Forest management requires classification of forest stands into groupings or types based on structural similarities, even when structure varies continuously along gradients. Managed, mixed-species, multi-aged forest stands often display complex structures containing extreme variation in trees size, density, and species composition, and as a result have diverse canopy structures. A...
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...
This paper was published in: Deal, R.L. and C.A. Harrington, eds. 2006. Red alder—a state of knowledge. General Technical Report PNW-GTR-669. Portland, OR: U.S. Department of Agriculture, Pacific Northwest Research Station. 150 p.
It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly...
Extractives can account for between 1 to 20% of the oven-dry weight of wood of various tree species and can influence wood density values appreciably. Removing these chemical deposits (extraction)in wood samples can help establish a consistent baseline for comparing wood densities where extractives are expected to differ between sample...
Cross-sectional disks were cut at two stem heights (1.5 m and 3.0 m) from 9-year-old trees of three Populus clones grown in an intensively-cultured plantation in western Washington. At age 1.5 years, when the trees averaged 3.4 m tall, half of the trees were pruned by removing all branches below...
Biotic and abiotic processes at continent-ocean interfaces cycle a disproportionate mass of carbon and nutrients relative to their global surface area, and microbial activity is a principal determinant of organic and inorganic matter flux in these transition zones. Most studies using modern high-throughput ‘omics techniques to link microorganisms with costal...
Following European-American colonization of North America and associated landscape changes, barred owls (Strix varia) underwent a dramatic expansion of their historical range. The barred owl expanded across the previously tree-less Great Plains that had limited their distribution, and into the forests along the west coast. In these western forests they...
The modern world has presented many threats to the health and stability of ecosystems worldwide. One of the most biodiverse ecosystems, coral reefs, faces particularly strong pressures, and is already declining rapidly in complexity and area. Although the stressors that affect reefs are diverse, ranging from nutrient pollution to overfishing,...
Soil nitrogen exists largely as organic matter, including plant liter, dead animal matter, and microbial necromass. About 90% of soil organic nitrogen is proteinaceous material that is too large for plants and microorganisms to assimilate directly. Protein depolymerization therefore plays a critical role in mobilizing this organic source of nitrogen,...
