黄土高原刺槐林间伐改造研究

通过对 9年生刺槐 (Robiniapseudoacacia)林以 3种不同保留密度进行间伐改造 ,并对其林内光照、温度和土壤水分环境因子以及林下植被层生物多样性、生产力和林冠层林木的生长情况与原林分进行对比分析 .结果表明 ,间伐改造能改善林木及林下植被层生长发育的环境条件 ,促进林下植被层生物多样性和生物产量的提高 ,增加林木的生产能力 .间伐保留密度达到 1110株·hm-2 时 ,在整个生长季 ,林地土壤水分比原林分提高约 40 %,不仅林下植被层的生物多样性和生物量有大幅度提高 ,而且林冠层林木的生产力达到较高水平 ;如果继续加大间伐强度 ,林下植被层和林木个体的生长已达到最大极限 ,将不再提高 .因此 ,1110株·hm-2 左右的保留密度是可考虑的间伐强度 .

Study on thinning to Robinia pseudoacacia forest on the Loess Plateau.

Radiation, temperature and soil moisture in the forests, the biodiversity and productivity of understory plants, and the growth of trees among 3 thinned 9-year-old Robinia pseudoacacia forests (735 individuals.hm-2, 1110 individuals.hm-2, and 1480 individuals.hm-2) and non-thinning forest (2220 individuals.hm-2) were analyzed comparatively. The results showed that thinning could improve growing condition of trees and understory plants, so that the biodiversity and biomass of understory plants and producing ability of trees were increased. When the remaining density was 1110 individuals.hm-2, the soil moisture was increased by 40% comparing with the non-thinning forest in whole growing seasons. The biodiversity and biomass of understory plants and productivity of trees were increased significantly. If the thinning intensity were increased continuously, the growth of understory plants and trees would reach the maximum and not increase any longer. Therefore, the thinning intensity with remaining density of 1110 individuals.hm-2 was optimum for black locust forest in this region.