In the thinning theory, the hypothesis that the stand
growth is unaffected by the density over a broad range of
densities is generally accepted today.
In this study three different measures of stand density
were used in basal area growth and volume growth
multiple regressions in even-aged managed stands, searching...
A silvopastoral system using a Douglas-fir
(Pseudotsuga menziesii) tree crop and subclover (Trifolium subterraneum) as a nitrogen-fixing forage crop was
investigated near Corvallis, Oregon, during 1983-1985.
Treatments included all possible combinations of three
planting patterns (no trees, trees planted 2.5 m apart in a
grid, and clusters of five trees...
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...
Effects of tanoak (Lithocarpus densiflorus) on early
growth, morphology, and physiology of Douglas-fir
(Pseudotsuga menziesii) were studied to determine
developmental characteristics of young stands and
mechanisms of competition. Growth, leaf area, and biomass
of Douglas-fir, tanoak, and shrubs / herbs were monitored
for six years after establishing a gradient of...
Using existing data from untreated research plots, we developed equations
for predicting 5-yr diameter-growth rate (ΔD₅), 5-yr height-growth
rate (ΔH₅), and 5-yr mortality rate (PM₅) for Douglas-fir [Pseudotsuga
menziesii (Mirb.) Franco] in the coastal region of the Pacific Northwest.
These equations are revisions of the equations constructed in 1995–1997
for...
Stem form development of trees in response to wind has been established in the literature to be a response to stem sway induced by the wind. The response is manifested in modifications to height and diameter growth which strengthen the stem against wind stresses. Experiments in the literature show that...
The overall purpose of this study was to examine the root and shoot development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings at two distinct time periods in seedling establishment (after I and 3 growing seasons) in response to fertilizer, stock size, vegetation control, and soil moisture treatments. Two separate experiments...
The relative influences of stand structure and topographic
variation on volume growth, photosynthetic surface area,
and stem growth efficiency were determined for six 17 to
23 year old well stocked stands in the central Oregon
Coast Range. Plots were assigned to topographic classes
(aspect, slope steepness, and slope position), by...