Molybdenum is an essential component of biogeochemical cycling, most notably as a component of the nitrogenase enzyme used in biological nitrogen (N) fixation. While the important role of phosphorus (P) in limiting N fixation in ecosystems has been well documented, occurrence and prevalence of molybdenum (Mo) limitation is largely unknown....
Ecosystem nitrogen (N) supply strongly influences the availability and cycling of other essential nutrients in temperate forests, especially calcium (Ca). Short-term additions of N that exceed ecosystem demands often increase dissolved nitrate fluxes and decrease soil pH, which can stimulate soil Ca loss. However, the long-term effects of high N...
Understanding the tradeoff between water use and productivity is critical for modeling growth of intensively managed Douglas-fir forests in the Pacific Northwest. Evapotranspiration is closely linked to carbon dioxide intake during the process of photosynthesis. However, summer drought characterizing the growing season in this region imposes a limit on carbon...
One of the goals of ecosystem management is to integrate management of many species and processes across a range of temporal and spatial scales. I investigated the relationship between small mammals and amphibians at 3 spatial scales. My objective
was to identify, habitat associations of forest floor vertebrates at the...
Human-induced fragmentation of forests is increasing, yet the consequences of these landscape changes to vertebrate communities are poorly understood. Despite progress in our understanding of how bird communities
respond to forest fragmentation caused by agricultural or urban development, we have little understanding of these dynamics in landscapes undergoing intensive forest...
Western hemlock forests in the coastal areas of Oregon are some of the most productive and diverse forests in the world. This rich diversity represents both a challenge and an opportunity for woodland owners interested in managing western hemlock on their property.
In western Oregon, hardwood trees occupy 20% of the
timberland but account for less than 1% of the timber
harvest. Information about how to manage them effectively
is limited.
The objective of this study was to examine: 1)
effect of thinning on tree growth, plant moisture stress,
and crown cover...
The work upon which this publication is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964 and by the United States Department of Agriculture, Forest Service, Pacific Northwest Forest...
Channels that were scoured to bedrock by debris flows provided unique opportunities to calculate the rate of sediment and wood accumulation, to make inferences about processes associated with input and transport of sediment, and to gain insight into the temporal succession of channel morphology following disturbance. In an intensive investigation...
Improving vegetation management decisions in Pacific Northwest forests requires a better understanding of the interactions between
planted conifers and associated vegetation. A practical index of interspecific competition, and quantitative models predicting conifer performance from such an index are particularly needed. To meet this
need, neighborhood models of interspecific competition were...