Partial sloping forms around Cryptomeria trees in a heavy snow region and their growth
1993
Yamaya, M. (Yamagata univ., Tsuruoka (Japan). Faculty of Agriculture) | Tsukahara, H.
Contour maps, 10 to 25 cm high of five Cryptomeria stands, eight to seventy-years-old, in a heavy snow region were drawn accurately following a topographic survey using a light wave telemeter. The ideal diameter of circles around points, of different sizes from 1 to 8 m in diameters was about four meters in accordance with minimum variances of two kind of micro-topographic parameters, one following along a contour line and the other plotting the differences in angles between the upper and downward slopes around the points. In the cases of the studied stands the number of convex and concave circles in both directions, going upward and downward, and the horizontal slope were almost the same. On the stand eight-years-old, there were small differences in numbers between convex and concave circles around the trees. However, there was a conspicuous difference in the number increasing with age. At ages of twenty-eight to seventy, the number of concave circles around surviving trees decreased remarkably. Sixty-nine and seventy-years-old trees on the convex circles had less decreases in numbers, and most of the trees had grown well and had little stem-butt crookednesses. Depths and weights of snowpacks for the concave circles clearly were more than for the convex circles during winter. It was suggested that the decreasing numbers of trees on the concave circles were because of heavy snow pressures
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