Treesearch
Search National Treesearch
Displaying 5,691 - 5,700 of 6,855 Publications
- Three arboreal rodents are sensitive indicators of forest ecosystem function in the Pacific Northwest. The northern flying squirrel (Glaucomys sabrinus) is mycophagous, cavity-nesting, and a major prey of the spotted owl (Strix occidentalis). The red tree vole (Phenacomys longicaudus) is restricted to trees and may prove sensitive to forest fragmentation. The Douglas' squirrel (Tamiasciurus douglasi) responds sharply to fluctuations in conifer seed abundance. Live-trapping and mark and recapture methods can be used to estimate densities of northern flying squirrels and some other rodents...AuthorsAndrew B. Carey, Brian Biswell, Joseph W. WittKeywordsSourceGen. Tech. Rep. PNW-GTR-273. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 24 pYear1991
- Seed weight, time of emergence, and three measures of seedling size were recorded for 39 open-pollinated Douglas-fir (Pseudotsuga menziesii var. menziesii[Mirb.] Franco) families in order to assess family variation in seed weight and emergence, and the influence of these seed traits on early growth. Families were planted both as ungerminated seed and as recent germinants to test whether using germinants minimized seed effects on early growth. To evaluate the effect of competition on the relationships of seed weight and rate of emergence to seedling size, individuals of families were...AuthorsJ.B. St. Clair, W.T. AdamsKeywordsSourceForest Science. 37(4): 987-997Year1991
- Statistics on forest area, total gross and net timber volumes, and annual net growth and mortality are presented from the 1983-84 timber inventory of the Stikine Area, Tongass National Forest, Alaska. Available timberland area is estimated at 1.2 million acres, net growing stock volume at 7.2 billion cubic feet, and annual net growth and mortality at 18.8 and 57.0 million cubic feet, respectively.AuthorsGeorge Rogers, Wlllem W.S. van HeesSourceRes. Bull. PNW-RB-185. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 19 pYear1991
- Three experiments were conducted to determine effects of N and P fertilizers on growth and levels of plant-tissue nutrients of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Both pole-size trees in closed-canopy stands and potted seedlings were use d . Soil series were Bunker for Douglas-fir and Klone for western hemlock in experiments 1 and 3, and Vesta in experiment 2. For each species in experiments 1 and 2, P and N fertilizers were tested in six or eight treatments using factorial design. In experiment 3, N and P fertilizers...AuthorsM.A. Radwan, J.S. Shumway, D.S. Debell, J.M. KraftSourceCanadian Journal of Forest Research. 21: 1431-1438.Year1991
- Construction specifications and illustrations are provided for several types of barbed wire and pole fences, gates, cattle guards, stiles, spring developments, water troughs, stock ponds, trick tanks, and livestock access trails.AuthorsH. Reed Sanderson, Thomas M. Quigley, Emery E. Swan, Louis R. SpinkKeywordsSourceGen. Tech. Rep. PNW-GTR-250. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 126 pYear1990
- This history, from the memoirs of the entomologist in charge, describes the first large-scale cooperative bark beetle control project funded by Congress in the Western United States. It describes relations between the Forest Service, Bureau of Entomology, and private timber owners, how the project was organized and conducted, and results of the control measures. The editor provides information and interpretations from additional sources and human interest background on participants of this pioneering forest insect control project.AuthorsH.E. BurkeKeywordsSourceGen. Tech. Rep. PNW-GTR-249. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 55 pYear1990
- Height growth and site index curves were constructed from stem analyses of mature western white pine (Pinus monticola Dougl. ex D. Don) growing in high-elevation forests of the Cascade Range in the Mount Hood and Gifford Pinchot National Forests of Oregon and Washington, respectively. Alternate systems using reference ages for site index of 50 and 100 years breast height are presented. Differences among systems and their causes are briefly discussed.AuthorsRobert O. Curtis, Nancy M. Diaz, Gary W. ClendenenSourceRes. Pap. PNW-RP-423. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 14 p.Year1990
- Lumber recovery information from live and beetle-killed ponderosa pine (Pinus ponderosa Dougl. ex Laws) in the Colorado Front Range is presented. No significant difference in lumber volume was found among the samples. Significant differences were found in lumber value among the live, 1-year-dead, and 3- to 5-year-dead samples. About 10 percent of the value was lost in the first year after death, primarily because of blue stain. Checks and splits, wood borers, and rot caused additional loss in subsequent years.AuthorsSusan Willits, Richard O. Woodfin, Thomas A. SnellgroveKeywordsSourceRes. Pap. PNW-RP-428. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 14 pYear1990
- Effects of genotype and nitrogen fertilizer on growth and shoot nutrients of western hemlock seedlings were determined by using 11 open-pollinated families from coastal Oregon and Washington. The families differed significantly in growth, initially and after one growing season after treatment. All seedlings responded well to fertilizer, and fertilization significantly affected concentration and content of shoot nutrients. Nutrient levels also differed significantly among families, but there were only few significant family x fertilizer interactions. Results suggest that selections of...AuthorsM.A. Radwan, D.S. DeBell, J.E. WilcoxKeywordsSourceRes. Pap. PNW-RP-426. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 10 pYear1990
- From 1977 through 1986, herbage and browse production was sampled on 619 sites representing 10 ecosystems and 51 resource units on the Oregon Range Evaluation study area. We determined the effects of six range management strategies and cultural treatments on combined herbage and browse production. Mean herbage and browse production on the forest ecosystems was 145 kilograms per hectare and ranged from 53 to 194 kilograms per hectare. On the range ecosystems, production averaged 417 kilograms per hectare and ranged from 224 to 1037 kilograms per hectare. Production for strategies among...AuthorsH. Reed Sanderson, Thomas M. Quigley, Arthur R. TiedemannSourceRes. Pap. PNW-RP-419. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 15 pYear1990