Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its...
Like most ecological communities, aspen (Populus tremuloides) forests are influenced by a synergy of bottom-up (resources-driven) and top-down (predator-driven) processes. Since the 1920s, ecologists have observed the decline of many aspen communities throughout the Intermountain West. The extent and possible drivers of this decline are topics of much recent scientific...
Herein, we posit a link between the ecological extinction of wolves in the American West
and the expansion in distribution, increased abundance, and inflated ecological influence
of coyotes. We investigate the hypothesis that the release of this mesopredator from wolf
suppression across much of the American West is affecting, via...
Recent natural disasters around the world including
both tsunamis and hurricanes, have highlighted the inability
of wood buildings to withstand wave and surge
loading during these extreme events. Little is known
about the interaction between coastal residential light-frame
wood buildings and wave and surge loading because
often little is left...
Wood-plastic composites are generally presumed to be inherently more resistant to moisture uptake than solid wood, but there is little data on the relative rates of moisture uptake in these materials over time. Trex[R] and Strandex[R] deck sections were immersed in water for up to 215 days, then sections were...
This article examines visitor perceptions of voluntary environmental programs (VEPs) at the Mt. Bachelor ski area in Oregon, USA by examining what they know about VEPs, how these programs influence motivations to visit this area currently and in the future, and how place attachment, value orientations, and specialization influence these...
Lidar is currently the most accurate method for remote estimation of forest structure, but it has limited spatial and temporal coverage. Conversely, Landsat data are more widely available, but exhibit a weaker relationship with structure under medium to high leaf area conditions. One potentially valuable means of enhancing the relationship...
Large quantities of smaller diameter materials are available in the overstocked forests of eastern Oregon and Washington, but the costs of removing these materials and the long distances from markets sharply reduce the potential of this resource. Failure to thin these forests will sharply increase the likelihood of catastrophic wildfires....
In a multilevel study to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were planted beneath second-growth Douglas-fir stands that had...
Flux estimates show that upward mixing of the deep-water nitrate pool accounts for more than 85% of the total new nitrogen input to the euphotic zone of Crater Lake. Because measured primary productivity (360 mg C m-2 d-1) is 10–30 times higher than a level supported solely by the input...
Retreating glaciers and the periglacial areas they vacate for organismal colonization produce a harsh environment of extreme radiation, nutrient limitations, and temperature oscillations. They provide a model system for studying mechanisms that drive establishment and early assembly of communities. Here, we synthesize more than twenty years of research at the...
When large carnivores are extirpated from ecosystems that evolved with apex predators, these systems can change at the herbivore and plant trophic levels. Such changes across trophic levels are called cascading effects and they are very important to conservation. Studies on the effects of reintroduced wolves in Yellowstone National Park...
Uses of outdoor natural areas, like National Forests in the United States, have been undergoing change. Some changes, including criminal activities and domestic terrorism, may have quite important impacts to outdoor enthusiasts and managers. Activities include some relatively traditional management challenges, like arson and thefts, and newer challenges, such as...
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both...
The ratio of live crown length to tree height (crown ratio; CR) is often used as an important predictor variable for tree level growth equations, particularly for multi-species and multi-layered stands. Also, CR indicates tree vigour and can be an important habitat variable. Measurement of CR for each tree can...
Both the structure and composition of naturally generated early-seral forests in the Pacific Northwest (PNW) can be profoundly different than that of more developed forest seres, especially in the period after a major disturbance but before conifers re-develop a closed canopy. While it is reasonable to suggest that the unique...
We sought to improve net ecosystem exchange (NEE) estimates for a tall, dense, mature Douglas-Fir forest in the Oregon Coast range characterized by weak flows, systematic wind directional shear, and limited turbulent mixing throughout the diurnal period. We used eddy covariance (EC) observations at two levels and concurrent biological measurements...
The nonexponential phosphorescence decay of a highly folded form of poly-riboadenylic acid (poly rA) with noncovalently bound dye is explained by a novel application of a well-known theory of electronic excitation transfer based on the Förster mechanism. This theory, originally used to describe singlet-singlet energy transfer from donor molecules to...
We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI)...
Large-scale commercial thinning of young forests in the Pacific Northwest is currently promoted on public lands to accelerate the development of late-seral forest structure for the benefit of wildlife species such as northern spotted owls (Strix occidentalis caurina) and their prey, including the northern flying squirrel (Glaucomys sabrinus). Attempts to...