关键词: 土壤化学成分, 土壤化学成分, 海拔, 烟叶, 还原糖, 分类树模型

Abstract:

Density is an important criterion for stand structure. The best stand management density maybe change when the site condition or tree species or age of stands are different in different stands．In this study, using quantification theory typeⅠ and non-linear regression analysis theory, the data from 76 plots had been analyzed and simulated, which is collected in Xiangxi, Hunan in 2009 and 2010. Several conclusion had been gained: (1) stand mean height, tree number every hectare, soil thickness, age-group, slope orientation, slope situation, natural disaster, elevation, species composition, in these kinds of zoology factors, the factor of stand mean height, tree number every hectare, soil thickness and age-group could affect mean standard tree volume and stand volume every hectare significantly, the others almost had no influence to them. These results could not only be useful to field survey for saving cost, but also insure that the plot data was credible. (2) The stand volume and density model for artificial stand that were 8-10 years management of Alnus cremastogyne in Xiangxi, Hunan had been established, the model formula was . The precision of it was high. The precision was 96.8458%, the relative error mean was 1.1334%, the accuracy test showed that residual error values were equally distributed around the prediction values, and the relative error mean was -1.2156%. (3) The best appropriate density for artificial stand that were 8-10 years management for Alnus cremastogyne in Xiangxi, Hunan was from 800 to 1000 trees every hectare. It was very important to sustainable management for artificial stand management for Alnus cremastogyne in Xiangxi, Hunan.