Permeability to creosote of sapwood, included sapwood, and normal heartwood of a mountain-type Douglas fir stem was correlated with specific gravity, growth rate, percent summerwood, tracheid length, number of longitudinal resin ducts, alcohol-benzene, acetone and ether-soluble extractive contents of the corresponding zones. The effect of pressure and temperature on creosote retention was tested on creosote retention in true sapwood, included sapwood (abnormal heartwood), and normal heartwood. Test specimens were extracted in different solvents and ease of penetration tested by creosote impregnation. Among the factors investigated in the present study, specific gravity, tracheid length, growth rate, and number of longitudinal resin ducts did not have a measurable influence on creosote retention. Percent summerwood did not vary significantly at the five positions tested. Pressure had the greatest effect on creosote retention at 212°F. for heartwood, less for included sapwood and least for sapwood. The influence of temperature on creosote retention in Douglas fir heartwood was greater at 100 psi pressure than at atmospheric pressure. The effect of alcohol-benzene and acetone-soluble extractives on wood permeability was not proven statistically significant. A visual hyperbolic relationship was obtained between ether-soluble extractives and wood permeability. The higher the extractive content, the greater the retention. Pre-treatment of samples with different solvents, in order to remove some of the extractives, improved the permeability of heartwood and included sapwood significantly but caused only a slight improvement in sapwood. / Forestry, Faculty of / Graduate

A knowledge of the form of tree stems, and of the manner in which such stems vary in taper, are of importance to the forester in the determination of volume and in the construction of volume tables. At present there are two theories relating to stem-form, namely those of Metzger and Gray, and several formulae for constructing stem-profiles. The theory of Metzger is the oldest and most well known. He claimed that the form of the forest tree stem is not fortuitous but depends on certain forces acting on it, of which wind is the most important. Metzger described the tree stem as a "beam of uniform resistance" which, according to the laws of statics, is a cubic paraboloid. More recently Gray has disagreed with this theory, arguing that because the base of the beam is not fixed in a solid stratum, as Metzger supposed, the cubic paraboloid would in fact be too strong and therefore uneconomical. He claimed that the most economical stem form is that of a quadratic paraboloid. The quadratic paraboloid was tested for a number of trees from the University Research Forest and in each case was found to be closely correlated with the actual stem profile, except at the butt due to butt swell, and at the top where the stem resembled a cone. The cubic paraboloid was found to give a good fit in the lower part of the stem but under-estimated the diameter in the upper part of the stem. An American investigator, C. E. Behre, described the stem profile as a hyperbola. Although no theory has been published as to why this should be the case, the formula derived by Behre has gained wide acceptance in North America and many other parts of the world. The formula, in theory at least, gives a perfect fit to a cylinder or a cone and also good fits to the major parts of quadratic and cubic paraboloids and intermediate forms of stem profile. When used in this study, Behre's formula was found to give a slightly better fit than the quadratic paraboloid. The formula describing the stem profile of a quadratic paraboloid, called the "taper-line" by Gray, is of the form D² = a - bH, where D is the diameter of the stem at a height H, "a" is the regression constant, and "b" is the regression coefficient. The regression coefficient is an index of the slope of the taper-line, and therefore of taper, and can be used to trace the pattern of taper variation with various factors which are thought to be related to taper. By using multiple regression techniques it is possible to reduce these factors to one or two. In one such test on ten Douglas fir trees from a mixed fir, hemlock, and cedar stand, average age about 65 years, it was found that age and site index were not important but that diameter at breast height, D₄.₅²/Ht, and total height, Ht, were. The final regression obtained was b = 0.0242 + 0.998840 D₄.₅²/Ht. A similar regression was obtained for "a", the regression constant, and tables of values of "a" and of "b" were constructed. From these tables it is possible to derive the taper-line for any tree of known d.b.h. and height. By this means it is possible to calculate the volume of standing trees. The main conclusions reached in this thesis are that the form of forest tree stems is complex and cannot be ascribed readily to either of the known theories; the quadratic paraboloid gives a sufficiently good fit over the main part of the stem (between about 15 and 80 per cent of the total height) that it can be used as a basis for studying taper variation; and finally, that the amount of taper present in a stem varies directly as the square of diameter at breast height and inversely as the total height. The amount of taper appears to increase throughout the life of the tree as long as the tree remains in the dominant crown class. As soon as the tree passes into the codominant class the rate of increase in taper falls off and when the tree passes into the intermediate and suppressed classes the amount of taper decreases with increasing age. The form of a tree grown in the open, that is apparently free from competition from surrounding trees, resembles a cone, or a neiloid in some cases, and not the quadratic paraboloid of a close-grown or forest tree. / Forestry, Faculty of / Graduate

