北京山地不同密度侧柏人工林林分生长及灌草多样性研究

目的]研究不同密度侧柏人工林林分生长及灌草多样性.方法]以北京市八达岭石佛寺浅石山区5种不同密度(1 500、2 000、2 550、2 700、2 900 株/hm2)侧柏人工纯林为研究对象,对其生长状况及灌草多样性进行初步研究.结果]林分生长因子排序为:树高＞冠幅＞胸径＞枝下高.灌草物种数目均随林分密度增大先增加而后减少,灌草各多样性指数值和总和均随林分密度增加先增大后减小,在密度为2 550株/hm2时达最大值；灌木Menhinick值变化范围为0.40～1.49、草本Menhinick值在1.05 ～1.51、灌草Simpson指数分别在0.66 ～0.82和0.65 ～0.79、灌草Shannon-wiener值分别在2.68 ～ 5.66和3.40 ～4.95、灌木Jsu值在1.29 ～2.46、草本Jsw值在1.64～2.38.结论]密度为2 550株/hm2的林分生长最好、灌草多样性指数值最大,林分最优.

Study on Forest Growth and Shrub-grass Diversity of Platycladus Orientalis Plantations in the Different Densities in Mountain of Beijing

Objective] Forest growth and shrub-grass diversity of Platycladus Orientalis plantations were studied.Method] This article selects Beijing Badaling shifosi shallow mountain area 5 different densities(1 500,2 000,2 550,2 700,2 900 plants/hm2) artificial pure forest of platycladus orientalis for the object.The growth and diversity of shrub-grass were studied.Result] The order of stand growth factor is tree height>grown>DBH>clear length.The shrub-grass number first increase,then reduce with stand density increase.The Menhinick value of shrub ranges from 0.40 to 1.49,and herbal Menhinick value ranges from 1.05 to 1.51.Simpson index of shrub ranges from 0.66 to 0.82,and grass Simpson index ranges from 0.65 to 0.79.Shannon-wiener values of shrub-grass are respectively 2.68-5.66 and 3.40-4.95.Jsw values of shrub and herbal are respectively 1.29-2.46 and 1.64-2.38.Conclusion]The best density of stand growth is 2 550/hm2,on this condition,shrub and grass diversity index value is the biggest,the stand growth is optimal.