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Assessing insect-induced tree mortality across large areas with high-resolution aerial photography in a multistage sampleAuthor(s): Randy Hamilton; Kevin Megown; James Ellenwood; Henry Lachowski; Paul Maus
Source: In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest and Southern Research Stations: 571-580
Publication Series: General Technical Report (GTR)
Station: Pacific Northwest Research Station
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DescriptionIn recent years, unprecedented tree mortality has occurred throughout the national forests owing to insect infestations and disease outbreaks. The magnitude and extent of mortality, coupled with the lack of routine monitoring in some areas, has made it difficult to assess the damage, associated ecological impact, and fire hazard in a timely and cost-effective manner. To aid forest managers in assessing the damage, a cost-effective multistage sampling method, using high-resolution digital aerial photography, was developed to estimate overall mortality across large areas. The method was tested within a 332,000-acre piñon/juniper woodland west of Flagstaff, Arizona, within the Kaibab National Forest. Piñon pine mortality caused by piñon ips bark beetles (Ips confusus (LeConte)) was assessed from high-resolution digital aerial imagery within percent-cover strata with the use of a digital dot grid. The sample revealed that dead trees covered 7.0 ± 0.3 percent of the study area. As a percentage of total tree cover, 20.0 ± 0.8-percent mortality had occurred. The cost to obtain this estimate was approximately $0.04 per acre.
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CitationHamilton, Randy; Megown, Kevin; Ellenwood, James; Lachowski, Henry; Maus, Paul. 2010. Assessing insect-induced tree mortality across large areas with high-resolution aerial photography in a multistage sample. In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest and Southern Research Stations: 571-580.
KeywordsDot grid, imagery, Ips confusus, pinyon, remote sensing, sample.
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