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Photo stratification improves northwest timber volume estimates.Author(s): Colin D. MacLean
Source: Res. Pap. PNW-RP-150. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 16 p
Publication Series: Research Paper (RP)
Station: Pacific Northwest Research Station
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DescriptionData from extensive timber inventories of 12 counties in western and central Washington were analyzed to test the relative efficiency of double sampling for stratification as a means of estimating total volume. Photo and field plots, when combined in a stratified sampling design, proved about twice as efficient as simple field sampling. Although some gains were made by stratifying into only two classesforest and nonforest substantially greater gains accrued when the forest plots were further stratified into timber volume classes. Optimum allocation of field plots was only slightly more efficient than proportional allocation.
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CitationMacLean, Colin D. 1972. Photo stratification improves northwest timber volume estimates. Res. Pap. PNW-RP-150. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 16 p
KeywordsDouble sampling, photo sampling, timber volume estimates
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