One of the key factors in the site classification of the biogeoclimatic ecosystem classification is soil nutrient regime. Soil nutrient regime (SNR) represents the amount of essential soil nutrients available to plants over a period of several years. SNRs classes are assessed based on field identifiable (qualitative) criteria, not using quantitative measures. There have been several studies that attempted to quantitatively characterize regional soil nutrient gradients in the Coastal Western Hemlock (CWH) zone. In the study summarized here, the soils are influenced by a perhumid cool mesothermal climate. The objective of the study was to examine relationships between soil chemical properties and field-estimated SNRs.

The superior growth of Grand fir (Abies grandis) compared to Douglas-fir (Pseudostuga menziesii) on suitable coastal sites has previously been recognized on the basis of qualitative observations with little empirical evidence. For example, D.E. McMullan (1977, pers. comm.) reported 18% higher volume for a grand fir tree of the same height and age as a 108-year old Douglas-fir plus tree (No. 622) This study was undertaken by Bernardy (1988) to examine possible differences in the growth of grand fir and Douglas-fir growing in a mixed 40-year-old plantation of unknown origin. Trends in height, diameter and annual volume increment between the two species over time were examined. Expected growth performance (i.e. volume and form) of each species was inferred from trends identified at time of sampling.

In British Columbia, humus form identification is widely use to infer the level of plant-available soil nutrients. This identification is based on field-observable (morphological) features. We recognize three major humu forms: Mors, Moders, and Mulls - which are differentiated according to the type of F horizon, and the presence/absence of organic matter-enriched Ah horizons. Mors represent humus forms where decomposition is dominated by fungi, with slow decomposition rates and accumulations of organic matter on the soil surface. Mors are characterized by the presence of a Fm (m - mycogenous) horizon. In contrast, Mulls represent humus forms with high rates of decomposition and faunal activity resulting in organic matter being intimately incorporated into the upper mineral soil layer instead of accumulating on its surface. Intermediate on the humus form gradient from Mors to Mull are the Moders. Moders are similar to Mors in that they have accumulations of organic matter on the surface of the mineral soil but decomposition is not fungus dominated, so they lack the diagnostic Fm horizon. The central concept of the Moder is represented by the Leptomoder, which is characterized by a Fz (z - zoogenous) horizon with an active population of soil meso- and microfauna, fungal mycelia are not present or present in small amounts. When both fungal mycelia and faunal droppings can be found, but neither clearly predominate over the other, an Fa (a - amphimorphic) horizon results. Fa horizons are characteristic of Mormoders, an integrade between Mors and Moders. Considering the prevalence of Mormoders and Leptomoders in B.C. and the difficulties in identifying Fa horizons, the aim of this study was to determine whether the morphological features used to differentiate these two Moder humus forms reflects differences in their physical, chemical and biotic properties.

Thesis (Ph. D.)--Oregon State University, 1994. / Typescript (photocopy). Includes bibliographical references (leaves 109-125). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Breast height radial growth of 165 western red cedar (Thuja plicata Donn), 14.5 western hemlock (Tsuga heterophylla (Raf.) Sarg.) and 33 Douglas fir trees (Pseudotsuga menziesii (Mirb.) Franco), in young natural stands on the eastern side of the University of British Columbia Research Forest near Haney, B.C. was analysed. Individual tree parameters measured included breast height diameter, total height, age at breast height, radial growth over last five and ten years, crown width, live crown length, tree class, live crown ratio, height/age ratio, crown width/breast height diameter ratio, and height/ crown width. Stand parameters measured were number of trees per plot, average breast height diameter of plot, and basal area per acre of plot. Plots were of variable radius as determined in prism cruising. Growth was investigated from results of simple correlation coefficients and several multiple regression analyses computed on an IBM 7040. Causes of variation in growth were assessed by studying interaction of variables affecting growth patterns. Individual species have distinctly different modes of growth. Species react differently to changes in stand density. Radial growth can be determined from measurements of tree crowns; and crown development reflects changes in stand density. Difference between species are found as crown development varies with stand density changes. Crown dimensions of western hemlock are least sensitive to changes in stand density as measured by basal area per acre, crown width/breast height diameter, live crown ratio, or height/crown width. An understanding of how crown dimensions change with variation in stand density can be used to refine predictions of tree radial growth derived from crown measurements. / Forestry, Faculty of / Graduate

