Treesearch

Common and scientific names.

The Integrated Landscape Assessment Project (ILAP) was a multiyear effort to produce information, maps, and models to help land managers, policymakers, and others conduct mid- to broad-scale (e.g., watersheds to states and larger areas) prioritization of land management actions, perform landscape assessments, and estimate cumulative effects of management actions for planning and other purposes. The ILAP provided complete cross-ownership geospatial data and maps on current vegetation, potential vegetation, land ownership and management allocation classes, and other landscape attributes...

Fire suppression, vegetation management activities, wildfires, grazing, climate change, and other factors result in constantly changing vegetation and habitat conditions across millions of hectares in the Western United States. In recent years, the size and number of large wildfires has grown, threatening lives, property, and ecosystem integrity. At the same time, habitat for species of concern is often becoming less suitable, the economic vitality of many natural resource-dependent human communities is declining, and resources available for land management are limited. Techniques are...

Swiss needle cast is caused by a fungus native to the Pacific Northwest. Its host is Douglas-fir, an iconic evergreen tree in the region. The fungus does not kill its host, but it adversely affects the tree's growth. The fungal fruiting bodies block the stomata, small openings on the underside of the needle where carbon dioxide, water vapor, and other gases are exchanged. As more stomata become blocked, there is a corresponding reduction in photosynthesis this means the tree produces less carbohydrates necessary for growth. Scientists with the Pacific Northwest Research Station and their...

Nitrogen is an element essential to plant growth and ecosystem productivity. Excess nitrogen, however, is a common water pollutant. It can lead to algal blooms that deplete the water's dissolved oxygen, creating "dead zones" devoid of fish and aquatic insects. Previous research showed that the subsurface area of a stream, known as the hyporheic zone, regulated amounts of waterborne nitrogen, but the nature of that role was unclear. Forest Service and university scientists undertook a suite of experiments to learn what factors determine if the hyporheic zone will be source or a sink for...

Composition of diets selected by tame but free-ranging deer in a natural forest environment was studied throughout a 24-month period and summarized by mean monthly percentage composition on the basis of dry-matter intake. A modifi cation of the standard bite-count method of diet determination was used. All forages were identifi ed by species and plant part (leaf, twig). Major forages comprising the diet were identifi ed seasonally and considered in relation to their role in the nutritional ecology of the deer. Overall, a simple but consistent pattern was evident in the data. When green,...

Variation in nutritional quality of natural forages for black-tailed deer (Odocoileus hemionus) was studied in summer and winter in southeast Alaska. Freeze-dried samples of 17 summer forages collected in early July and 10 winter forages collected in February from three replicate sites each of shady forest understory and open, sunny habitat were analyzed and compared for their concentrations of digestible protein, digestible dry matter, and digestible energy. Data from each forage, ranging from forb and shrub leaves to woody twigs, were analyzed separately in a single-factor analysis of...

The contribution of understorey vegetation (UVEG) to forest ecosystem biomass and carbon (C) across diverse forest types has, to date, eluded quantification at regional and national scales. Efforts to quantify UVEG C have been limited to field-intensive studies or broad-scalemodelling approaches lacking fieldmeasurements. Although large-scale inventories of UVEG C are not common, species- and community-level inventories of vegetation structure are available and may prove useful in quantifying UVEG C stocks. This analysis developed a general framework for estimating UVEG C stocks by...

This paper develops a plot-level spatial econometric land-use model and estimates it with U.S. Geological Survey Land Cover Trends (LCT) geographic information system panel data for the western halves of the states of Oregon and Washington. The discrete-choice framework we use models plot-scale choices of the three dominant land uses in this region: forest, agriculture, and urban development. The results provide a technical foundation for developing larger scale models from the LCT database. In particular, we develop a random-effects estimation method for dealing with the spatially...

We evaluated the effect of forest riparian alternative tree buffer designs on Western Red-backed Salamanders (Plethodon vehiculum) along headwater stream banks in managed forests of the Washington Coast Range. We used pit trap live removals in early autumn to estimate relative abundances of surface-active salamanders before and after 3 levels of riparian buffer retention (strip, patch, and no-buffer clear-cut) with upland regeneration harvest. The study spanned a pre-treatment year, the harvest year after logging, and 2 post-treatment years (post1, post2). We observed reduced average tree...