The phenolic extractives from western hemlock wood (Tsuga heterophylla (Raf.) Sar.) have been examined. The total extractive content of the wood amounted to 1.5% of the dry weight. A leucoanthocyanidin and two lignans, conidendrin and hydroxymatairesinol, were isolated from the phenolic fraction by precipitation of a methanol solution into peroxide-free ether followed by separation on silicic acid-calcium sulphate chromatobars. The pigment produced by acid treatment of the isolated leucoanthocyanidin was shown by spectral studies and alkaline degradation to be a mixture of cyanidin and an unidentified anthocyanidin. The two anthocyanidins had identical Rf values in different solvents and similar ultra-violet spectra in ethanol-hydrochloric acid solution but the shift of the absorption maxima caused by addition of aluminium chloride was negligible in the case of the unknown compound and amounted to 30 mµ for cyanidin. Similar separations of the absorption maxima after complexing with aluminium ion were observed with the 3-methyl and 3-isopropyl ethers of the two anthocyanidins. The alkaline degradation products from the leucoanthocyanidin contained protocatechuic acid but no phloroglucinol. Degradation products of phloroglucinol, however, were present in the reaction mixture. These results suggested that the leucoanthocyanidin occurred in the wood in dimeric form and that alkaline degradation of this structure produced a symmetrical hexahydroxyhenzophenone derivative which split up directly into fragments identical to those obtained from phloroglucinol under the same conditions. New information on the structure of hydroxymatairesinol was obtained by comparison of the infrared spectra of the fully acetylated hydroxymatairesinol with that of the reduced compound and by neutral potassium permanganate oxidation of trimethylhydroxymatairesinol. The results obtained were in good agreement with only one of the two structures previously proposed for hydroxymatairesinol by other workers. The NMR spectra of hydroxymatairesinol and structurally related compounds were compared, but the interpretation of the spectrum of hydroxymatairesinol proved to be difficult because broad, incompletely resolved lines were obtained due to the complexity and asymmetry of the molecule. / Science, Faculty of / Chemistry, Department of / Graduate

A canker on the main stem of oppressed western hemlock (Tsuga hetero hylla (Rafn.) Sarg.), 1 to 3 inches in diameter at breast height, was found at Powell River and Tumour Island, British Columbia. The canker is irregularly elliptical, with a conspicuous resin exudation in the early stages. The canker appears to be annual. A species of Cephalosporium (Fungi Imperfecti, Moniliales) was consistently isolated from cankers collected at Powell River. The pathogenicity of the organism has not been proven to date. The growth and hyphal characters of the organism, and the temperature-growth relations of the organism in culture are described. The conidial apparatus of the organism was investigated. Attempts to produce the perfect stage in culture were unsuccessful. / Science, Faculty of / Botany, Department of / Zoology, Department 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

The vertical rate of spread of dwarf mistletoe was studied in two actively growing, young hemlock stands. This was done by determining the height and age of successive oldest and highest female infections. The rate of spread was calculated by dividing the sum of the heights of advances by the total number of years lapse between successive advances. The mean vertical spread rate was 2.1 ± 0.1 ft./yr. in a relatively open stand and 1.0 ± 0.1 ft./yr. in a relatively dense stand. The mean rate of tree growth during the maximum growth phase in the open stand was 2.5 ft./yr. and for the dense stand 1.5 ft./yr. However, over the past 25 years, the growth rate of the trees in the open stand was 1.9 ft./yr. and for the dense stand 1.1 ft./yr. The number of new infections per year increased geometrically, doubling every four years in both the dense and open stands. However, the geometric increase levelled off six years ago in the open stand and five years ago in the dense stand. During the maximum growth phase of hemlock in an open and dense stand, the most photosynthetically active upper portion of the crown remains free of mistletoe infection. Until the senescent phase is reached, the trees can be expected to outgrow the mistletoe and intensification will be restricted to the lower portions of the crowns. It is tentatively concluded that provided there is no overstory seed source and no disruption of the natural stand, such as thinning, dwarf mistletoe on hemlock will not become serious until the rate of height growth of the trees falls below the rate of vertical spread, i.e., not until after the presently accepted rotation age. / Forestry, Faculty of / Graduate

The number, height and age of western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones) infections were recorded in two western hemlock (Tsuga heterophylla (Raf.) Sarg.) stands (44 and 130 years old) located on similar sites on the University of British Columbia Research Forest at Maple Ridge, B.C.. The rapid decrease in numbers of infections with infection age was shown to be largely due to infection mortality. The rate of intensification of the disease expressed as "doubling time" was estimated to be 40 or more years in both stands. Also estimated was a rate of vertical spread of .15 metres per year. The results differed markedly from those of other studies in similar stands, which generally predict "doubling times" of 2 to 4 years and vertical spread rates of up to .5 metres per year. / Forestry, Faculty of / Graduate

Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 53-56). Also available via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 94-102). Also available on the World Wide Web.

No description available.

Eastern hemlock (Tsuga canadensis [L.] Carr.) is a foundation species that occupies a unique niche in forest ecosystems and which often forms pure stands throughout the eastern United States. Throughout the last half of a century, widespread mortality of T. canadensis had been occurring with the introduction of the invasive pest, hemlock woolly adelgid (Adelges tsugae Annand) (HWA). HWA now threatens to destroy millions of hectares of hemlock dominated forests and to disrupt its associated ecosystems. In order to determine how HWA impacts hemlock physiology, three sites with various degrees of infestation were chosen and half of the trees at each site were treated with imidacloprid (Merit® 2 F, Bayer, Kansas City, MO) while the rest were left untreated. Needle gas exchange was assessed monthly using a LI-COR 6400 portable open path gas exchange system (LI-COR Inc, Lincoln NE). Chlorophyll fluorescence and bud break were also characterized for all trees at two of the three sites. After one complete growing season, we found a slight increase in photosynthetic rates (4.98 %), increased bud break at Fishburn (562 %) and Mountain Lake (25.6 %) sites, and no change in chlorophyll fluorescence for imidacloprid treated trees. These results suggest that HWA is causing tree mortality largely through a reduction of leaf area and not a reduction in leaf level photosynthetic capacity. By quantifying the physiological response of T. canadensis to HWA, better insights can be made into understanding tree decline as it relates to HWA. / Master of Science

No description available.