Treesearch

The May 18, 1980, eruption of Mount St. Helens in Washington is possibly the best documented geological event in history. The bibliography displays the results of 13 years of biological and related research in a convenient, indexed format. Our intent is to facilitate collaboration between scientists contemplating new research initiatives and experienced investigators who have conducted baseline studies at the volcano. Prospective investigators are encouraged to contact the Monument Scientist and individual authors listed in the research abstracts to find out more about research opportunitie...

BIOPAK is a menu-driven package of computer programs for IBM-compatible personal computers that calculates the biomass, area, height, length, or volume of plant components (leaves, branches, stem, crown, and roots). The routines were written in FoxPro, Fortran, and C. BIOPAK was created to facilitate linking of a diverse array of vegetation datasets with the appropriate subset of available equations for estimating plant components, such as biomass and leaf area. BIOPAK produces reports that are formatted for people and files that are compatible with other software. Other reports document...

More than 100 species of vertebrates in the Pacific Northwest use standing dead trees (snags) at one time or another in their lifecycle (Thomas et al. 1979a, Neitro et al. 1985). With few exceptions, investigators have found significant correlations between snag density and the abundance of primary cavity-nesters in North American coniferous forests (Raphael and White 1984:47-53, Madsen 1985, Zarnowitz and Manuwal 1985, McComb et al. 1986, Land et al. 1989, Carey et al. 1991, Schreiber and deCalesta 1992). Similar relationships have been detected for secondary cavity-nesters (Schreiber and...

Results of the Iron Creek installation of the levels-of-growing-stock study in Douglasfir (Pseudotsuga menziesii (Mirb.) Franco) are summarized. To age 42 (planned completion of the experiment) volume growth in this site II Douglas-fir plantation has been strongly related to level of growing stock, partially offsetting the decrease in volume growth percent expected with increasing growing stock. Basal area growth-growing stock relations were much weaker than those for volume. Marked differences in tree size distributions have resulted from thinning. Periodic annual volume increments are...

This paper examines by climax conifer series, historical and current roles of many important pathogens and insects of interior Northwest coniferous forests, and their unique responses to changing successional conditions resulting from management. Insects and pathogens of the subalpine fir and mountain hemlock series historically reduced inter-tree competition for site resources, and generated most of the coarse woody debris between fires. Severity of growth and mortality effects was proportional to the abundance of susceptible seral species such as Douglas-fir, grand fir, and lodgepole...

We analyzed historical and current vegetation composition and structure in 49 sample watersheds, primarily on National Forests, within six river basins in eastern Oregon and Washington. Vegetation patterns were mapped from aerial photographs taken from 1932 to 1959, and from 1985 to 1992. We described vegetation attributes, landscape patterns, the range of historical variability, scales of change, and disturbance hazards. Forest cover increased eight percent in three river basins, but remained relatively unchanged in the other basins. Forests became more dense in vertical and horizontal...

Fire has been an important ecological process in eastside Cascade ecosystems for millennia. Fire regimes ranged from low severity to high severity, and historic fire return intervals ranged from less than a decade to greater than 300 years. Fire history and effects are described for grassland and shrubland ecosystems, and the range of forested communities by plant series: Ponderosa Pine, Douglas-fir/White fir/Grand fir, Lodgepole pine, Western hemlock/Western redcedar, and subalpine fir/Mountain hemlock. The riparian zones within these communities may be more or less impacted by fire. The...

Existing literature was used to estimate the economic value of elk to hunters and wildlife watchers, and the economic impact on personal income to local communities in the Blue Mountains (Blues) of Oregon and Washington. An annual survey of hunters at the Starkey Experimental Forest and Range provided data for estimated elk hunting values and expenditure impacts. The Starkey data show an estimated median value of about $118 per trip in 1991 dollars; assumptions allowing a mean per-day value, over and above expenditures, result in a potential range of $39 to $78. A previous literature...

A retrospective examination of the history of the cumulative influences of past land and water uses on the ecological health of select river basins in forest regions of eastern Washington and Oregon indicates the loss of fish and riparian habitat diversity and quality since the 19th century. A physiographic framework of the eastern Washington and Oregon in terms of spatial and temporal geologic, climatic and hydrologic conditions provides a regional perspective for reviewing influences of human patterns of settlement, resource development and management on the river basins. The study...

Investigators have historically measured soil CO2 efflux as an indicator of soil microbial and root activity and more recently in calculations of carbon budgets. The most common methods estimate CO2 efflux by placing a chamber over the soil surface and quantifying the amount of CO2 entering the chamber per unit area of soil per unit time. Schlesinger (1977), Anderson (1982), Rolston (1986a), Raich and Nadelhoffer (1989), and Nakayama (1990) have reviewed various chamber methods. No single method is established as a standard (Anderson 1982, Nakayama 1990, Norman et al. 1992), partly because...