According to slope direction and position of the distribution of Juglans mandshurica natural secondary mixed forest in 12 sites of Changbai Mountain in Jilin Province, and combined with the age structure of J. mandshurica, we set up 109 plots. Based on the age-tree height data, we complied the site index of the forests. We used the three times tree height standard deviation method to eliminate abnormal data, 379 pairs age and tree height data were obtained from the 80 plots. Then, we used seven mathematical models for comparison and got simplex site index-oriented curve equation as H=28.0181(1-e-0.0341A)1.0503. The coefficient of determination R2 and the sum of squared residuals were 0.85 and 0.89, respectively, the base age was 50 years, the exponential interval was 2 m, and 7 site index curves of 16-28 m were obtained. According to different site types, polymorphic sites index model was established, and the power function fitting effect was best. Its equation was H=B0tB1, in which B0=10-9e0.9213SI, B1=-0.2139SI+5.6183. Finally, the polymorphic site index model equation was H=10-9e0.9213SIt-0.2139SI+5.6183. The exponential difference method and drop point test were conducted to check the accuracy of the two site index models. The results showed that the polymorphic site index had higher precision and it could accurately reflect the difference in tree height growth under different site types of J. mandshurica. Therefore, it could evaluate the site quality of natural secondary mixed forests of J. mandshurica in Changbai Mountain area of Jilin Province.
依据吉林省长白山胡桃楸天然次生混交林12个典型区域的坡向、坡位分布,结合胡桃楸龄级,布设样地109块,以年龄-树高数据为材料,编制了吉林省东部山区胡桃楸天然次生混交林立地指数表.结果表明: 应用3倍树高标准差法剔除异常数据,最终得到80块379对胡桃楸不同龄级的年龄与树高数据,运用7个数学模型进行比较,确定了单形立地指数导向曲线方程式: H=28.0181(1-e-0.0341A)1.0503,决定系数R2为0.85,残差平方和为0.89,基准年龄为50年,指数级距为2 m,得到了16～28 m的7条立地指数曲线.根据不同立地类型,建立了多形立地指数模型,幂函数拟合效果较好,即H=B0tB1,其中B0=10-9e0.9213SI,B1=-0.2139SI+5.6183,最终得到了多形立地指数模型方程式H=10-9e0.9213SIt-0.2139SI+5.6183.指数级差法和落点检验法对2种立地指数模型的精度检验表明,多形立地指数的精确度较高,能够准确地反映胡桃楸不同立地类型间树高生长的差异,可用于吉林省长白山区胡桃楸天然次生混交林立地质量评价.
Keywords: Juglans mandshurica; guide curve; natural secondary mixed forest; polymorphic site index model.