桉树相思混交林郁闭度和立地类型对其林下套种土沉香幼树生长的影响

Effects of Canopy Density and Site Conditions of Mixed Forest of Eucalyptus and Acacia on the Growth of Aquilaria sinensis Saplings Interplanted Under the Mixed Forest

以深圳田头山市级自然保护区桉树相思混交林下套种土沉香为研究对象,调查4种郁闭度处理(0~<0.2、0.2~<0.4、0.4~<0.6、0.6~<0.8)与4种立地类型(Ⅰ类、Ⅱ类、Ⅲ类、Ⅳ类)林下套种土沉香生长指标,分析不同郁闭度与立地类型对土沉香生长状况和保存率的影响。结果表明:土沉香在中、下坡位长势优于上坡位,且随着郁闭度增大而呈现先增大后减小的趋势。对林下套种土沉香生长指标进行隶属度函数分析及综合评价,郁闭度在0.2~<0.4,土层深厚、坡度较缓且阳坡较适宜土沉香生长。

With the study object of interplanted Aquilaria sinensis under mixed forest of Eucalyptus and Acacia in Tiantoushan Municipal Nature Reserve in Shenzhen,four degrees of canopy density(0-0.2,0.2-0.4,0.4-0.6,0.6-0.8)and four types of site conditions(Ⅰ,Ⅱ,Ⅲ,Ⅳ)were set up to investigate the growth indexes of Aquilaria sinensis interplanted under the mixed forest and analyze the effects of different degrees of canopy and site conditions on the growth and rate of retention of Aquilaria sinensis.The results showed that the growth of Aquilaria sinensis in the middle and lower slope was better than that in the uphill slope and tended to increase first and then decrease with the increase of canopy density.Through the membership function analysis and comprehensive evaluation of the growth index of Aquilaria sinensis,the canopy density is in the range of 0.2-0.4 with the deep soil layer on the gentle and sunny slope,which is more suitable for the growth of Aquilaria sinensis.