Reforestation of Pacific Northwest forest-lands with western hemlock has been hindered by unexplained plantation failures.
The purpose of this thesis is to provide information that will help in determining the cause of seedling damage and mortality. The studies focused on the relationship between xylem water potential, xylem cavitation and the...
I studied selection of winter den sites by northern flying squirrels (Glaucomys sabrinus) in forests of the Oregon Cascades. Fifty-six squirrels were radio-collared in three managed, 80- to 1 30-year-old Douglas-fir stands on the Umpqua Nationa Forest during the winters of 1994-95 and 1995-96. Squirrels were located at their den...
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional
watersheds is needed to provide a foundation for forest management strategies
aimed at conserving native biodiversity. I examined influences of environmental variability
and disturbance history on forest structure and composition in the Cummins Creek
Wilderness, located on the central Oregon...
Most recent research on stream amphibians in the Pacific Northwest has focused on associations with reach-level or stand-level environmental features. Little is known about landscape-level distributions of these species or landscape-level aspects of their life-histories. I used a watershed-wide sample and logistic regression to develop models and maps of probability...
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...
Cold hardiness and phenology are important adaptive
traits for perennial plant species in temperate climates.
Timing of growth, dormancy, and associated cold acclimation
and deacclimation represents a delicate balance between
maximizing growth under favorable conditions and minimizing
frost damage under unfavorable conditions. Geographic
patterns of genetic variation in adaptive traits,...
Understory conifer regeneration needs to occur beneath conifer-dominated
canopies if two-storied or uneven-aged structures are to be considered for western
Oregon Coast Range stand management. To ensure adequate numbers of seedlings
to meet stocking or habitat structure objectives, planting may be a solution. We
undertook a multi-level study to determine...
Tree seedling establishment and growth were studied in experimental canopy gaps to determine the effect of structural and environmental heterogeneity on species dynamics within mature and old-growth Douglas-fir forests in the Cascades of central Oregon and southern Washington. Factors examined included forest age, gap size, within-gap position. substrate, year of...
The overall objective of this study was to evaluate biomass production and soil ameliorative potential of alley farming in sub-humid India. Effect of the cutting height (40, 80, 120, 160 cm) of Leucaena hedges and root barriers on biomass yield of Leucaena and maize and wheat crops were examined. Trees...
Transplant shock was induced by applying a range of soil water contents to unstored and cold-stored two-yearold (2+0) bareroot Douglas-fir seedlings graded by root volume. Moisture stress had the greatest influence on
morphological characteristics commonly associated with transplant shock. Terminal growth, lateral growth, stem diameter growth, and needle length increased...
