タイトル（掲載誌）JIRCAS Working Report : Improvement of Utilization Techniques of Forest Resources to Promote Sustainable Forestry in Thailand
一般注記The effects of first thinning on growth and stem form of teak stands were examined in Uttaradit Province, Northern Thailand. In this study, a randomized complete block design with 3 replications was used, and thinning from below (low thinning) was applied as the first thinning. The thinning treatments were as follows: removal of basal area at the levels of 0% (unthinned), 30% (moderate), and 50% (heavy). The measurement period after thinning was 4 years. The results of the study revealed that heavy thinning provided the largest mean basal area and mean stem volume of individual trees in the stands compared with the other treatments. The total stand volume increase in production per rai (0.16 ha) was largest in moderate thinning plots and differed significantly from unthinned plots, but did not differ significantly from heavy thinning plots. The moderate and heavy thinning intensities reduced the annual stand volume increase by 23% and 64%, respectively, related to the mean stand volume increase of thinned stands before thinning was executed, whereas those in unthinned plots reduced by almost 99%.
Part of the total stand volume production of unthinned plots was lost through natural mortality. In the thinned plots, naturalmortality was considerably lower compared with the unthinned plots. The mean diameter at breast height (DBH) increment of all trees as well as the mean DBH increment of the dominant trees was enhanced with increasing thinning intensity, but there was no significant difference among the thinned and unthinned plots. However, the mean DBH increment of all trees in unthinned plots was as much as those in moderate thinning plots. In contrast, total height increment of all trees and the dominant trees were not affected by thinning intensity. Live-crown ratio, slenderness ratio, and absolute form factor of the trees in the stand were affected by different thinning intensities. Live-crown ratio increased with greater thinning intensity. On the other hand, slenderness ratio decreased with greater thinning intensity. The absolute form factor was smallest in unthinned plots, and different thinning intensities had clear effects on the absolute form factor. Thus, thinning intensity resulted in improved growth and yield of stands after thinning as well as individual tree size and tended to have positive effects on stem form.
一次資料へのリンクURLjircas_working_report85-_19-30 （fulltext）
連携機関・データベース国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）
提供元機関・データベース国際農林水産業研究センター : 国際農研機関リポジトリ