本研究位於臺灣大學實驗林溪頭營林區臺灣杉長期試驗地，旨在探討臺灣杉長期生長的調查結果。該試驗地自1938年造林，於22年生時 (1960年) 設立長期試驗地，迄2007年為止共進行11次地面調查。研究結果顯示，至69年生之平均胸徑為58.2公分，平均樹高為29.2公尺，每公頃蓄積量達1200立方公尺。至69年生的胸徑生長尚未有減緩趨勢，初期的樹高生長量相當良好。林分的材積平均生長最大時為41年生，此為森林經理學常用之收穫最大輪伐期，由Gompertz生長曲線模擬臺灣杉平均木材積收穫最大輪伐期為96年。以平均木或單木生長的模式來推估林分的輪伐期將可能產生較大的落差。

This study aims on the long-term growth trend of Taiwania cryptomerioides at experimental plot of Xitou area. The plot was planted in 1938 and set up as a long-term experimental plot started in 1960 (22 years old for the plantation). Eleven inventories were surveyed until 2007. The investigations showed that the average DBH (Diameter at Breast Height) was 58.2 cm and the average height was 20.2 m with volume stock per hectare to be 1200 m3 (69 years old for the plantation). No decrease trend was observed for the DBH and growth of tree height. The initial growth period was quite good. In addition, the maximum of mean annual volume stock for growth increment was 41 years for the plantation, which indicates the normal rotation of the greatest volume of forest management. By fitting the mean DBH and tree height data with the Gompertz curve, the average rotation of greatest production is 96 years, which differs substantially with the mean tree or individual tree growth pattern.