The mechanism of the occurrence of diameter variance after thinning
1993
Nagashima, I. (Gifu Univ. (Japan). Faculty of Agriculture)
Stand prospective yield tables for Private Forest in a few Prefectures have conventionally been made with the stand density control method. But there are some contradictions in the tables; for example, the diameter variances of co-dominant trees are given in minus value, and the diameter variance of the dominant trees was impossibly larger than that of the total trees. Where the diameter variance was generated to use average diameter, total tree number and total basal area per hectare were listed in the tables. Although the reason for these faults has not been clarified yet, one might suggest that, because of the stand density control method, the viewpoint of stand distribution is lacking within the theory. Supposing that trees were stationed at every grid point with same size of crown to begin competition, a process was successfully examined that thinning does generate stand distribution. To improve the stand yield table, diameter variance or standard deviation has to be furnished, not as an implicit but an explicit item in the table, to give information on log quality
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