Treesearch

Throughout their history, conservation science and sustainable-yield management have failed to maintain the productivity of living resources. Repeated overexploitation of economic species, loss of biological diversity, and degradation of regional environments now call into question the economic ideas and values that have formed the foundation of scientific management of natural resources. In particular, management efforts intended to maximize production and ensure efficient use of economic "resources" have consistently degraded the larger support systems upon which these and all other...

Three levels of organic matter removal (bole only; bole and crowns; and bole, crowns, and forest floor) and three levels of mechanical soil compaction (no compaction, moderate compaction, and severe soil compaction) were studied as they influence Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and western white pine (Pinus monticola Dougl. ex D. Don) seedlings following outplanting. Moderate and severe soil compaction significantly reduced nonmycorrhizal root tip abundance on both Douglas-fir and western white pine seedlings (p ≤ 0.05). Ectomycorrhizal root tip abundance...

Tailed frogs (Ascaphus truei) were found in 42 of 80 streams surveyed in Union, Umatilla, Wallowa, and Baker Counties in 1992. At least three size classes of larvae were identified in seven of the streams, thereby suggesting that larvae transform after spending 3 or more years in the streams. The amount of cobble and fines in the streambed best predicted abundance of larvae, whereas, cobble, boulders, slope gradient, and stream buffers best predicted abundance of adults.

Abstract Throughout the Applegate watershed, dense, overstocked, immature stands of mixed conifers and hardwoods and declining stands of mature conifers present significant and complex silvicultural problems. Stand stagnation is common, as is loss of large-diameter conifers from insects and wildfire. Treatments designed to maintain or encourage development of large-diameter conifers have not been tested. In this study, we examined conditions after density management treatments in two adjacent but dissimilar stands: (1) a dense, stagnant, immature stand of 40+-year-old hard-woods and...

This report estimates old-growth forest area and summarizes stand characteristics of old growth in northwestern California National Forests by forest type. Old-growth definitions for each forest type are used.

Changes in fire regimes are expected across North America in response to anticipated global climatic changes. Potential changes in large-scale vegetation patterns are predicted as a result of altered fire frequencies. A new vegetation classification was developed by condensing Kuchler potential natural vegetation types into aggregated types that are relatively homogeneous with respect to fire regime. Transition rules were developed to predict potential changes from one vegetation type to another because of increased fire frequency. In general, vegetation currently associated with warmer or...

Results of the Francis installation of the levels-of-growing-stock study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), begun at stand age 15, are summarized together with results from additional first-thinning treatments started at age 25. To age 42 (5 years beyond the last planned thinning), total cubic-foot volume growth on this mid-site II Douglas-fir plantation has been strongly related to level of growing stock. Growth of lower levels of growing stock exceeded that of the control for only a brief period at age 30. Selection of a "best" treatment would depend on the unit of...

This paper describes use of BIOPAK to calculate size classes of live fuels for shrubs and herbs. A library of equations to estimate such fuels in the Pacific Northwest and northern Rocky Mountains is presented and used in an example. These methods can be used in other regions if the user first enters fuel size-class equations for a given region into a new library by using the library editor supplied with BIOPAK. Fuel size classes can be estimated in three ways: (1) When appropriate plant measurements are available, fuel classes can be estimated directly for species that have equations in...

This publication provides a general picture of the population, economy, and natural resources of the counties in Oregon and northern California. The intent of this report is to provide insight to changes in a county over the last 10 to 20 years, to compare county trends to statewide trends (and state trends to national trends), and to provide information on all the counties in a similar format. This report provides a context and a place to start in examining social and economic trends and conditions, and the importance of natural resources locally. In addition, technical notes for each...

In a nitrogen-deficient plantation in southwest Washington, we (1) compared effects of 224 kg N/ha as ammonium nitrate, urea, and biuret on volume growth of dominant and codominant Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco); (2) determined how 8-year response of these trees to fertilization was related to their distance from a strip of the plantation interplanted with nitrogen-fixing red alder (Alnus rubra Bong.); and (3) observed effects of biuret on understory vegetation. On both sides of the strip centerline, we grouped subject trees into 30 plots of 4 trees each,...