Treesearch

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...

Th inning has been increasingly used in the Pacifi c Northwest to restore structural and biological diversity to densely-stocked young- to mid-aged forests that have been previously intensively managed for timber production. In the short term, thinning promotes development of understory vegetation, which in turn can increase habitat diversity for wildlife, particularly for songbirds. Thinning also has been identifi ed as a potential approach to accelerate the development of characteristics that are typical of older forest stands. Both the immediate and long-term response of wildlife and...

Forest thinning has been widely used in the Pacifi c Northwest as a technique to accelerate latesuccessional vegetation characteristics and promote mature forest habitats for wildlife. Th inning treatments aff ect tree and understory vegetation development. Th e eff ects of thinning on bird abundance and occurrence vary by bird species and change over time, presumably as a result of changes in understory and overstory vegetation after thinning. However, this assumption has rarely been tested. Vegetation characteristics, such as canopy cover, understory density and composition are frequently...

Epiphytic lichen communities have become a focus for ecologists concerned with forest health because lichens are particularly responsive to forest management and air quality. Furthermore, they can contribute substantially to the diversity and nitrogen fi xation of a stand, and play a valuable role in the food web of many forest-dwelling organisms. Can strategic thinning in Pseudotsuga -Tsuga forests increase biodiversity or hasten the development of late-successional features in young second-growth forests? Approximately 10 years after variable-density commercial thinning, N fixing and...

Th e Demonstration of Ecosystem Management Options (DEMO) project is a large, interdisciplinary study designed to test the biological and silvicultural eff ects of green-tree retention in Douglas-fi r (Pseudotsuga menziesii) forests. Six treatments were replicated on six blocks in Washington and Oregon, USA: no harvest, 75 percent aggregated, 40 percent (dispersed and aggregated), and 15 percent (dispersed and aggregated) green-tree retention. We studied treatment eff ects on ectomycorrhizal fungi in three of the study blocks. Ectomycorrhizae (EM) were sampled by use of soil cores. Prior...

Commercial matsutake mushroom (Tricholoma magnivelare) harvest in the Pacific Northwest is common in Lodgepole Pine (Pinus contorta) forests. Insuffi cient ecological knowledge of the mycorrhizae and mycelium has challenged monitoring of this resource. Among many management issues are concerns over logging practices, a lack of information on the ecology and habitat requirements of American Matsutake, and the potential eff ects of the type and intensity of matsutake harvest on future mushroom productivity. Lodgepole Pine and mixed-conifer stands provide habitat for growing and harvesting...

Increasing global demands on forest resources are driving large-scale shifts toward plantation forestry. Simultaneously balancing resource extraction and ecological sustainability objectives in plantation forests requires the incorporation of innovative silvicultural strategies such as leave islands (green-tree retention clusters). Our primary research goal was to determine how leave islands provide refugia for low-mobility, ecologically sensitive species in managed forests of the Pacifi c Northwest, USA. We examined patterns in vascular plant, arthropod, amphibian, and mollusk assemblages...

In recent years, forest management in the Pacifi c Northwest has shifted from one based largely on resource extraction to one based on ecosystem management principles. Forest management based on these principles involves simultaneously balancing and sustaining multiple forest resource values, including silvicultural, social, economic, and ecological objectives. Leave islands, or green-tree retention clusters, have been proposed as an alternative silvicultural strategy designed to sustain the ecological integrity and biological diversity within intensively managed forests. However, pertinent...

Presentation Abstract Old-growth Douglas-fi r (Pseudotsuga menziesii) forests are a goal for conservation and restoration across millions of acres of federal forest lands in western Oregon and Washington. Where old growth currently exists, management is typically focused on protecting stands and watersheds from logging and high-severity wildfi re. Where old growth was converted to Douglas-fi r plantations during the 20th century, the goal is often to actively manage those areas to create ecological diversity and accelerate development of old-growth conditions. What does it mean to use old...

Th inning stands (managing their densities) aff ects the development of trees and understory plants as individuals, as well as stand-level characteristics like structure, microclimate, and stand growth, habitat for various species, and fuel and potential fi re severity. Th ese characteristics and the rate of changes are aff ected by thinning severity—the reduction in numbers of trees, the stand density, and also by the number, sizes, species, and growth rates of the trees retained. In addition, site variables like potential for severe wind and ice/snow storms, soil depth/rooting, root...