油松人工林密度与养分循环关系的研究

该文以北京市八达岭林场37年生油松人工林为研究对象，以每木检尺、树干解析和化学分析的数据为基础，对不同密度类型（900、1 500、2 000株/hm2林分Ca、K、Mg、Cu、Fe、Mn、P、Zn 8种养分元素的循环状况进行分析比较. 结果表明:密度为1 500株/hm2的林分，其林木各器官中的养分积累量、林分养分的吸收和利用效率均处于较高水平. 因此得出结论，在八达岭地区最合理的油松人工林成林密度应是1 500株/hm2左右. 

Nutrient element cycling and density effect in Pinus tabulaeformi plantations

Based on the method of tally stem analysis and chemical analysis, the accumulated contents and biological cycle of eight nutrient elements (Ca, K, Mg, Cu, Fe, Mn, P, Zn) in tree stems from three 37 years old experimental Chinese pine plantations with different density (900, 1 500, 2 000 trees/hm2) at the Badaling Forestry Centre in Beijing, were investigated. Results showed that the plantation with 1 500 trees/hm2 possessed the largest amount of accumulated nutrient elements and absorption as well as the highest efficiency in the use of nutrient elements. It suggests that the most rational density of Chinese pine plantations in the Badaling district is 1 500 trees/hm2.