rings i s i n the middle or i n the upper part of the crown which may be attributed to temperature requirements and actual temperatures within the crown. Temperature measurements indicate that the highest are expected to be i n the upper part of the tree.  temperatures  Direct temperature  c o r r e l a t i o n with the amount of growth of annual rings i s d i f f i c u l t to prove.  By comparison of actual data f o r growth and temperature, one  can conclude that there i s a very good chance that temperature  may  be one of the s i g n i f i c a n t variables on amount of growth i n various parts of the tree.  Perhaps a s i m i l a r experiment should be repeated  with temperature measurements taken on several dominant, codominant, and suppressed trees.  At the same time one could maintain the  temperature of one part of the trunk at a lower l i m i t of cambial a c t i v i t y and compare the growth within that part with the rest of the  60.  tree exposed to the normal environment. Recognizing the fact that temperature requirements are different for various species and even f o r the same species, and that they vary with the stage of development, one can say that cambial a c t i v i t y w i l l not s t a r t u n t i l the temperature of the cambium reaches the lower temperature l i m i t .  This lower temperature l i m i t w i l l be reached at  d i f f e r e n t times i n different parts of the tree.  I t w i l l be reached  f i r s t within the crown and l a s t within the lower part of the tree. Because of this difference, length of growing season i s different i n various parts of the tree. The other variable i s optimum growth temperature, i t s length, and the time of the year when i t occurs.  I f optimum temperature i s  reached early i n the year and stays f o r some length of time, i t w i l l cause a larger annual ring within the part affected.  I f that  temperature i s reached during the dry season, the temperature advantage i s l o s t due to the unsatisfactory conditions of other variables on which the growth  depends.  In order to determine the significance of temperature as a factor influencing d i s t r i b u t i o n of r a d i a l growth i n tree boles, further research i s needed.  61.  BIBLIOGRAPHY  Amilon, J.A. 1910. On the time of commencement of diameter growth of coniferous trees. Translation from Swedish. Can. Dept. of For. 1968. 27 pp. Anon. 1966. Thermo e l e c t r i c miniature thermocouples. E l e c t r i c (Canada) Ltd. 12 pp. Brown, C.L. 1970. Science 3:1. pp.  Thermo  Physiology of wood formation i n c o n i f e r s . 8-22.  Wood  Dempster, J.R.H., and G.E. Storkey. 1970. Analysis of variance. University of B r i t i s h Columbia Computing Centre, Vancouver 8, B.C. 32 pp. Farrar, J.L. 1961. the annual rings. Geiger, R. 1950. 412 pp.  Longitudinal variations i n the thickness For. Chron. 37: 323-331. The climate near the ground.  of  Harvard Univ. Press.  G r i f f i t h , B.G. 1960. Growth of Douglas-fir at the University of B r i t i s h Columbia Research Forest as related to climate and s o i l . For. Bui. No. 2. Fac. of Forestry, University of B r i t i s h Columbia, Vancouver 8, B.C. 58 pp. Heckert, L. 1959. of Forestry 1963.  Climatic conditions 27 pp.  i n a deciduous f o r e s t .  Dept.  Heger, L. 1965. Morphogenesis of stems of Douglas-fir. Ph.D. thesis. Fac. of Forestry, University of B r i t i s h Columbia, Vancouver 8, B.C. 176 pp. Herrington, L.P. 1964. A t h e o r e t i c a l and experimental investigation of the temperature f i e l d i n tree stems. Ph.D. thesis. Yale University. 185 pp. . 1969. On temperature and heat flow i n tree stems. Bui. No.73. Yale University. Hocking, D. 1972. Proceedings of a workshop on container Can. For. Ser. 48-71.  planting.  Kendrew, W.G. and D. Ker. 1955. The climate of B r i t i s h Columbia and the Yukon T e r r i t o r i e s . Dept. of Transport, Meteorological Div. pp. 1-222.  62.  Kozlowski, T.T. 1971. Growth and development of trees. V o l . 2. Academic Press. New York. pp. 437. Krajina, V.J. 1959. Bioclimatic zones i n B r i t i s h Columbia. Botanical Series No. 1. University of B r i t i s h Columbia, Vancouver 8, B.C. 22 pp. Lowry, W.P. pp.  1970.  Weather and l i f e .  Academic Press. New York. 291  Meyer, M.M. J r . , and H.B. Tukey. 