柳杉人工林单木材积生长模型的研究

本文将柳杉人工林单株木的林积生长量作为年龄、地位指数、竞争指数的函数，建立单木生长模型。研究结果表明：简单竞争指数优于竞争压力指数，而在简单竞争指数中，竞争木取６株和８株差别不大，均优于竞争木取４株。进一步的分析表明：在不受人为干扰的林分中，竞争木取６株和８株的简单竞争指数在一定时期内保持相对稳定的状态，与林分年龄和立地质量关系不密切，而与胸径之间存在着密切的相关关系。其值随着胸径的增大而减小，二者之间的关系用双曲线和幂函数拟合较为适宜，由此建立的简单竞争指数预估模型，扩大了单木生长模型的运用范围。在理论上和实践上均有重要的意义。

Study on Single Tree Volume Growth Model for Cryptomeria fortunei Plantation

Taking age, site index and competition index as arguments, the single tree volume growth model is established for Cryptomeria fortunei plantation in this paper. During modeling,It is the key to calculate competiton index,the calculating trsults indicate that selecting simple competition index is superior to competition suppressed index for establishing model.It is the better to select six competition trees adjacent to objective tree for calculating simple competition index.In undisturbed stands, simple competition index isn't relative to age and site index but relative to HD,that is decreasing with the DH increading, and it is the better for simulating this relationship with power function or hyperbola. Based on foregoing condition,the predicting model of simle competition index is established, that may enlarge the appliable range of the single tree volume growth model.