Treesearch

Nonnative invasive insects are having major impacts on the economics and ecology of forests nationwide. Until recently, Alaska was fortunately mostly free of these pests. Because of the remoteness of much of Alaska's native forests, an invasive pest infestation would be extremely difficult to control. Global markets, global climate change, and the ever-increasing mobility of people, goods, and services are working in concert to increase the risk of invasion by exotic organisms to Alaska forests to unprecedented levels.

Late summer streamflow in western and central Oregon and northern California is almost exclusively due to immense groundwater storage in the Cascade Range. The volume of water stored in permeable lava flows in the Cascades is seven times that stored as snow. Nonetheless, until recently, virtually all examinations of streamflow trends under future climates in the West have focused on the anticipated loss of snowpack. This has painted an incomplete picture of the looming water resource crisis that is expected because of global warming.

For more than a century, yellow-cedar has been inexplicably dying throughout the northern coastal rain forests of the Pacific Northwest. Yellow-cedar mortality has been mapped on more than a half million acres in southeastern Alaska, yet until recently the cause of death was a stubborn mystery. Researchers are hopeful, after several decades of investigation, that they have finally exposed the cause of yellow-cedar decline.

In response to societal concerns about clearcutting in the Pacific Northwest, structural or green-tree retention is now an integral part of harvest prescriptions on federal lands. However, the benefits of different levels or patterns of retention for the ecological, microclimatic, and aesthetic attributes of resulting forest stands remain speculative.

Sagebrush habitats are declining rapidly across western North America, with over 350 associated plant and animal species at risk of local or regional extirpation. The sagebrush ecosystem is one of the largest in the United States, and it is vulnerable to a litany of threats. Chief among them is invasion of cheatgrass into the understory, followed by high-severity fires that cheatgrass promotes. The expansion of pinyon juniper woodlands into sagebrush habitat and other human impacts, such as overgrazing by livestock and energy development, are also major sources of concern.

The marbled murrelet is a small diving seabird that occupies coastal waters from Alaska to central California. Murrelets have a unique nesting strategy that requires them to commute tens of miles inland, where they use large mossy branches on older conifers as platforms to balance their solitary egg. Populations have been declining for decades as the amount of nesting habitat has been reduced through logging. The murrelet was listed under the Endangered Species Act in 1992. Two years later, Pacific Northwest federal forests were brought under the management of the Northwest Forest Plan,...

Oregon white oak savanna and woodland habitat in the Pacific Northwest has declined to less than 10 percent of its former range, and much of what remains is of poor quality. In addition to urbanization and agricultural development, habitat is being lost to conifers that have invaded oak areas, which were once maintained through frequent burning by Native Americans. The conifers eventually overtop and kill the shade-intolerant oaks. Many landowners, conservation groups, and public agencies are interested in restoring the cultural legacy and biodiversity associated with oak habitat. Until...

The Northwest Forest Plan (the Plan) was designed to balance protection of older forest ecosystems with mitigation of impacts on rural communities and economies. It was implemented by using an adaptive management approach that featured an interagency monitoring program. This program included socioeconomic monitoring—the systematic observation and measurement of a set of social and economic indicators over time—to evaluate the effects of the Plan on forest communities. Socioeconomic goals of the Plan included producing predictable levels of timber and nontimber resources, maintaining the...

Mountain meadows in the Pacific Northwest are patches of remarkable biological diversity. Lush, forb-, grass-, and shrub-dominated communities attract rich assemblages of arthropods, support diverse communities of birds, and provide habitat for small mammals and other wildlife. Recent encroachment by conifers has reduced the extent and ecological integrity of meadows, with consequences for their biota, scenic values, and recreational use. Using a diversity of approaches, researchers and managers are attempting to unravel the causes and consequences of encroachment and the potential for...

Nitrogen (N) pollution is a growing concern in forests of the greater Sierra Nevada, which lie downwind of the highly populated and agricultural Central Valley. Nitrogen content of Letharia vulpina tissue was analyzed from 38 sites using total Kjeldahl analysis to provide a preliminary assessment of N deposition patterns. Collections were co-located with plots where epiphytic macrolichen communities are used for estimating ammonia (NH3) deposition. Tissue N ranged from 0.6% to 2.11% with the highest values occurring in the southwestern Sierra Nevada (range: 1.38 to 2.11). Tissue N at 17...