- 期刊
紅檜人工林疏伐後4年對林分及單木層級之影響
Thinning Effects on Stand and Tree Levels of Taiwan Red Cypress (Chamaecyparis Formosensis Matsum.) 4 Years After Thinned
摘要
本研究之目的旨在探討紅檜(Chamaecyparis formosensis Matsum.)人工林經疏伐4年後對林分及單木層級之影響，研究地區位於台灣中部大安溪事業區第121及123林班之紅檜人工林，該林分於2004年進行疏伐處理，採用強度疏伐（保留株數800株ha^(-1)）、中度疏伐（保留株數1000株ha^(-1)）及不疏伐處理之對照區，並設置永久樣區進行林分疏伐後之監測。本研究主要採用永久樣區自疏伐後4年的資料進行分析，結果顯示強度疏伐及中度疏伐處理可明顯促進材積生長率且明顯地高於對照區，強度疏伐林分、中度疏伐林分及對照區分別為6.08、6.12及4.22% yr^(-1)。疏伐林分之直徑分布以Weibull機率密度函數模擬，經Kolmogorov-Smirnov統計測驗檢測所得其模擬效果良好。林分於疏伐前後其直徑分布有著明顯差異。此外，在單木層級Heygi競爭指數和胸徑生長呈現倒J型的負相關。
並列摘要
The purpose of this study was to show the thinning effects on stand and tree levels of Taiwan red cypress (Chamaecyparis formosensis Matsum.). The study area was located in Ta-An-His Working Circle at No. 121 and 123 compartments of central Taiwan. Three treatments, i.e., heavy thinning (remaining 800 trees ha^(-1)), middle thinning (remaining 1000 trees ha-1) and no thinning, were practiced in the Taiwan red cypress stand in 2004. On the other hand, permanent plots were set up for monitoring stand dynamics after thinned, and the data of our study were collected and analyzed from these plots through after thinning to 4 years. We found that heavy thinning and middle thinning could significantly promote volume growth rate than unthinning stands, where heavy thinning, middle thinning and unthinning stands were 6.08, 6.12, and 4.22% yr^(-1), respectively. The Weibull probability density function was used to model stand diameter distribution with different thinning treatments, and good simulative effects were obtained by the Kolmogorov-Smirnov test. We also found that the stands before and after thinning had an obvious difference in diameter distribution. In addition, the relationship between the Heygi competition index and DBH growth appeared a reversed J-shape at tree level.