| 摘要: | 由設置在南澳之銀合歡試區，5年生之林分砍伐後，第2年進行萌蘖去蘖處理：每根株留存1枝、2枝、3枝和不去蘖（留存全部萌蘖）。每小區60平方公尺採完全逢機區集排列，各4重復。林分砍伐後萌蘖長出之前，各處理區內之平均根株直徑無差異，根株直徑均以5-10cm者最多，11-15cm者次之，少於5cm或大於15cm者最少。試區內每個根株之萌蘖在未去蘖前，各種處理之萌蘖數相差不多，去蘗1.5年後，未經去蘖的根株，萌蘖數由每株平均9枝銳減至3.7枝，到6年生時，未經去蘖者、留存3枝者、留存2枝者，各萌蘖之間競爭淘汰，平均每根根株的萌蘖數相近，分別為2.2，1.9和1.8枝。去蘖處理後，2-6年生萌蘖之平均高生長，各處理間每年均無差異。胸徑生長和基徑生長初年（2.5-3年）呈極顯著之差異，以未去蘖處理者累積生長值最大，5年生起各處理直徑生長之差異已不顯著。6年生之萌蘖材積生長，未去蘖者亦比其他各種去蘖處理者為佳。試區內林分之生長，去蘖後第1至5年，每年均呈穩定之成長，但第5年（6年生）各處理林分生長均呈停頓狀態。故萌芽更新，生產薪炭材或紙漿材等工業用材以不去蘖萌蘖為宜。可節省鉅額的造林成本。
Coppice regrowth trial of K8 leucaena was initiated when the plantation at Nan-au (northeastern taiwan) was harvested at five years of age. Shoot retgrowth of four different thinnings was studied in four replications of 60m^2 plots by block complet randamized design. In the begining, the average diameter of stumps in each coppice treatment had no difference, and the diameters of most stumps were in the range of 5-10cm. Before thinning, shoot number per stump of each coppice treatment was almost the same, averaged within 7.8-9.0. The stumps of unthinned plots dropped to 3.7 after 1.5 years. Five years following coppicing (six years old of shoots), the numbers- of shoot per stump in unthinned, 3-shoot and 2-shoot treatments had become 2.2, 1.9 and 1.8, respectively, according to the sever competition among the shoots. Average tree height of each coppice treatment had no difference from 2 to 6 years old plantation statistically. The diameter growth, both DBH and BD, however, revealed significant difference in each treament. The unthinned coppice had greatest values among the four. Moreover, the 6-year volume yield of the unthinned coppice surpassed other three treatments. Since 5 years old, diameter growth in four treatments had become similar. The overall growth of the trial plantation increased rapidly in the first 5 years, but was retard the following year. Therefore, in leucaena coppice management, for producing industrial wood and saving planting coost, no thinning is recommended. |
