Janet L. Erickson | USGS Science

USGS2004

Influence of forest management on headwater stream amphibians at multiple spatial scales

Background Amphibians are important components of headwater streams in forest ecosystems of the Pacific Northwest (PNW). They comprise the highest vertebrate biomass and density in these systems and are integral to trophic dynamics both as prey and as predators. The most commonly encountered amphibians in PNW headwater streams include the Pacific giant salamander (Dicamptodon tenebrosus), the tailed frog (Ascaphus truei), the southern torrent salamander (Rhyacotriton variegatus), and the Columbia torrent salamander (R. kezeri).

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USGS2003

Response of birds to thinning young Douglas-fir forests

As a result of recent fire history and decades of even-aged forest management, many coniferous forests in western Oregon are composed of young (20-50 yrs), densely stocked Douglas-fir stands. Often these stands are structurally simple - a single canopy layer with one or two overstory tree species - and have a relatively sparse understory. The lack of structural complexity in these stands may limit the availability of key habitat components for several species of vertebrates, including birds. Thinning may increase structural diversity by reducing competition among overstory trees and increasing the amount of sunlight reaching the forest floor, thereby increasing development of understory vegetation. Existing old-growth forests may have developed under lower densities than is typical of contemporary plantations. Thus, thinning also may be a tool for accelerating the development of late-successional forest conditions in some circumstances. In addition to the potential increases in structural and biological diversity, thinning frequently is used to optimize wood fiber production and to generate timber revenue.

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