• Lawrence, Robert K.
  Cooperative Forestry Research Unit
  
• Houseweart, Mark W.
  Cooperative Forestry Research Unit
  

The Maine Spruce Budworm Growth Impact Study, initiated in 1975, was designed to assess the impact of spruce budworm, Choristoneura fumiferana (Clem.), on tree growth and mortality in softwood and mixedwood stands within the Maine Spruce-Fir Protection District. Tree growth, mortality and budworm-caused defoliation have been measured annually on approximately 400 sample plots. Descriptions of methods and preliminary results of the study have been presented in reports by Ashley et al. (1976), Rea and Houseweart (1978) and Lawrence et al. (1979).

Data have been collected each year by field crews provided by private companies and government agencies cooperating in the study. Because of the large number of field crews, check cruises have been conducted during the course of the project. The major objective of the check cruises has been to determine not only the accuracy but also the uniformity of measurements between and among crews.

The first check cruise was conducted by the James W. Sewall Company during 1975, the initial measurement year. Results of that check cruise, along with a report on sample plot establishment, were published in a Sewall company report. After the Cooperative Forestry Research Unit (CFRU) assumed coordination of the Growth Impact Study in 1976, check cruises were conducted by CFRU staff. This Technical Note reports the analysis of the check cruise data obtained during August and September, 1979.