Notes and Observations: Aerial Cruises in Douglas-Fir

A test of aerial photo volume of timber sales in the Douglas-fir forests of the Pacific Northwest was made by three experienced photo interpreters. Cruising techniques employed were similar to the line plot system of ground cruising. Aerial cruises of five out of six sales tested were regarded as satisfactory, and one as unsatisfactory because of its wide volume difference from the log scale. In aerial cruising done without any ground checking, occasional large errors may occur. A potential user should recognize this limitation and use aerial cruising techniques only when accuracy requirements are not great.