An inventory of the most important indigenous and exotic Salix clones for basket making was carried out in Hungary. Eleven clones were selected from those presently growing in various parts of the country. The vegetative and generative characteristics of the shoots were described. Interspecific hybridization was carried out using five different combinations. The germination of Salix seed was studied by taking a series of photographs. Vegetative propagation by means of shoot cuttings and by "T" bud grafting were tried. A selection method was used for evaluating the different clones within the country. Five experimental plantations were set out on the more important soil regions and the eleven clones were planted in randomized blocks, each 10 by 10 meters in size. Each clone was replicated four times and 170 cuttings of each were planted in a block. The height growth of the 5th and the 10th ramets in each row were measured bi-weekly during the growing season in 1955 and in 1956. More than 100,000 height measurements were recorded. The influence of the clone, year, and locality on the average height attained was evaluated by means of an analysis of variance, and an attempt was made by using the components of variance to estimate the heritability. The simple correlation coefficients were calculated to approximate the degree of association of the average tree height, weight and volume of different clones in the five localities during the years 1955-1959 inclusive. Form of sprouts, cellulose content of one-year-old shoots, and meteorological conditions were studied. Experiments were undertaken concerning spacing and fertilization as part of the basket-willow improvement work. / Forestry, Faculty of / Graduate

Photogrammetry has become increasingly important in the practice of forestry. Recently, the trend has been toward the development of photo-mensurational techniques for direct estimation of timber resources. The purpose of the present study was to assess the possibility of applying aerial stand-volume multiple-regression equations for the application of photo-mensurational techniques on several kinds of air photos. Field data were collected from sample plots located in the U.B.C. Research Forest at Haney as well as from the forest on the campus of the University of British Columbia, in Vancouver. Modifications in technique for the determination of tree height, crown width and crown closure were developed by the writer and are described in this study. Multiple linear-regression equations were used for the analysis of data. Application of the Electronic Computer Alwac III-E to solve all the multiple linear-regression equations is described briefly. Ease of typing was evaluated subjectively. The present study has indicated: (1) Using a spherical densiometer, a ground estimate of crown closure in per cent resulted in an over-estimate, as compared with the photo-estimate. (2) Tree count could not be used effectively as an independent variable in the construction of the photo-volume equation. (3) Best results were secured when photographs: were taken with a 12-inch focal length and a flying height of 15,600 feet above sea level. (4) For the construction of photo-volume tables, height, crown width and crown closure should be used as independent variables, especially when more than one interpreter is involved. (5) No significant differences were found among photographic papers or finishes used for the determination of photo volume. (6) Photography with a Representative Fraction (RF) of 1:15,840 should be satisfactory for forest typing. (7) The greatest variation was among photo-interpreters. (8) Photo-interpretation could be improved by the standardization of photo-interpretation procedures. / Forestry, Faculty of / Graduate

Even-aged well stocked aspen stands in Northern Alberta were sampled in order to derive "normal" yields per acre for number and size of trees, basal area, and various measures of volume. The stands occur chiefly on three qualities of site which have been classified into Pair, Medium and Good by the average height of dominant trees at 80 years. Exceptionally high mortality per decade is characteristic in fully stocked young aspen stands and the relation of number of trees per acre to average diameter is markedly different from the trends found by investigators for other species., A table of stand density units was constructed to permit the, rapid calculation of stand-density index when average diameter and number of trees per acre have been determined. The mean annual cubic volume growth on medium sites is maximum at age 40. For merchantable cubic and board feet, growth reaches a peak at 85 and 130 years respectively. Data from two other regions show that the amount of cull is high in aspen trees above 80 years of age, this indicates that the wood should be utilized before a stand-age of 130 years is reached if maximum return in board foot volume is desired. By 140 years aspen stands show signs of breaking up. The hardwood stands measured were composed mainly of aspen but both white birch and black poplar occurred on many of the plots. The growth of the black poplar is only slightly less than that for the aspen. It has consistently lower volumes per tree which permits the use of aspen volume tables when correction factors are applied. / Forestry, Faculty of / Graduate

No abstract included. / Arts, Faculty of / Vancouver School of Economics / Graduate

No abstract included. / Forestry, Faculty of / Graduate

Forest planning is characterised by the necessity to satisfy a series of long term objectives and yet still to meet a series of short term objectives. This problem of conflicts is particularly pertinent to the Province of British Columbia where the forest ownership and the forest operator are each, primarily concerned with different time spectra. Further, the demands that are being made on the forest resource are becoming ever more stringent and demanding as the political and environmental awareness of the public increases. The need to consider multiple objectives in the planning process causes the inadequacies of many of the earlier models to be highlighted. A new series of models for forest planning is called for. The development of operations research, techniques and improved computers has facilitated the introduction of a new series of planning models. Many models have been developed using the optimising techniques of linear and dynamic programming for example, but the technique that, through its flexibility and latitude for variation in the basic assumptions, holds the most promise is simulation. Under the conditions of British Columbia, the forest firm, which is the main influence on the forest resource and links the natural environment with the socio-economic environment, is the natural planning unit. The firm is constrained by the superior environments and it is the responses of the firm to changes in either that affects the flow of goods and services from the forest. An analysis of the firm shows that if a systems approach is adopted the planning and productive stages of the firm may be defined in a suitable manner for the construction of a computer simulation model. The model may have several stages of operational development and may be used for different purposes as it is developed towards full operational use. The ultimate stage of development will only be known when the detailed construction of the model is undertaken. This thesis outlines the need for the model and develops it to a pre-construction stage. The major steps and processes that must be described for construction of the model to the first development stage are outlined. The first development stage is that of a forest management game. The sources of the data and the initial limitations of the model and the output are given and the subsequent development stages described. / Forestry, Faculty of / Graduate