The purpose and history of glue bond testing have been reviewed. Certain deficiencies of standard test methods have been elaborated, and the need for a more accurate test procedure stated. The objective of this particular research was to develop a test that would meet such a need. Experimentation was limited to Douglas fir veneers bonded with hot-press phenolic resin adhesives. The following requirements of an ideal method of estimating glue bond quality were used as a guide in selecting new designs. The foremost requirement is reproducibility of test results. Other essential features include a universally acceptable unit of measurement and a test specimen which is simple and economical to prepare. Other desirable features are that a maximum number of specimens be obtainable from a given sample, and that the method be adaptable to both research and production testing. The Glueline-Cleavage Test developed through this research meets all of the above requirements. The principle is to measure the force required to split or cleave a one inch square plywood specimen along the glue line by means of a "knife" or wedge. The action is similar to the splitting of any wood with a wedge except that the knife is particularly positioned along the glue line. Specimens for this purpose may be either cross-banded or laminated. If the data are to be directly comparable every detail of the specimen, manufacture, testing machine, and test procedure must be standardized. This requirement is common to all methods of test. For quality control purposes test specimens would be out from the plywood at an angle of forty-five degrees to the grain. Every glue line of the specimen may be tested. Special two-ply specimens have been designed for research purposes where accuracy is of the utmost importance. In this type, the material is cut so that the cells intersect the veneer surface at an angle of ten degrees. This small angle, plus the relative weakness of wood in tension perpendicular to the grain, tends to concentrate the stress in the glue line. This insures a glue line failure when the knife is applied in the correct direction. If the knife is not applied in the correct direction the specimen tends to split along the grain of the wood away from the glue line rather than toward it as intended. These research specimens are prepared from two edge-grain veneers glued with the springwood-summerwood bands crossed. Any cross-banding angle up to ninety degrees (common for commercial plywood) may be used. The strengths of matched phenolic-bonded Douglas fir glue lines were compared by five methods, four being mechanical and one relying on wood failure. The mechanical methods were the Block Shear, Glueline-Cleavage, Tension Normal to the Glue Line, and Tension Shear Tests. The Per Cent Wood Failure Method employed wood failure readings from the Tension Shear specimens as estimates of bond quality. The Glueline-Cleavage and Tension Shear Methods included several test specimen designs. The above-mentioned comparisons yielded the following information. (1) mechanical methods proved more accurate than those based upon wood failure estimations, (2) for quality-control purposes the Glueline-Cleavage Test was shown to be equal or superior to the other mechanical methods, and (3) the Glueline-Cleavage Test, when used with specimens designed for research purposes, proved of superior accuracy to all others tested. Additional advantages of the Glueline-Cleavage Method include: (1) the simplest possible test specimen shape and therefore simple and inexpensive manufacture, (2) a maximum yield of specimens from a given plywood sample (a valuable feature with experimental designs requiring large numbers of matched specimens), (3) a lower time requirement per test, (4) much less expensive machinery is required to perform the test, and (5) the exposure of every glue line for inspection purposes when research-type specimens are used. Although the Glueline-Cleavage Test is believed to be the most accurate method yet developed, imperfections remain and several further methods have been proposed for increasing its accuracy. / Forestry, Faculty of / Graduate

