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9,154 results found
Bulk density and soil resistance to penetration were measured in ten, 3- to 11-ha operational units in overstocked, mixed-conifer stands in northeast Washington. Resistance was measured with a recording penetrometer to the 33-cm depth (13 in) at 10 stations on each of 8 to 17, 30.5-m-long, randomly…
Author(s): Johanna D. Landsberg, Richard E. Miller, Harry W. Anderson, Jeffrey S. Tepp
Keywords: Soil strength, penetration resistance, cone penetrometer, bulk density, commercial thinning, northeast Washington, ashy soils, yarding equipment, soil disturbance
Source: Res. Pap. PNW-RP-551. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 35 p
Year: 2003
The effects of partial cutting on plant species richness, community structure, and several understory species that are important for deer forage were evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12–96 years ago when 16- 96% of the former…
Author(s): Robert L. Deal
Source: Canadian Journal of Forest Research. 31: 2067-2079
Year: 2001
Knowledge of the community structure of ectomycorrhizal fungi among successional forest age-classes is critical for conserving fungal species diversity. Hypogeous and epigeous sporocarps were collected from three replicate stands in each of three forest age-classes (young, rotation-age, and old-…
Author(s): J.E. Smith, R. Molina, M.M.P. Huso, D.L. Luoma, D. McKay, M.A. Castellano, T. Lebel, Y. Valachovic
Keywords: ectomycorrhizal fungi, sporocarp production, forest succession, Pseudotsuga menziesii, Tsuga heterophylla zone, biodiversity
Source: Canadian Journal of Botany. 80: 186-204
Year: 2002
The H.J. Andrews Experimental Forest is a world renowned center for research and education about the ecology and management of forests and streams. Located about 50 miles (80 km) east of Eugene, Oregon, the Andrews Experimental Forest lies in the Blue River Ranger District of the Willamette…
Author(s): Art McKee, Pamela Druliner
Keywords: H.J. Andrews Experimental Forest
Source: [brochure]. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station
Year: 1998
Rangelands comprise about 42 percent of the land area of the United States and provide vital land functions such as watershed, multiple-use, recreation, and other amenities. Currently, we do not know the status and trends of many of our nation's rangelands, and consistent protocols for describing…
Author(s): Renee A. O'Brien, Curtis M. Johnson, Andrea M. Wilson, Van C. Elsbernd
Keywords: rangeland health, functionality, indicators, bare ground, noxious weeds, species composition
Source: Gen. Tech. Rep. RMRS-GTR-104. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 13 p.
Year: 2003
How do we promote resistance to disturbance, resilience when disturbance does occur, and forest health in general when forests and landscapes are actively managed for a variety values? How do we manage for sustainability when humans and their consumption patterns are munching up the earth at…
Author(s): Sally Duncan
Source: Science Findings 54. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p
Year: 2003
Within-stand variation in understory species composition and biomass was studied in 16 even-aged stands of mixed red alder-Sitka spruce-western hemlcock (Alnus rubra-Picea sitchensis-Tsuga heterophylla) forest. The sites were upland sites, and the stands were 28-39 years…
Author(s): T.A. Hanley, J.C. Barnard
Keywords: Red alder, Alnus rubra, Sitka spruce, Picea sitchensis, western hemlock, Tsuga heterophylla, secondary succession, understory, biomass, forests
Source: Canadian Field-Naturalist. 112(4): 647-652
Year: 1998
Nitrogen-fixing bacteria associated with mycorrhizal fungi and mycorrhizas can be demonstrated with microaerophilic procedures. The chemical substrates in mycorrhizal fungi or mycorrhizas often stimulate the growth and nitrogenase activity of the associated N2 fixers. In addition, the associated…
Author(s): C.Y. Li, E. Strzelczyk
Keywords: Microbial processes, ecological functions, microbial interactions
Source: Phyton (Horn, Austria). 40(4): 129-134
Year: 2002
Knowledge of regional-scale patterns of ecological community structure, and of factors that control them, is largely conceptual. Regional- and local-scale factors associated with regional variation in community composition have not been quantified. We analyzed data on woody plant species abundance…
Author(s): J.L. Ohmann, T.A. Spies
Keywords: Canonical correspondence analysis, forest ecology, gradient analysis, Oregon, plant communities, regional vegetation analysis, species diversity, variance partitioning, woody plants
Source: Ecological Monographs. 68(2): 151-182
Year: 1998
1. We examined how rapidly soils can change during secondary succession by observing soil development on 350-year chronosequences in three pristine forest ecosystems in south-east Alaska. 2. Soil surfaces, created by different windthrow events of known or estimated age, were examined within each of…
Author(s): B.T. Bormann, H. Spaltenstein, M.H. McClellan, F.C. Ugolini, K. Cromack, S.M. Nay
Keywords: C accumulation, chronosequence, disturbance frequency, podzolization, soil development, soil disturbance, windthrow
Source: Journal of Ecology. 83: 747 - 757
Year: 1995