A great many kinds and forms of volume equations can be found in any review of the literature on this topic. At least four procedures are available for comparing volume equations to judge which one gives the best estimate of volume. These procedures are evaluated in this thesis for seven volume equation forms: [equation forms omitted] and two new methods are introduced: (l) Taylor's series for estimating errors and (2) sum of absolute deviations. Comparisons of above equations with different procedures were carried out for two species, lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss.). Merchantable volumes of both species were described by three subsets of data which were grouped according to the following Girard form quotients for 32 foot logs: 1. 80+ 2. 70-79 3. <69. It was found that none of the presently available procedures, including the two new ones, can by itself indicate the best tree volume equation, which led to the conclusion that whenever more than a quick approximation is required, at least two of the methods should be used simultaneously. Both relative and absolute measures of residual variation must be considered. It is concluded that choice of equation form depends very much on the specific requirements of the research or operational project involved. / Forestry, Faculty of / Graduate

Variations in western hemlock tree and stand growth were analysed to determine the relative importance of causative factors. Four phases in a stand's life-cycle were investigated (seedling establishment, juvenile growth, early stand formation, and middle-age). Detailed analyses of tree growth were made at the time of early stand formation (25 to 35 years). Stand growth and yield data (15 to 160 years) were analysed by multiple regression methods to ascertain the effects of varying density regimes on time and magnitude of maximum wood volume per acre. In all stands studied, tree height was unaffected by variations in stand density. Detailed analyses of current breast-height radial growth indicated that the factors of antecedent growth, tree d.b.h., stand density, age, and site quality were of decreasing importance in the order listed. Statistically, the best measures of stand density were ratios of crown width and live crown length with total tree height, although stand basal area per acre was only slightly less significant. Stand fertilisation with nitrogen stimulated tree radial growth and changed the relative concentrations of foliar nutrients within the crown. Limited (15 trees) biomass studies indicated that production per unit area of above-ground tree weight (oven-dry) increased linearly with greater stand density. Yield increased directly in proportion to the fraction of area occupied by trees (stocking) and curvilinearly with degree of crowding (stand density) within the area occupied. Mean annual net volume increment did not culminate even at stand densities of 500 square feet of basal area per acre. Both intensive and extensive forest management was discussed. Within the Coastal hemlock zone there could be many advantages for a shelterwood regeneration system and two-storey high forest with western hemlock as a supplementary species. / Forestry, Faculty of / Graduate

A new taper equation is presented, log d = b₀ + b₁ log D + b₂ log 1 + b₃ log H where d is the diameter inside bark in inches at any given 1 in feet,D is the diameter breast height outside bark in inches, 1 is the distance from the tip of the tree in feet,H is the total height of the tree in feet and b₀,b₁,b₂ and b₃ are the regression coefficients. Two methods of deriving a compatible system of tree taper and volume equations are discussed.One method involves conversion of the logarithmic taper equation into a logarithmic volume equation.The other involves the derivation of the logarithmic taper equation from an existing logarithmic volume equation to provide compatabllity in volume estimation and at the same time ensure as a good fit as possible for the estimation of upper bole diameters (taper). Tests for precision and bias of volume estimates, carried out on the British Columbia Forest Service taper curves and logarithmic volume equations,indicate that the latter approach is preferable to the former. / Forestry, Faculty of / Graduate

An understanding of the water balance of forest ecosystems is of benefit to foresters who manage second rotation stands. Maximizing the mean annual increment can be better realized if recognition is given to the importance of the water balance. One component of the water balance, root zone drainage, is not only important, but also difficult either to measure or calculate. In this study, root zone drainage during a two-week drying cycle was monitored by a method based on Darcy's Law. To implement the method, a tensiometer-pressure transducer system was developed which constantly monitored the soil water potential at five soil depths. The system was easily installed, required minimum maintenance and measured the potential of the soil water to within ± 1.8 cm. H₂O with a response time of less than five seconds. The cumulative root zone drainage for the two-week period was 11.72 mm. with an estimated maximum error of the daily drainage of ± 1.30 mm./day. Comparable root zone drainage derived from an independent but simultaneous evaluation by the water balance method was 9.33 mm. with an estimated maximum error of the daily drainage of ± 2.kl mm./day. Both positive and negative drainage to the root zone was observed. The negative drainage (water moving into the root zone) provides a supplementary supply of water to the root zone, thereby reducing the possibility of a soil water deficit occurring. / Forestry, Faculty of / Graduate