Assessing spruce budworm damage with small-format aerial photographs

Abstract

Methods of evaluating forest damage are designed to provide information for detection, control, and preventative management. In this study the use of small-format aerial photographs to assess spruce budworm, Choristoneurafumiferana (Clemens), damage was evaluated. A procedure was developed to identify spruce–fir stand vulnerability and establish inventory data for silvicultural management considerations. Large-scale (1:4800) 35-mm color positives of eight spruce–fir stands were obtained in July and August 1979. Defoliation intensity and tree mortality of host species were the parameters used to assess damage severity. Individual stands were assigned separate damage rating values based on aerial and ground survey evaluations of defoliation and mortality. Comparison of aerial and ground damage severity ratings was accomplished with a contingency table. Results show photointerpretation of forest damage condition matched ground inspection in seven of eight stands surveyed.