Treesearch

Leafy spurge is an invasive weed that has appeared along streams throughout much of the country. Riparian ecosystems are particularly sensitive areas that can be threatened by nonnative invasive species. These areas also can be damaged by herbicides commonly used in uplands to control invasive plants. In a collaborative effort by the U.S. Forest Service, Bureau of Land Management, and Agricultural Research Service, researchers found an effective way to use an insect to control the weed. Flea beetles (Aphthona spp.) are a natural predator of leafy spurge in its native range in Europe and...

People have long valued mature western redcedar for its strong, lightweight wood that is rot-resistant.The species has cultural importance for Northwest tribes who use the tree’s bark and roots as well as the wood. Redcedar is very shade-tolerant and is often found in the understory and midstory of Pacific Northwest forests. It is also very adaptable and can grow on a wide range of site conditions in both single- and mixed-species stands. In contrast to Douglas-fir, the subject of countless studies related to its growth potential and response to management in the region, very little has...

National forest managers are charged with tackling the effects of climate change on the natural resources under their care. The Forest Service National Roadmap for Responding to Climate Change and the Climate Change Performance Scorecard require managers to make significant progress in addressing climate change by 2015. To help land managers meet this challenge, Forest Service scientists conducted three case studies on national forests and adjacent national parks and documented a wide range of scientific issues and solutions. They summarized the scientific foundation for climate change...

Exploring relationships between landscape characteristics and rivers is an emerging field, enabled by the proliferation of satellite date, advances in statistical analysis, and increased emphasis on large-scale monitoring. Landscapes features such as road networks, underlying geology, and human developments, determine the characteristics of the rivers flowing through them. A multi-agency team of scientists developed novel modeling methods to link these landscape features to in-steam habitat and abundance of coho salmon in Oregon coastal streams. This is the first comprehensive analysis of...

Mule deer populations in central Oregon are in decline, largely because of habitat loss. Several factors are likely contributors. Encroaching juniper and invasive cheatgrass are replacing deer forage with high nutritional value, such as bitterbrush and sagebrush. Fire suppression and reduced timber harvests mean fewer acres of early successional forest, which also offer forage opportunities. Human development, including homes and roads, is another factor. It is this one that scientists with the Pacific Northwest Research Station and their collaborators investigated in a recent study. As...

Scientists have had little information about how prescribed fire and cattle grazing—common practices in many Western ponderosa pine forests—affects plant abundance and reproduction in the forest understory. Pacific Northwest Research Station scientists began to explore how these practices affect vegetation in a five-year study of postfire vegetation in eastern Oregon ponderosa pine forests where cattle have been routinely pastured from late June or early July through early to mid August. For this area of eastern Oregon, they found that excluding cattle grazing during peak growing season...

Populations of greater sage-grouse have declined dramatically across their North American range for many decades in response to harmful effects of a plethora of human activities and land uses, prompting legal actions to protect the species under the Endangered Species Act (ESA). To evaluate the impacts of land-uses and habitat changes on sage-grouse, Michael Wisdom, a research wildlife biologist, and his colleagues used novel landscape modeling methods to carry out a comprehensive, range-wide analysis that considered 22 environmental factors in areas currently inhabited by sage-grouse...

We analyzed wildfire exposure for key social and ecological features on the national forests in Oregon and Washington. The forests contain numerous urban interfaces, old growth forests, recreational sites, and habitat for rare and endangered species. Many of these resources are threatened by wildfire, especially in the east Cascade Mountains fire-prone forests. The study illustrates the application of wildfire simulation for risk assessment where the major threat is from large and rare naturally ignited fires, versus many previous studies that have focused on risk driven by frequent and...

Using lidar in an area-based model-assisted approach to forest inventory has the potential to increase estimation precision for some forest inventory variables. This study documents the bias and precision of a model-assisted (regression estimation) approach to forest inventory with lidar-derived auxiliary variables relative to lidar pulse density and the number of sample plots. For managed forests on the Lewis portion of the Lewis-McChord Joint Base (35 025 ha, 23 290 forested) in western Washington state, we evaluated a regression estimator for combinations of pulse density (.05–3...

The paper summarizes over 40 years of research on the downstream geomorphic responses of rivers to dams, with a particular emphasis on gravel-bed rivers, and evaluates the state if the science with respect to predicting channel adjustments: channel incision, lateral adjustments, and bed textural changes. Effects of vegetation and implications for management are also addressed.