Harvesting costs were determined for commercial thinning of young stands to
achieve vegetation and wildlife objectives. This included replicated comparisons of
thinning treatments. Treatments were defined based on residual tree stocking after
thinning. Study procedures were developed and evaluated to improve statistical
relevance. Multiple linear regression models were used to...
The objectives of this study were to determine: 1)
differences in average wood quality and strength properties
of clear-wood specimens sampled from juvenile, transition,
and mature wood zones in Douglas-fir (Pseudotsuga menziesii
(Mirb.) Franco) trees from known forest sites; 2)
relationships among wood quality properties [specific
gravity (SG), rings per...
There are a number of wood properties which affect the quality of forest products such as lumber and pulp. Of these, wood density is considered by some to be the single most important physical characteristic because it is an excellent predictor of strength, stiffness, hardness, and paper-making capacities. Accurately assessing...
• A technique for measuring in vitro respiration was investigated to understand why rates were higher than those reported in vivo and to elucidate trends within mature Pseudotsuga menziesii (Douglas‐fir) trees.
• Extracted increment cores were divided into 3–4 radial depths and a gas chromatograph was used to compare respiration...
Live western larch, Larix occidentalis Nutt., a tree species resistant to the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, produces the monoterpene 3-carene in higher concentrations compared to Douglas-fir, the preferred host of D. pseudotsugae (Reed et al. 1986). The inhibitory effects on attraction to aggregation pheromones and toxicity of 3-carene to...
The two-parameter Weibull function was used to predict forest stand diameter distributions and growth. Diameter distribution models were developed for even-aged Douglas-fir stands, 20 to 40 years old, in Oregon and Washington. In order to test if the two-parameter Weibull function can adequately describe the diameter distributions of such stands,...
A field study was conducted to determine the impact of microclimate and vegetation on
survival and growth of planted Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) at a pinegrass (Calamagrostis rubescens Bucki.) dominated clearcut in the Interior Douglas-fir Zone of south-central British Columbia. The study focussed on (1) the water balance of...
Chapter 1 Growth and Survival of Root-Wrenched Douglas-fir Seedlings Root wrenching of seedlings (severing the roots 15 cm below the soil surface) was investigated as a nursery practice to improve growth and survival of field-planted Douglas-fir from six local seed sources
in the Pacific Northwest. At lifting, shoots of wrenched...
The goal of this thesis was to determine the physiological mechanisms that link adverse preplanting treatments of Douglas-fir, such as exposure and root pruning, to the phenomenon of transplanting shock. The objective of experiments 1 and 2 was to measure the effect of exposure and pruning on the physiology and...
The effect of lifting date and root-pruning treatments on
water potential, root regeneration, and shoot growth of six-month-old
and three-year-old Douglas-fir seedlings bare-root transplanted
into a growth chamber, and sawdust bed, respectively, was studied.
Root growth in six-month-old and three-year-old seedlings was
highest in February and August respectively. Survival was...
Significant post planting mortality of young conifer seedlings often occurs on drought prone sites because seedlings fail to either establish, or maintain favourable water relations. Survival is contingent upon growth which occurs when turgor pressure is above a threshold level. Since growth after planting is influenced by nursery cultural practices,...
To determine if squirrels (Sciurus douglasii var.) cut cones before the seeds are ripe, a series of collection points was established in the Willamette Valley and the Cascade Mountains in the summer of 1954. The areas were inspected at intervals during August, September and October of 1954, and freshly cut...
Douglas-fir and western hemlock growth and stocking were examined on two neighboring clear-cut watersheds in the Western Cascades of Oregon and related to the intensity of burning and logging disturbance, habitat type, soil type, aspect and the influence of percent cover of both invading Ceanothus species and residual Acer circinatum....
Across western Oregon, Washington, and British Columbia, forest management practices over the past century reduced the amount of late-successional forest while
simultaneously increasing the amount of young (less than 80 years old), managed
Douglas-fir (Pseudotsuga menziesii) dominated forests. Recently, concerns over loss of late-successional habitat pushed management objectives on public...
From a preliminary 1969 foliar analysis, eight provenances were chosen from the sixteen included in a region-wide, reciprocal Doulgas-fir provenance study for further study of variation in foliar nutrition. In the fall of 1969 separate foliar samples were collected from ten
trees per provenance at each of ten plantations ranging...