Western hemlock seedlings were grown for 8 months in a greenhouse with fertilizer amendments of N, P, N+P, and lime. Humus material was used as a growth medium. It was collected from low-productive sites identified by Lewis (1985) as the cedar-hemlock phase of the Thuja plicata - Tsuga heterophylla - Gautheria shallon - Rhytidiadelphusloreus ecosystem association unit designated as S1CH , on his ecosystem maps of Tree Farm Licences 6 and 25, which are located on northern Vancouver Island. A combination of 100 kg/ha N and 150 kg/ha P produced the most favourable seedling growth and foliar nutrient status. N or P added separately at these rates also gave superior seedling growth compared to the control. Neither lime, nor high rates of N (at 300 kg/ha with or without P) increased seedling growth. High N additions also restricted root development. N fertilization reduced foliar P concentrations, and P addition decreased foliar N concentrations. Foliar Mg concentrations increased when P fertilizers were added. N and/or P additions caused a decrease in foliar B concentrations. A combination of N and P increased foliar Zn concentrations and S, but reduced Mn absorption. Foliar R was inversely related to seedling productivity. Management recommendations for the S1CH sites include fertilizing with P, and increasing available N either by cultivation to increase mineralization or by low rates of N fertilization / Land and Food Systems, Faculty of / Graduate

The fixed bed drying of western hemlock and Douglas-fir biomass particles at temperatures ranging from 50��C to 200��C and air velocities from 0.3 to 0.9 m/s was investigated. The objectives were to describe the drying characteristics of the particles, fit a model for thin-layer drying, and develop and test a deep bed drying model based on the thin-layer model. The effects of temperature and air velocity were determined in a bed approximately 1.3 cm in depth and a model for the drying curve was developed. The thin-layer model was then used to predict what would happen in a deeper bed. Model results were compared to drying curves measured in a 23-cm-deep bed. The deep bed model predicted both the experimental drying times and the moisture and temperature profiles in the bed. / Graduation date: 2013

Response to fertilization is a function of the degree to which nutrients are limiting growth, the capacity of individual trees to respond to nutrient inputs, the degree to which other factors limit growth, and the possible extrinsic effects of treatment (e.g., root mortality due to fertilizer-induced soil pH effects). Recognition and examination of these factors is essential if response to fertilization is to be predictable. Over the past 25 years numerous western hemlock fertilizer trials have shown responses ranging from negative to positive with no clear trends. Theories for this erratic response include: (a) different nutritional requirements during different stages of stand development; (b) high native N availability or low supplies of other nutrients (P and S, in particular); (c) differential adverse effects of N fertilizers on surface roots, mycorrhizal populations and P nutrition; (d) a requirement for slow release N; and (e) induced water stress. The objective of this study was to develop site-specific guidelines for western hemlock fertilization decision-making for industrial use. This study reports on the first and third growing-season response to two different fertilizer treatments, and identification of possible relationships between fertilizer response and site and stand conditions.

When making decisions on which areas to harvest in a sustained yield, even-flow manner in mountainous areas such those in coastal British Columbia, it is important to know how timber productivity changes with elevation. This information allows foresters to decide at what elevation to start increasing the rotation age and to decide at what elevation sustainable harvesting becomes infeasible due to low productivity. Since Pacific silver fir (Abies amabilis Dougl. ex Forbes) has an elevation range that extends from sea level nearly to the tree line (0 m to approximately 1,650 m; from the Coastal Western Hemlock zone, through the Mountain Hemlock zone; to the lower limits of the Alpine Tundra zone), productivity-elevation relationships are especially important. To acquire quantitative measures of productivity decrease with increasing elevation a regression equation relating site index (the height of the dominant trees at a base age of breast height age of 50 years) to elevation in southern coastal BC was developed. In turn, we used this regression as an input into the height driven yield model named the Variable Density Yield Prediction model (VDYP). The use of the VDYP model allows the site index values to be translated into actual productivity measures (e.g., volume per hectare, mean annual increment at culmination age).