北京山区侧柏人工林立地指数表的编制

Compilation of site index table for plantations of Platycladus orientalis in Beijing mountainous area

侧柏是北京市山区主要的造林树种,其人工林面积约占全市森林总面积的25.96%。该文在利用二类清查数据分析侧柏人工林主要分布区立地条件的基础上,利用全市314块调查样地的侧柏优势木资料,采用优势木树高与年龄关系的常用数学模型,研制北京山区侧柏人工林的立地指数表。结果表明：对数曲线方程lgH=0.008＋0.562 lgA是最适合的导向拟合曲线;侧柏人工林的标准年龄应定为40年,在4~13 m范围内可划分为10个立地指数级。选用相对优势高法展开导向曲线编制形成立地指数表。检验结果表明：所编立地指数表精度高、适用性强,能够客观评价北京山区侧柏人工林的立地质量,提高生长和收获模型的精度;同时还能为其相似地区所借鉴,从而使该树种在林业和环境建设方面发挥更重要的作用。

Platycladus orientalis is an important afforesting tree species in Beijing mountain area. Its plantation area is 25.96 percent of total forest area in Beijing. In this paper, the forest management inventory data were used to analyze the main distribution of site conditions for plantations of P. orientalis. The data of dominant trees from 314 sample plots in various site conditions were used to construct site index table by fitting the generalized mathematical models of age and height. The results indicated that logarithm curve equation had the best fit among the selected curves. The standard age was set to 40 years, and 10 index classes were divided within 4 -13 m. Site index table was constructed by the expansion of the guide curve using comparative dominant height method. The results showed that the site index table is applicable and accurate in evaluating the site quality of P. orientalis plantation in Beijing mountain area, and also is important to improve the accuracy of growth and yield models. The site index table can be referenced by the species in similar regions and make this species play a more important role in the reforestation and environmental protection.