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...
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...
This study had three objectives: (1) to teat the hypothesis that multiple flushing of the terminal shoot (intermittent growth pattern) in Douglas-fir seedlings (Pseudotsuca menziesii var. menziesii) has an adaptive significance, especially in inland populations from the drier regions in southwest Oregon; (2) to evaluate the genetic and adaptive consequences...
The effect of defoliation intensity and season on Douglas-fir growth
were studied in three replications in the Siuslaw National Forest during
1988-1990. Four intensities of defoliation were applied once in either spring or
summer 1988. Stem diameter and canopy area were linearly inversely
proportional to the level of defoliation. Defoliation...
Diameter growth of Douglas-fir (Pseudotsuqa menziesii (Mirb.) Franco) estimated from increment cores was compared with that obtained from repeated measurements of tree diameter on permanent plots located in two Douglas-fir study areas in the central Coast Range of Oregon. Growth was measured for a 6-year period (1979-
1985). Diameter growth...
The Levels-of-Growing-Stock Studies in Douglas-fir is a regional cooperative to investigate the effects of levels of growing stock on young stand growth. The Hoskins
installation, in western Oregon, was established in a dense, high site natural stand at total age 20 years. The initial thinning resulted in an immediate 131...
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...
The objectives of this research were to study: a) the effect of thinning and treatments consisting of pruning
and multinutrient fertilization on aboveground biolnass increment, growth efficiency (GE), and foliar nutrients;
b) the influence of topoedaphic variables (soil nutrients, slope, aspect, and rock content) and foliar nutrients on both leaf...
The response to various levels of stand density by natural Douglas-fir regeneration, shrub and sprouting hardwood species was studied in the mixed-evergreen-forests of southwest Oregon. Partial-cut old growth (harvested 22-31 years prior) and thinned evenaged (harvested 9-17 years prior) stand types were used as surrogates for intentionally managed uneven-aged stand...
Growth was assessed for Douglasfir reproduction which had established naturally beneath three intensities of overstory thinning in a 65-year-old stand of Douglas-fir on the east side of the Oregon Coast Range. The age of advanced reproduction ranged from 4 to 15 years. Understory environments were described in terms of sunlight,...