Interpretation of Stand Mean Height, Crown Closure and Tree Species on Aerial Photographs From Summer and Autumn

1993

28 S.

31 Lit. Ang.

Bandaufführung

37978

Stand mean height, crown closure and the mixture of tree species were estimated in 52 Norway spruce and Scots pine stands by two interpreters. They used a stereoplotter of the second order, and panchromatic aerial photographs taken the 18th of June and the 8th of October. The maximum systematic error for photo measured mean height was 1.6m. The standard deviation was 1.4-1.8m. For one of the interpreters, the systematic error for mean height measurements was significantly greater for the October photographs than for the June photographs. Only small differences for photo estimated crown closure were detected between the two seasons. The best results of the tree species mixture interpretation were obtained for the October photographs. For both the June and the October photographs, the best interpretation results were found for pure stands. The systematic error was - 1.1 to 1.5 tenths. The standard deviation was 1.6-2.3 tenths.