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Estimated Fraser Fir Mortality and Balsom Woolly Aphid Infestation Grend Using Aerial Color Photography

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A stratified-systematic sample of photo plots was used to estimate the number of dead Abies fraseri (Pursh) Poir per acre of defined type on 22,000 acres near Mt. Mitchell, North Carolina. The sample design included 215 one-acre plots stratified in 1:7920 scale aerial color photographs by mortality classes. Fir mortality and live spruce and fir were counted on the photos using 4.5 power stereoscopic magnification. Thirty photo plots were located on the ground to measure aphid populations and to count fir mortality and live spruce and fir. From the photo and' ground counts of mortality and live trees, regression lines were developed to adjust photo estimates made from the larger photo sample. The best relationship included dominant, codomlnant, and intermediate trees (r = 0.7). The first year adjusted estimate of dead Fraser fir per acre was 13.9 -- 0.8 trees. Each year the 215 photo plots were transferred to new color photos for re-estimates which showed a definite upward trend for four years and reached 21.3 q- 1.0 dead fir per acre in 1963. Photo plots in the 1-50 percent mortality range were the best indicators of trend. Since balsam woolly aphid damage is accumulative, equations were developed to compute the index of accumulated fir mortality on a rating scale of 0-4. The survey design used in this study was three times as efficient as a simple random sample of equal intensity. The cost of the original survey was 11 cents per acre and each resurvey 5 cents per acre.

Document Type: Journal Article

Affiliations: Forest Entomologist, Southeastern Forest Expt. Sta., Forest Service, U.S. Dept. Agric., Asheville, North Carolina

Publication date: 1967-09-01

More about this publication?
  • Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
    Forest Science is published bimonthly in February, April, June, August, October, and December.

    2015 Impact Factor: 1.702
    Ranking: 16 of 66 in forestry

    Also published by SAF:
    Journal of Forestry
    Other SAF Publications
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