Juvenile Douglas-fir, ponderosa pine, and whiteleaf manzanita
growth in southwest Oregon varied with density of co-developing
manzanita and presence of herbaceous cover. Plant xylem pressure
potential and stomatal conductance of each species was responsive
to competition-induced depletion of soil water. Rates varied among
species. The best correlations with growth usually...
This thesis examines the competitive aspects of Douglas-fir trees growing with two commonly associated competitors--red alder and grass--at varying densities. Two Nelder plots in three different environments in the Oregon Coast Range were studied. The sites represented the warm, dry climate of the Willamette Valley; the warm, moist climate of...
This thesis examines the 8-year growth trend of
Douglas-fir (Pseudotsuga menziesii (mirb.)Franco), ponderosa
pine (Pinus ponderosa Dougl. ex laws.), and whiteleaf
manzanita (Arctostaphylos viscida Parry). Manzanita stands
ranging from 1700/ha to 27000/ha density were grown among
mixed conifers of the same age, which were planted in 1981
at 250x250 cm...
Southwest Oregon presents an environment of hot dry summers, cool moist winters, and rocky, shallow soils. The establishment of conifer plantations in this region presents challenging problems for initial seedling survival and subsequent growth. Three areas of concern include early conifer growth after seedling establishment, growth of competing hardwoods within...
General outcomes of this study show that early growth of planted red alder is often slowed in the presence of neighboring vegetation, and overwhelmingly by salmonberry, a common associate in disturbed Oregon Coast Range habitats. Additionally, young red alder plantations located in
riparian areas may be highly susceptible to frost...
Forest managers of public lands in western Oregon and Washington have become increasingly interested in creating additional conifer cohorts in young, even-aged, second-growth Douglas-fir stands. The purpose of our research was to assess the establishment, survival, and growth of naturally-regenerated and underplanted conifers 10-13 years after overstory thinning and understory...
The growth of western hemlock during the first four
years of seedling establishment was examined in a competitive
environment in which seedlings were exposed to various types
of animal damage and salmonberry and/or alder competition.
The study utilized an existing Nelder/replacement series
experiment which focused on the competitive effects among...
Northeastern Oregon geology and climate provides moderately productive conditions for forest management and timber production. Although site preparation and planting are commonly used silvicultural practices, little research exists on the efficacy of specific forest herbicides and responses of seedling survival and growth in this region. This research seeks to improve...