六龜地區臺灣杉人工林之生長

The Growth of Taiwania cryptomerioides at Lu-Kuei Area

林照松(Chao-Song Lin) ； 洪富文(Fu-Wen Horng)

《林業試驗所研究報告季刊》 6卷3期 (1991/09) Pp. 229-248

https://doi.org/10.7075/BTFRI.199109.0229

摘要

就六龜地區選擇7、8、10、15、17及18年生的臺灣杉人工林各三個0.05公頃的試區進行調查，每個試區分別測得樹高(HT)、胸徑(DBH)、枝下高(LH)及枯枝高(DH)的值，經由計算求得樹冠長(LC)、樹冠比(RC)、枝下比(HR)、枝下形狀比(SR)、形狀比(S)及材積值。再利用迴歸模式來分析胸徑、林齡與其他性態值間的關係。
結果顯示出胸徑與樹高、樹冠長、樹冠比及材積間具有高度正相關；胸徑與枝下比、枝下形狀比及形狀比間則有高度的負相關。枝下形狀比為林木生長活力的良好指標。
在六龜地區，臺灣杉人工林在栽植密度為2000株／ha，於17年生時，其材積可達220立方公尺/ha，然而從樹冠長、枝下比、胸高斷面積及材積增加的情形來判斷人工林的發展，10年生可進行非商業性疏伐，15~18年生之間則可結合打枝作業來施行商業性疏伐。

關鍵字

林分密度控制 ； 枯死枝下高 ； 人工修枝

並列摘要

At Lu-kuei area, three 0.05 ha temperary plots in each Taiwania Cryptomerioides with age of 7, 8, 10, 15, 17 and 18-year-old, respectively, were selected. For every tree in each plot, tree height, DBH, clear-length, attached dead branch length were measured, and crown-length, live-crown ratio, clear-length ratio, clear-length to diameter ratio, stem height to diameter ratio, tree volume, were calculated. For the plot, basal area, and volume per hectare were estimated. Relationship of DBH, age and the other attributes, were analyzed with regression models.
As the results indicated, high positive exponential relation is existed between DBH and HT, crown-length, live-crown ratio and tree volumes for each age studied, and high negative exponential relation is existed between DBH and clear-length ratio. Clear-length to diameter ratio can be a good indicator for tree growth vigor. At Lu-Kuei area, Taiwania plantations with initial plenty density of 2000/ha, can reach a volume of 220m^3/ha, However, judgde from the trend of crown length, clear-length, clear-length ratio, basal area and volume increment with plantation development, non-commercial thinning can be started at age of 10 years, and commercial thinning in combination with pruning can be started between ages of 15~18 years.

並列關鍵字

stand density control ； attached dead brank length ； artificial green pruning