This thesis investigated the temperature and growth profile of one Douglas-fir tree. A series of thermocouples located at different heights and depths was connected to one multi-channeled recorder. Using systematic sampling, data were recorded for a period of two years. Temperatures were analyzed for one summer and one winter month. Vertical distribution of the width of annual rings was analyzed for the period of the last 50 years for both earlywood and latewood as well as for total annual rings. Basic growth theories were outlined and the thesis suggests that none of these gives a completely satisfactory answer. Possible significance of temperature on the vertical growth distribution of annual rings was outlined. / Forestry, Faculty of / Graduate

This study is based on 68 permanent sample plots long established throughout the Coastal Douglas fir Region of the Pacific Northwest, in both natural and planted stands of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco). These plots, established by seven agencies, cover 27 acres of land and contain 13 thousand trees, of which 10 thousand had been located in the Cartesian system of coordinates. Trees were individually measured, usually every 5 years, during periods varying between 10 and 30 years. Four computer programs have been written in Fortran IV to compile detailed information about forest growth and yield, stocking and stand density, frequency distributions of tree parameters, their spatial arrangements and probabilities of mortality. Multiple regression techniques were used to determine relationships among mortality, and stand and site characteristics. The objectives of the study were to fully describe "regular" mortality caused primarily by competition in second-growth stands, and to develop some methods to facilitate and improve its prediction. The problem has been tackled by using both the stand approach and the tree approach. Results show that regular mortality can be described and predicted by making use of the stand parameters entering growth functions, i.e. density, age and site index. It is best expressed in number of stems per acre. However, first- and second-order linear models including these variables could not account for more than 43 percent of the variation in mortality in natural stands. Six groups of mortality tables are presented, indicating the annual probability of individual tree mortality by age classes, based on their relative size, increment, or position with regard to the stand in which they grow. These probabilities could be used to devise marking rules for thinning operations, and to replace or supplement competition formulae built into most forest growth simulators. As such, they serve in quantifying changes in the relative growth capability of each tree with time. All percentage diameter distributions of dead trees studied fit to negative binomial probability distributions. Spatial arrangements of dead trees were clumpy only in very dense stands, in mixed stands of Douglas fir and other conifers, or in stands affected by irregular mortality. Five methods are given to predict mortality on a stand basis. A new semi-stochastic stand model, based on mortality tables, is presented as a tool to investigate growth and mortality in actual or hypothetical forest stands. In addition to providing much information about mortality, its estimates are as precise as those from other current methods for yield prediction. The input consists of a tally of tree diameters and a height-diameter equation; the output is composed of histograms of dead tree diameters, maps of their most likely spatial arrangement, and stand growth and yield information for 10-year prediction periods. Moreover, the model allows probabilities of irregular and catastrophic mortality to be taken into account. / Forestry, Faculty of / Graduate

A comprehensive literature review of the factors affecting the survival of planted Douglas-fir seedlings is presented. Original data from operational planting trials was analyzed to determine the effect of some seedling, planting and environmental factors on survival. The use of 2+1 stock was found to result in increased survival of fall-planted seedlings, but not of spring planted seedlings. 1+0 stock showed comparatively good survival when spring-planted on sites with little brush and/or slash competition. The size of planting stock, and a subjective assessment of grade were not found to be related to survival after one growing season. Fall lifting dates from October 15 to December 2 were analyzed in relation to survival using regression analysis. Early-lifted stock was found to result in lower survival than the later-lifted stock. Lifting date had no significant effect on the survival of spring-planted seedlings. Planting dates from February 10 to June 10 in the spring and from October 14 to December 2 in the fall were analyzed in relation to survival using regression analysis. Survival was found to be significantly improved with later fall planting dates and early spring planting dates. Length of storage had no detectable influence on survival. The nursery origin of the seedlings was found to be significantly related to survival. Where ground cover competition was severe, slash-burning resulted in increased survival; where ground cover competition was light or non-existent, slashburning resulted in reduced survival. Heavy ground cover competition reduced the survival of both spring and fall-planted seedlings, except on north to east aspects. Elevation and aspect of the planting site were both found to be significantly related to survival. Planting in thick duff reduced the survival of spring and fall-planted seedlings. The survival of fall-planted seedlings was also reduced by planting in rolling topography, and on steep south to west aspects. Planting during sunny weather resulted in reduced survival. Planting during snowy weather reduced the survival of fall-planted seedlings only. Some genetic factors, such as origin of the seed, seed classification, and aspect and elevation of the seed collection areas compared to that of the plantation were analyzed in relation to survival with inconclusive results. The author concludes that no one factor is of overriding importance in all situations, but that all factors act and interact to varying degrees. Therefore in most cases it is very difficult to assign a specific reason for mortality. It is important that the relative importance of each factor under different sets of conditions be known. The key to better survival, therefore, is planning and forethought, to ensure that as few factors as possible are limiting to survival at any one time. Based on the data analyzed, some specific recommendations for improving the survival of planted Douglas-fir seedlings are presented. / Forestry, Faculty of / Graduate

