Effects of Different Disturbance Intensities on Soil Physical Properties of Castanopsis Secondary Forest

This paper reports the changes in soil physical properties of Castanopsis secondary forests under different disturbance intensities with four levels:BCK treatment (no selection cutting),GTN treatment (selection cutting of small trees within 20% of the total number of trees,with all the harvested material returned to the forest field and covered on the ground surface,hereinafter the same),GTT treatment (selection cutting of 20~30%) and GTF treatment (selection cutting of 30~40%).The results were as followes:there was a significant difference in soil bulk weight between GTF treatment and BCK treatment in 0~20 cm soil layer (P＜0.05),the difference between non-capillary pore space and capillary pore space was not significant,and there was a significant difference in total porosity (P＜0.05);the difference between field water holding capacity and saturated water holding capacity was less than 1%.The mechanical composition of the soil was not affected,and the content of water stabilizing agglomerate did not reach a significant level,but GTF treatment instead increased by 2.97% compared with BCK treatment.In other treatments,the differences in soil physical properties among the same soil layer were becoming smaller and tended to be weaker.The intensity of selection cutting in the range of 30% did not lead to significant changes between soil physical properties and those of the Castanopsis secondary forests that were maintained in their original state.When the intensity was more than 30%,the effect was significant on several soil physical properties (0~20 cm bulk weight and total porosity).In order to promote the growth of castanopsis secondary forest and enhance their ecological functions,moderate tending cutting can be feasible.