Alteration in Forest Soil Biogeochemistry through Coarse Wood Debris in Northeast China

Abstract

Coarse woody debris (CWD) has a strong influence on nutrient dynamics and hinders its availability through fixation. The CWD decaying logs, with two states (three and four) impacting on carbon (C) capture, nutrient dynamics and enzymatic properties, were investigated under and away (50 cm) from the logs in three forest types, i.e., the Picea koraiensis-Abies nephrolepis-Pinus koraiensis forest (PAPF), Betula costata-Pinus koraiensis forest (BPF) and Tilia amurensis-Pinus koraiensis forest (TPF). The results showed that soil organic carbon (OC), nitrogen (N), soil pH, other soil nutrients and enzymatic activity were significantly affected by the forest types, decay class and distance from decaying logs in three forests. The CWD, with decay class IV under CWD, resulted in the optimum OC 64.7 mg g−1, N 6.9 mg g−1 and enzymatic activity in the PAPF forest, and the distance effect was negligible for all the forests. A lower soil pH value of 3.8 was observed at decay class IV in the soil collected from the immediate vicinity of the deadwood. CWD play a key role in decaying logs in forest ecosystems to enhance C and the nutrient budget with the improved enzymatic activity of the soil. It was concluded from this research that CWD is a critical factor in the nutrient cycling process of forest ecosystems that contributes functionally to the forest floor by inducing the spatial heterogeneity of enzymatic activity, C and nutrient turnover.