The principal objectives of the study were to investigate geographic variation of, and relationship between, 1000-seed weight and cone-scale morphology and variation of germination percent of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco ) from within its natural range in Northwest America. One hundred twenty four seed sources representing eight climatic regions from British Columbia to California (lat. 38°50' to 53°37', long. 117°00' to 127°27') were collected in 1966 and 1968 by the International Union of Forestry Research Organizations, Section 22. From the seed samples, filled seed (which constituted 1000-seed weight) were selected using soft X-ray fluoroscopy. Five cone-scale measurements were taken; cone-scale width, bract width, cone-scale length, 1st prong length and 2nd prong length. The position of the bract in relation to the scale was rated. For germination testing, 56 filled seeds were selected to represent each of 12 trees in each of 114 provenances. The total of 76,608 seeds from 1,368 individual trees were sown untreated in two replications on ten relatively uniform nursery beds during May, 1969. Seed weights varied greatly. One thousand-seed weight increased clinally from low to high elevation and from north to south. Latitude appeared to affect seed weights more than elevation. Cone-scale characteristics differed significantly from tree to tree, provenance to provenance, as well as sub-region to sub- region. Cone-scale widths and lengths were only significantly different between regions. These characteristics again showed a clinal variation which increased from low to high elevations and from north to south in some regions, and revealed that latitude affected cone-scale morphology more than elevation. Thousand-seed weights were generally positively correlated with cone-scale size. Germination percent was significantly affected by latitude around 36 days after sowing, but this effect disappeared by 50 days. Elevation and longitude appeared not to affect germination percent during the observed period (0 - 92 days after sowing). The results of this study illustrate the importance of geographic origin as a source of phenotypic variability in Douglas-fir. / Forestry, Faculty of / Graduate

A comparative karyotype study was made of chromosomes in root-tip meristematic cells of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco germinants obtained from three Coastal (#1,3,22,) and one Interior (#28) sources distributed through 8°04" latitude. The somatic chromosome number in all provenances was 2n=26 or x=13. The morphological index was found to be the most useful criterion for separating the five metacentric, six submetacentric and two subtelocentric chromosomes of the basic set. A clinal increase from south to north in chromosome width (1.3), and volume (1.6), was noted among the chromosomes of the three Coastal provenances. The haploid chromosome complement of the Coastal provenance (#22) had 1.5 times more volume than the corresponding Interior one (#28), substantiating previous results as far as variation in nuclear volume and DNA contents are concerned. Gasguet (#3) provenance showed more dissimilarities regarding the length of the chromosome arms and secondary constrictions than the chromosomes of the other three provenances . / Forestry, Faculty of / Graduate

