Effect of thinning on carbon storage in soil, forest floor and coarse woody debris of Pinus densiflora stands with different stand ages in Gangwon-do, central Korea

This study was conducted to investigate effects of thinning on carbon (C) storage of soil, forest floor and coarse woody debris (CWD) in Pinus densiflora stands, central Korea. Two study stands (25- and 55-year-old stands) were located in P. densiflora forests of Gangwon-do and thinned in 2008. Each stand was divided into three plots by different thinning intensities based on stand density: no thinning (control, 0%), moderate thinning (M, 30%), and heavy thinning (H, 50%) in the 25-year-old stand and no thinning (control, 0%), light thinning (L, 20%), and moderate thinning (M, 30%) in the 55-year-old stand. We measured C storage of 0–30 cm depth soil, forest floor and CWD in 2009. Total C storage (t C ha⁻¹) of soil, forest floor and CWD in two thinned plots was significantly higher than that in the control plot only in the 55-year-old stand: 66.4 for control, <84.2 for L, <117.9 for M. On the other hand, total C storage in the 25-year-old stand did not show a consistent tendency among thinning intensities. We speculated that 1 year was too short to detect any consistent changes in total C storage of soil, forest floor and CWD by thinning, and long-term observation would be needed.