- 期刊
臺大實驗林溪頭營林區西川試驗地柳杉生長量之研究
Study on Growth of Cryptomeria japonica D. Don at the Nishikawa Plot of NTUEF Xitou Tract
摘要
本研究選用國立臺灣大學實驗林溪頭營林區西川試驗地進行柳杉人工林生長量之研究。該試驗地自1921年設立來至2011年止已進行40次每木調查，其試驗地並於1928、1940、1943、1947年經歷四次疏伐。研究結果顯示至2011年之平均胸徑為47.8cm，平均樹高為29.2m，其平均生長量為5.59m^3ha^(-1)，蓄積量為798.41m^3ha^(-1)。將平均胸徑與平均樹高連年生長情形使用Gompertz Curve進行套配，大致能符合其生長趨勢；依此繪製平均木材積之連年生長與平均生長曲線，其交界點為理想伐期齡（1970年，林齡58年）。研究中使用Weibull三參數分布曲線探討林分直徑級結構之變化情形，其參數之變化可反應林分生長之變化趨勢。更精確之柳杉生長量推估及林分結構之變化仍有待後續之持續調查與適宜生長模式之建立。
並列摘要
This study focuses on the growth of Cryptomeria japonica D. Don at Nishikawa Plot of NTUEF Xitou Tract. This plantation site had been investigated for 40 times since established in 1921. Four thinning operations had also been done in 1928, 1940, 1943 and 1947. The recent investigation in 2011 shows that the average DBH (Diameter at Breast Height) is 47.8 cm, the average height is 29.2 m while the average increment growth is 5.59m^3ha^(-1) and the storage is 798.41m^3ha^(-1). Second, we fit all the DBH and tree height data using Gompertz curve, the result shows the growth trend fits well with the curve. Next the variation of the stand structure is illustrated using 3-parameter Weibull distribution probability curve. From the variation of three parameters reveals the trend of growth of the stand. Finally we plot the average and successive annual growth curve and the intersection point of these two curves is the ideal rotation age which is estimated at the age of 58 years in 1970. More accurate estimation of growth of Cryptomeria japonica D. Don relies on the consistent investigations and establishment of suitable growth model in the future.