The spruce budworn (Choristoneura fumiferana, Clem.) infestation is continuing at epidemic levels throughout northeastern North America's spruce-fir forest. This article describes research to identify at which minimum scale aerial photography can be used to assess budworm damage. Color and color-infrared imagery taken at several times of the year and interpreted by using several viewing methods have been evaluated to find if new infestations, tree mortality, and stands requiring spraying to prevent excessive future mortality can be identifed. Color photography obtained in the summer at the height of needle browning was best for interpreting current moderate or heavy budworm feeding. Early summer or fall photos taken when the currently fed needles were not on the trees were most suitable for evaluating past feeding and overall tree condition. Mortality was best identified on color-infrared early summer or fall imagery. Scale and viewing method greatly influenced interpretation accuracy. Individual tree detail could be observed at scale of 825 feet- per-inch and larger. Tree and stand condition were most accurately interpreted by using a 7X monocular viewer on the backlighted, outer portions of the frame. Mortality counts were equally-accurate using two, four, or seven power stereoscopic and seven power monoscopic viewing at scales of 2640 feet-per-inch and larger.

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  • Corporate Authors:

    American Society of Photogrammetry

    105 North Virginia Avenue
    Falls Church, VA  United States  22046
  • Authors:
    • Ashley, M D
    • Rea, J
    • Wright, L
  • Publication Date: 1976-10

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Filing Info

  • Accession Number: 00142578
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 15 1976 12:00AM