Effects of small-scale disturbances on fecundity and growth rates of Linnaea
borealis L., Tiarella trifoliata L. var. unifoliata, and Trillium ovatum Pursh. were studied in
old-growth forests in the Tsuga heterophylla Zone on the west slope of the Cascade
Mountain Range of Oregon. Performance of each species was compared in...
This study assessed the effects of thinning on arthropod communities on understory plants in the Central Oregon Coast Range. Arthropods were sampled from five understory plants in five pairs of thinned and unthinned, young (50-80 yrs), managed Douglas-fir stands, from late May to mid-July of 1998. Vine maple (Acer circinatum),...
A simple debris-slide model, employing a digital elevation model (DEM) and geological data, was used in a geographic information system (GIS) to map slope stability in the Andrews Experimental Forest, located in the western Cascade Range in Oregon, USA. To evaluate the contribution of error in elevation to the uncertainty...
The growth potential of Douglas-fir, grand fir and western hemlock advance regeneration in the forest understory of Douglas-fir-dominated forests was investigated to detennine the feasibility of selection cutting systems in northwest Oregon. This study compared the growth of Douglas-fir, grand fir and western hemlock advance regeneration along a light gradient...
Seasonal and annual patterns of N fluxes and concentrations in streamwater in six conifer-dominated watersheds at the H.J. Andrews Experimental Forest, OR, were studied to gain insight into the factors that influence N retention in this ecosystem. Processes affecting N flux in streamwater differed between organic (DON) and inorganic (DIN;...
Viability analysis of well-selected focal species can complement other types of conservation planning by revealing thresholds in habitat area and landscape connectivity that may not be evident from ecosystem-level evaluations. I used focal species analysis of five carnivores to suggest conservation planning guidelines for the Rocky Mountains and adjacent areas...
A series of studies, in three western Oregon Douglas-fir plantations, was conducted to understand the physiological impacts of Swiss needle cast on Douglas-fir physiology. Four aspects of the disease complex were investigated: fungal colonization and assessment, plant-water relations, carbon assimilation and interaction with climate. Several techniques were developed and used...
My objectives were to investigate the correlation of height and diameter growth in young Douglas-fir (Pseudotsuga menziesii) plantations with stand density, and to determine the effects of stand density on the canopy boundary layer conductance (g[subscript]ac) and microclimate characteristics of young Douglas-fir plantations. I measured annual height (h) and diameter...
This study examined debris flows occurring in a 125 km² study area in the Blue River watershed in the western Cascade Mountains of Oregon over a 50-year period. Debris flow occurrence was found to be concentrated in a distinct zone of high activity occupying approximately half of the study area,...
These studies are part of the Demonstration of Ecosystem Management Options (DEMO) study, a program researching the effects of different levels and patterns of green-tree retention on ecological, economic, and social phenomena. We restricted our studies to the 15% basal area, evenly dispersed retention treatment. Our objectives were, first, to...