Treesearch

Human modification of forest habitats is a major component of global environmental change. Even areas that remain predominantly forested may be changed considerably by human alteration of historical disturbance regimes. To better understand human influences on the abundance and pattern of forest habitats, we studied forest land cover change from 1936 to 1996 in a 25 000 km2 landscape in the Oregon (USA) Coast Range. We integrated historical forest survey data and maps from 1936 with satellite imagery and GIS data from 1996 to quantify changes in major forest cover types. Change in the...

Although the Tongass National Forest (TNF) possesses abundant stands of redcedar (Thuja plicata Donn), yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach), Sitka spruce (Picea sitchensis (Bong.) Carr.), and western hemlock (Tsuga heterophylla (Raf.) Sarg), most of its buildings, bridges, and trails are constructed from imported materials. The costs incurred in importing lumber building materials to the TNF seemingly could be offset by manufacturing a slightly more costly product from within the region. To better understand the potential opportunities foregone by southeast Alaska’s...

The link between forest management and the well-being of communities in forested areas has traditionally been defined by forest sector employment opportunities. Attempts to redefine this relationship have produced methods that use a more comprehensive approach by combining both economic and social indicators to evaluate community well-being. The goal of this study is to evaluate socioeconomic resilience and forest dependence in Washington counties in order to identify counties where changes in forest management could negatively affect the well-being of nearby residents, allowing land...

The Forest Inventory and Analysis Program of the Pacific Northwest Research Station collected, analyzed, and summarized data from field plots, and mapped land cover on four islands in American Samoa. This statistical sample provides estimates of forest area, stem volume, biomass, numbers of trees, damages to trees, and tree size distribution. The summary provides detailed tables and graphical highlights to help inform resource managers and policymakers, as well as educating the public regarding the status and trends in their natural resources.

Field trials at six bare-root forest tree nurseries in the Western United States compared cultural treatments including timing and depth of sowing; bare fallow (with and without periodic tilling); organic amendments including sawdust, composts, and cover crops; mulches including pine needles, sawdust, and rice straw; and fumigation with methyl bromide/chloropicrin or dazomet. Measured effects included population levels of potential soil-borne pathogens (species of Fusarium and Pythium), disease incidence, seedbed density, and sizes of conifer seedlings. Several nonfumigation treatments...

A network of 32 drought sensitive tree-ring chronologies is used to reconstruct mean water year flow on the Columbia River at The Dalles, Oregon, since 1750. The reconstruction explains 30 percent of the variability in mean water year (October to September) flow, with a large portion of unexplained variance caused by underestimates of the most severe low flow events. Residual statistics from the tree-ring reconstruction, as well as an identically specified instrumental reconstruction, exhibit positive trends over time. This finding suggests that the relationship between drought and...

Forested habitats for cattle and elk (Cervus elaphus) in the western United States have changed substantially in response to intensive timber management during the latter half of the 20th century. Consequently, the subject of how elk and other ungulates respond to timber management is a high-profile, long-standing issue that continues to be studied and debated (Lyon and Christensen 2002). The need for additional knowledge about effects of timber management on cattle and elk remains high, given the fact that timber management continues to affect nearly all cattle and elk ranges on national...

Forest inventories and remote sensing are the two principal data sources used to estimate carbon (C) stocks and fluxes for large forest regions. National governments have historically relied on forest inventories for assessments but developments in remote sensing technology provide additional opportunities for operational C monitoring. The estimate of total C stock in live forest biomass modeled from Landsat imagery for the St. Petersburg region was consistent with estimates derived from forest inventory data for the early 1990s (272 and 269 TgC, respectively). The estimates of mean C sink...

Many assessments of soil C have been restricted to the 2-mm fractions of forest mineral soils. Our objective was to determine the importance of the >2mm fraction to whole-soil C pools in Pacific Northwest old-growth coniferous forests. Seventy-nine pedons in 18 western Washington and Oregon forests were sampled to a depth of 100 cm. The 2-mm fraction by airdrying, physically crushing soil, and sieving; C was determined by Leco combustion. The >2-mm fraction contained up to 46% of the whole-soil C and averaged 23% for the seven forests that had C in that fraction. Following treatment with...

CalPro is an add-in program developed to work with Microsoft Excel to simulate the growth and management of uneven-aged mixed-conifer stands in California. Its built-in growth model was calibrated from 177 uneven-aged plots on industry and other private lands. Stands are described by the number of trees per acre in each of nineteen 2-inch diameter classes in two species groups, hardwoods and softwoods.CalPro allows managers to predict stand development by year and for many decades from a specific initial state. Users can choose cutting regimes by specifying the interval between harvests...