1967. Influence of root temperature and nutrient applications on root growth and mineral nutrient content of Taxus and Forsythia plants during the dormant season. American Society f o r H o r t i c u l t u r a l Science. 90:440-446. Smith, J.H.G. 1973. Influence of nitrogen f e r t i l i z a t i o n on widths and s p e c i f i c gravity of earlywood and latewood and bh growth i n volume and weight of young Douglas-fir trees. Progress Report. Fac. of Forestry, University of B r i t i s h Columbia, Vancouver 8, B.C. , L. Heger, and J . Hejjas.1966. Patterns i n growth of earlywood, latewood, and percentage of latewood determined by complete analysis of eighteen Douglas-fir trees. Can. Jour, of Botany, V o l . 44. pp. 453-466. Thimann, K.V. 1957. Press. New York.  The physiology of forest trees.  The Ronald  Walters, J . 1960. V e r t i c a l temperature gradients i n two forest associations of the coastal western hemlock zone near Haney, B.C. Progress Report. University of B r i t i s h Columbia, Vancouver 8, B.C. 7 PP, and J . Soos. 1961. Some observations on the relationship of lammas shoots to the form and growth of Douglas-fir seedlings. Res. Pap. No. 4. Fac. of Forestry, University of B r i t i s h Columbia, Vancouver 8, B.C. . 1962. The v e r t i c a l and horizontal organization of growth i n some conifers of B r i t i s h Columbia. Res. Pap. No. 51. Fac. of Forestry, University of B r i t i s h Columbia, Vancouver 8, B.C. Weiss, J.K. 1972. Forest ecosystem of tree farm licence No. 27 Nitinat Lake, B.C. B.C.R.F. thesis, not published. 45 pp. Zimmerman, M.H. and C L . Brown. 1971. Springer Verlag. New York pp. 67-87.  Tree structure and function.  63.  Zumer, M. 1966. Annual ring formation on Norway spruce i n mountain forest. Norwegian Forest Res. Inst. Vollebekk, Norway.  64.  APPENDIX  Climagraphs of the area for period 1960-1970.  65.  Climagraph 1960 University of B r i t i s h Columbia Research Forest Administration Weather Station  Elevation 470 feet Monthly Average Temperature 9.40 C. Monthly Average P r e c i p i t a t i o n 164.80 mm.  66.  Climagraph 1961 University of B r i t i s h Columbia Research Forest Administration Weather Station  500 400  1 2 3 4  5  6  Elevation 470 feet Monthly Average Temperature 9.60 C Monthly Average P r e c i p i t a t i o n 208.89  7  mm.  8  9  10  11  12  Month  67.  Climagraph 1962 University of B r i t i s h Columbia Research Forest Administration Weather Station  Elevation 470 feet Monthly Average Temperature 9.37°C Monthly Average P r e c i p i t a t i o n 186.79  mm.  68.  Climagraph 1963 University of B r i t i s h Columbia Research Forest Administration Weather Station  1  2  3  A  5  6  Elevation 470 feet. Monthly Average Temperature 9.75°C Monthly Average P r e c i p i t a t i o n 174.41 mm.  7  8  9  10 11  12  1 0  Month  69.  Elevation 470 feet Monthly Average Temperature 8.70 C Monthly Average P r e c i p i t a t i o n 201.37 mm.  70.  Climagraph 1965 University of B r i t i s h Columbia Research Forest Administration Weather Station  i . 1 2  . 3  • 4  . 5  • 6  . . 7 8  Elevation 470 feet Monthly Average Temperature 9.46 C Monthly Average P r e c i p i t a t i o n 161.38 mm.  • 9  . 10  . 1 0 11 12  Month  71.  Climagraph 1966 University of B r i t i s h Columbia Research Forest Administration Weather Station  1  2  3 4  5  6  Elevation 470 feet Monthly Average Temperature 9.45 C. Monthly Average P r e c i p i t a t i o n 199.91 mm.  7  8 9  10 11 12  Month  72.  Climagraph 1967 University of B r i t i s h Columbia Research Forest Administration Weather Station  Elevation 470 feet Monthly Average Temperature 10.26°C. Monthly Average P r e c i p i t a t i o n 196.35  mm.  73.  Climagraph 1968 University of B r i t i s h Columbia Research Forest Administration Weather Station  1  2 3  4  5  6  7 8  Elevation 470 feet. Monthly Average Temperature 9.49°C. Monthly Average P r e c i p i t a t i o n 216.17 mm.  9  10  11 12  Month  74.  Climagraph 1969 University of B r i t i s h Columbia Research Forest Administration Weather Station  Elevation 470 feet Monthly Average Temperature 9.22 C. Monthly Average P r e c i p i t a t i o n 154.70  mm.  75.  Climagraph 1970 University of B r i t i s h Columbia Research Forest Administration Weather Station  I  i  1  2  i  3  4  5  6  Elevation 470 feet Monthly Average Temperature 9.25°C Monthly Average P r e c i p i t a t i o n 162.62 mm  7  —,  ,  8  9  .  .  10 11  J  12  0 Month  

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