| Abstract: | Data from 16 forest stands were used to assess the accuracy of aerial photo interpretation of areas with thin soil cover and bedrock outcrops. Thin soil cover was defined as soil depth less than 10 cm, including outcrops. The portion of the area with thin soil cover within the stands was interpreted by four experienced persons according to a 4 x 4 Graeco‐Latin square design. IR‐color photographs and panchromatic black‐and‐white photographs at the scales 1:15 000 and 1 :22 000 were used. The overall differences between photo interpreted portions and the ground reference portions was not significant. According to an analysis of variance, the interpretation results were slightly better for IR‐color film than for the black‐and‐white film (10% level). The effect of scale was far from significant. The effect of stand density was highly significant. Thin soil cover was underestimated in dense stands. In the future, calibration plots with known characteristics should be used in order to achieve successful photo interpretation of areas with thin soil. |