Seedlings from the International Union of Forestry Research Organizations (I.U.F.R.O) collections in 1966 and 1968 sampling the range of Douglas-fir from northern California to British Columbia were used to establish a provenance-progeny test at the University of British Columbia Research Forest in Haney. The study analyzed height growth in a total of 384 half-sib families representing 48 provenances. The objectives were 1) to estimate the degree of genetic variation between and within, provenances for height growth, 2) to estimate the additive genetic variance, 3) to estimate narrow sense heritability, 4) to estimate juvenile x mature correlation, and 5) to select the best provenances and progenies for the Haney planting site. Results from seed zone analysis showed that the most significant differences in the genetic variation in height growth of juvenile Douglas-fir trees was found in the relative sizes of the variance between provenances (Vp) and the variance between families within provenances (Vf/p). Provenances most adapted to Haney conditions exhibited Vf/p and Vep as the dominant contributors to the phenotypic variation. For less adapted provenances, Vp was of greater importance. In all zones the greatest component of variance was due to the variance of individual trees within families (Vep). Variance due to block x provenance interaction (VpxB) was the next largest variance between blocks (VB). Estimates for additive genetic variance and heritability for seed zones were quite high. Low values for their respective standard errors indicated high reliability in the results. High values of heritability indicated that there are opportunities for significant improvement by selection in Douglas-fir. Results from the juvenile x mature correlation analysis indicated that reliable selection of the best and deletion of the poorest provenances and families may begin at age five years. It is recommended that selection in seed zones 2 and 3 and the best provenances from seed zone 1 would yield the best results for the Haney site. As an example of genetic gain, a selection intensity of only one in four (25%) of the top individuals was chosen. Using this low selection intensity, figures obtained for genetic gain at Haney varied from 17.90% for two year to 10.96% for eight year height growth. Selection in the best provenance, of the best seed zone could increase total height growth by almost 33%. An additional increase of 70% is suggested if the best individual within the best provenance is chosen. Further gains in height growth are possible if higher selection intensities are used. / Forestry, Faculty of / Graduate

Seedlings and one-year-old trees of Douglas-fir (Pseyidotsuga menziesii) were grown in chambers with atmospheres maintained at 0.03% to 5.0% CO₂ (by volume). Carbon dioxide treatments were given in conjunction with daylengths of 8 or 16 hours and light intensities which varied from 3.4 mW cm⁻² to 7.2 mW cm⁻² (400 - 700 nm). The duration of treatment varied from 30 days to 12 weeks. When plants were treated with 0.1% CO₂ both seedlings and trees showed enhanced growth, as demonstrated by increases in dry weight and internodal elongation. CO₂ enrichment caused growth enhancement to a degree that other factors became limiting, e.g., irradiance. Carbon dioxide concentrations of 1.0% CO₂ and higher generally inhibited growth, as shown by decreases in internodal elongation, dry weight, and leaf area. Plants grown under high carbon dioxide levels ceased active growth and exhibited increased budset and frost hardiness. High CO2 levels appeared to override photoperiodic control of budset by promoting budset even under warm temperatures and long days. CO₂-induced frost hardiness appears to require an active metabolism, indicating that the mode of CO2 action is through increased production of cryoprotectents, such as amino acids and sugars. In some cases, carbon dioxide may substitute in part for the light requirements of photosynthesis when light is limiting. Thus, an increase in daylength may reduce the level of CO₂ required for a particular effect, e.g., the required CO₂ levels for inducing frost hardiness are reduced from 1.0% to 0.1% CO₂ if long days are provided. Plants which have been grown under normal air (0.03% CO₂) have higher photosynthetic rates than enriched plants when all plants are measured in normal air; the concentration under which plants are measured appears to have more effect on photosynthetic rates than the CO₂ concentration under which the plants are grown. Under long days and high CO₂ (1.0% CO₂ and higher), plants show reduced diffusion resistance, but the beneficial effects on photosynthesis due to potential reduction of CO₂ diffusion resistance are lost as a result of increased rates of respiration under high CO₂. Thus, the enhancement of growth under 0.1% CO₂ and the inhibition of growth under 1.0% CO₂, appear to be mostly related to differences in respiration under the various carbon dioxide treatments. All effects of carbon dioxide may not be due to gas exchange characteristics alone, but may result from changes in levels of growth inhibitors, such as abscisic acid. The effects of CO₂ on growth and development were examined over a range of CO₂ concentrations. Over the entire range CO₂ was found to effect both growth and development and the processes underlying growth and development. / Science, Faculty of / Botany, Department of / Graduate