Effects of light-felling intensity on hydrological effects of litter in Korean pine forests by 'planting conifer and preserving broadleaved tree' in Xiaoxing'an Mountains of China.

Abstract

To understand the effects of 'planting conifer and preserving broadleaved tree' and light-felling on the hydrological effects of litter layer during the restoration of the climax vegetation broad-leaved Korean pine forest in temperate zone of Northeast China, we measured litter accumulation, water holding process of litter, and maximum holding water, maximum blocking and effective blocking amount of litter layers using sample survey method and indoor immersion method in three forests (aspen-Korean pine forests, white birch-Korean pine forest, and Mongolian oak-Korean pine forest) under different light-felling intensity (control, C; low light-felling, L; moderate light-felling, M; heavy light-felling, H) in Xiaoxing'an Mountains. The results showed that the intensity of light-felling had different effects on litter accumulation (7.32 to 15.58 t·hm-2) in three forest types. L, M and H significantly enhanced litter accumulation by 24.3%-34.6% in the Mongolian oak-Korean pine forest, L and M enhance it by 15.3%-19.3% in aspen-Korean pine forest, and H enhance it by 27.1% in white birch-Korean pine forest. Water holding capacity (W) and water absorption rate (V) of the undecomposed layer and the semi-decomposed layer of the litter were in accordance with the relationship between the soaking time (t): W=alnt+b (R2>0.908), V=ktn (R2≥0.999). The intensity of light-felling (except H in aspen-Korean pine forests) increased the maximum water holding capacity (17.86-45.12 t·hm-2), maximum interception capacity (16.10-34.19 t·hm-2) and effective interception capacity (13.42-27.42 t·hm-2) of litter by 30.1%-74.8%, 27.4%-83.6% and 26.7%-86.0%, respectively, while changed the differences of effective blocking amount of litters among forest types. Therefore, light-felling significantly enhanced the hydro-ecological function of litter layers in the medium-term broad-leaved Korean pine forests by 'planting conifer and preserving broadleaved tree'. The low, moderate, and heavy light-felling was best one for the Mongolian oak-Korean pine forest, the aspen-Korean pine forest, and the white birch-Korean pine forest, respectively.