Treesearch

Since the early 1990s, several studies have been undertaken to determine the planning requirements, productivity, costs, and residual stand damage of harvest operations in thinning treatments designed to promote development of complex forest structure in order to enhance ecological functioning and biological diversity. Th ese studies include the Oregon State Universityled cooperative Coastal Oregon Productivity Enhancement (COPE) project, the Willamette (National Forest) Young Stand Project (WYS), and the Siuslaw (National Forest) Th inning and Underplanting for Diversity (STUDS) project....

Headwater streams and adjacent riparian areas provide reproductive, foraging, and dispersal habitat for many forest-dependent species, especially amphibians. Although previous studies have shown that the composition of aquatic and riparian animal communities is associated with spatial and temporal patterns of stream fl ow, the relationships among stream fl ow, climate, and thinning are not well known. We characterized stream flow conditions associated with 78 headwater reaches in 13 managed forest sites in the Coast Range and western Cascade Range, Oregon, USA, tracked periodically over a...

Th inning of 30- to 70-year-old Douglas-fir (Pseudotsuga menziesii) stands is a common silvicultural activity on federal forest lands in Washington and Oregon west of the Cascade Range crest. Decreases in forest cover lead to alterations of site energy balances resulting in changes to understory and stream channel microclimates. Uncut vegetative buffers are commonly used to mitigate upland harvest eff ects on aquatic and riparian habitats and functions. To create effective buffers, we need to better understand the relationships among thinning treatments, diff erent riparian buff er widths,...

Studies over the past 40 years have established that riparian buff er retention along streams protects against stream temperature increase. Th is protection is neither universal nor complete; some buff ered streams still warm, while other streams’ temperatures remain stable. Oregon Department of Forestry developed riparian rules in the Forest Practices Act (FPA) to protect fishbearing streams from temperature increases, but it did so with acknowledgement that its rules might be insuffi cient. It developed the Riparian and Stream Function project, otherwise known as RipStream, to validate...

Down wood plays many functional roles in aquatic and riparian ecosystems. Simplifi cation of forest structure and low abundance of down wood in stream channels and riparian areas is a common legacy of historical management in headwater forests west of the Cascade Range in the US northwest. Contemporary management practices emphasize the implementation of vegetation buffers adjacent to streams, and on federal lands thinning has become a predominant form of timber harvest. Th e combined effects of thinning and riparian buff er width on the down wood dynamics in stream channels and riparian...

Down wood is associated with the function, structure, and diversity of riparian systems. Considerable knowledge has been generated regarding down wood stocks and dynamics in temperate forests, but there are few studies on effects of silvicultural practices and riparian buffer design on down wood, particularly in headwater streams. We analyzed interactive eff ects of upland thinning and riparian buffer configuration on down wood volumes and decay classes at fi ve managed forest sites in western Oregon. We tested the eff ects of two thinning treatments—an unthinned control and a moderate-dens...

Large woody debris is recognized as an important component of stream geomorphology and stream ecosystem function, and forest-land management is recognized as an important control on the quantity (and size and species distributions) of wood available for recruitment to streams. Much of the wood present in streams comes from adjacent forests, and riparian management practices now refl ect our understanding of the role these forests play in modulating and maintaining stream environments. In steep terrain, slope failures also carry wood (and sediment) to streams from upslope source areas. In...

We describe demographic processes and species interactions that infl uence Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) in small streams that are part of an eff ort designed to evaluate forest harvest impacts in the Trask Watershed, an industrial forest located in northwest Oregon, USA. Spatial variation in recruitment, individual growth, survival, and movement were quantifi ed during summer low fl ows for four years (2007–2010). Th e phenology of recruitment varied substantially among sites and years. Movement during summer was limited, and varied inconsistently among sites....

Resource managers are increasingly required to conduct integrated analyses of aquatic and terrestrial ecosystems before undertaking any activities. Th ere are a number of research studies on the impacts of management actions on these ecosystems, as well as a growing body of knowledge about ecological processes that aff ect them, particularly aquatic ecosystems, which are used to guide the analyses. Additionally, new tools are available to assist in the analyses. These developments have advanced the potential to conduct these analyses. However, there are some critical issues that need to be...

Th inning of forests has been proposed as a means to increase the carbon stores of forests. Th e justifi cation often offered is that thinning increases stand productivity, which in turn leads to higher carbon stores. While thinning of forests clearly increases the growth of residual trees and increases the amount of harvested carbon compared to an unthinned stand, there is little theoretical or empirical basis for believing that this activity increases the average carbon stores of forests. By removing trees, leaf area is temporarily decreased and carbon input to the forest via photosynthes...