Treesearch

Ectomycorrhizal fungi (EMF) consist of about 5,000 species and profoundly affect forest ecosystems by mediating nutrient and water uptake, protecting roots from pathogens and environmental extremes, and maintaining soil structure and forest food webs. Diversity of EMF likely aids forest ecosystem resilience in the face of changing environmental factors such as pollution and global climate change. Many EMF are increasing in commercial value and gathered both as edible fruiting bodies and for production of metabolites in an emerging biotechnical industry. Concerns over decline of EMF have...

Wind disturbance plays a fundamental role in shaping forest dynamics in southeast Alaska. Recent studies have increased our appreciation for the effects of wind at both large and small scales. Current thinking is that wind disturbance characteristics change over a continuum dependent on landscape features (e.g., exposure, landscape position, topography). Data modeling has revealed the existence of distinct wind disturbance regimes, grading from exposed landscapes where recurrent, large-scale wind events prevail to wind-protected landscapes where small-scale canopy gaps predominate....

Two measures of stumpage prices and timber volumes from individual National Forests have been compiled for the Pacific Northwest Region, USDA Forest Service. The first measure is the price and volume of timber sold (1984-96) for the major species for each National Forest. The second measure is the price and volume of timber harvested (1988-96) from individual National Forests. Several price-related issues are discussed including seasonality in the data, the role of prices in monitoring market activity, and the impact of the recent drop in Forest Service timber sales.

Characteristics of an outbreak of the Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough)) in 1991-95 on the Burns Ranger District of the Malheur National Forest (eastern Oregon) are given and compared with an earlier infestation in the same area in 1963-65. Results of monitoring with pheromone traps, evaluating populations by sampling larvae, and predicting trends and defoliation are reported in detail for the latest outbreak. Temporal patterns of each outbreak also are described and compared with the classic behavior of other tussock moth outbreaks. Findings of this analysis, and...

The impact of increasing the number of crosses per parent (k) on the efficiency of roguing seed orchards (backwards selection, i.e., reselection of parents) was examined by using Monte Carlo simulation. Efficiencies were examined in light of advanced-generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) tree improvement programs where information is available from previous generations, seed orchards have reduced genetic variation as a result of selection, and dominance variation is small compared with additive variation. Both the efficiency of reselection and its associated...

Forest carnivores in the Pacific Northwest include 11 medium to large-sized mammalian species of canids, felids, mustelids, and ursids. These carnivores have widely differing status in the region, with some harvested in regulated furbearer seasons, some taken for depredations, and some protected because of rarity. Most large carnivores have declined in numbers or range from human encroachment, loss or modification of forest habitat, accidental deaths (e.g., mortality from vehicles), illegal kills, and our inability to adequately monitor and protect populations. Efforts to reverse these...

Spawning Pacific salmon (Onchorhynchus) transport marine-derived nutrients into streams and rivers. Subsequently, these marine-derived nutrients are incorporated into freshwater and terrestrial food webs through decomposition and predation. In this study, we investigated the influence of spawning Pacific salmon on terrestrial vegetation using stable isotope analysis. We hypothesized that terrestrial vegetation near streams or in areas with activity of piscivorous predators will show higher δ15SN values compared with the same species growing elsewhere. The influence of spawning Pacific...

A natural decline in the population of yellow-cedar (Chamaecyparis nootkatensis) is occurring in pristine southeast Alaska forests and may be the most significant forest decline in the western United States. The frequency of landslides in cedar decline areas is three times larger than in areas of healthy forest. Three regions are investigated in order to determine the influence of yellowcedar decline on root strength, soil saturation, and consequently, slope stability. Nearly complete deterioration is observed in roots up to 25 mm thick on cedar trees that have been dead for approximately...

Provides current information on lumber and plywood production and prices; employment in the forest industries: international trade in logs, lumber, and plywood; volume and average prices of stumpage sold by public agencies: and other related items.

Provides current information on lumber and plywood production and prices; employment in the forest industries: international trade in logs, lumber, and plywood; volume and average prices of stumpage sold by public agencies: and other related items.