EVALUATION OF FOREST CANOPIES BY PHOTOGRAPHY
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
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A technique for evaluating forest canopies was developed based on the use of a divergent lens system to obtain hemispherical photographs of tree crowns. The photography was processed from 35 mm film and enlarged as a silhouette, and the light transmission was measured with a specially fabricated macrodensitometer. It is shown by application to a variety of problems in diverse geographical areas that this technique can be used for measuring both temporal and spatial changes in the canopy, for estimating the shade light climate, and for specifying the probability of target detection through a canopy. Data are presented to analyze changes caused by explosions, radioactivity, growing season, and vegetation types. The geometry of gaps in three crowns is discussed and the nature of shade light quality under forests is illustrated.