【目的】地位指数法是森林立地质量评价常用的一种方法, 优势高又是地位指数模型中重要的参数。本研究以杉木优势高生长为切入点,使用与年龄无关方法建立杉木人工林的优势高生长模型,模拟在林分年龄未知的情况下预测杉木人工林优势高。【方法】利用福建省将乐国有林场杉木人工林的65个固定样地连续观测数据,基于Richards方程、Lundqvist-Kolf方程和Hossfeld方程3个树高生长方程,使用与年龄无关的方法建立了9个优势高生长模型。模型检验使用决定系数、平均误差和均方根误差3个统计指标来确定最佳模型。【结果】构建的9个优势高生长模型都具有较好的拟合优度,其中以Hossfeld方程为基础方程,以参数a作为林分因子扩展参数推导而来的模型为最佳模型,而且模型参数年龄差Δt越小,模型预测精度越高。【结论】与年龄无关的地位指数模型能够准确地拟合和预测优势高生长。在异龄林中或林分年龄难以获得时,建议采用与年龄无关的地位指数模型来评估立地质量。

【Objective】 The site index method is a common way for forest site quality evaluation, and dominant height is an important parameter in the site index model. The purpose of this study was to develop dominant height growth models for Chinese fir plantation using age-independent methods to predict dominant height growth under the scenario that sand age remains unknown. This kind of age-independent difference approach formulation is established to stimulate the growth of trees and stands. It is used to predict the growth at the end of every period by the observation at the beginning of the period.【Method】 With data of 65 permanent sample plots in Jiangle State-owned Forest farm of Fujian Province, nine age-independent models were developed respectively based on Richards, Lundqvist-Kolf and Hossfeld growth equation. Three statistics indicators including coefficient of determination(R²), mean error and root mean square error and graphical analysis were considered to evaluate models and choose the best one. This method has little application at home but it can improve the situation that ages are difficult to get or not able to attain. It can provide a new way to establish dominant height model and it will make site index evaluation become a more convenient thing.【Result】 The nine models showed robust goodness of fit, and the best one was identified as the model derived from Hossfeld function with parameter a as expand parameter of stand factors. Besides, its predictive accuracy is higher for short age intervals.【Conclusion】 Age-independent site index model can accurately fit and predict dominant height growth, it is accurate and effective for site index model derivation, so it is recommended that age-independent site index model should be used to estimate site quality for uneven-aged stands or age unknown situations.