Litterfall, litter decomposition, and carbon storage of Pinus densiflora and Quercus variabilis stands in South Korea

The quantification of carbon (C) storage of different stand types is a key component for understanding forest C cycles and potential climate change. This study evaluated the effects of stand types on litterfall, litter decomposition, and forest C storage in Pinus densiflora S. et Z. and Quercus variabilis Blume stands in southern Korea. The aboveground C storage by tree biomass was not affected (P > 0.05) by stand types (P. densiflora: 79.49 Mg C ha^–1; Q. variabilis: 96.37 Mg C ha^–1). However, total C inputs by litterfall were significantly higher for the P. densiflora (4,473 kg C ha–1 year–1) than for the Q. variabilis (2,633 kg C ha–1 year^–1) stands. Organic C over litter decomposition processes was more rapidly mineralized in the leaf litter of Q. variabilis than in needle litter of P. densiflora, but C storage on the forest floor was not affected by different stand types. Total soil C storage was not significantly different between the Q. variabilis (55.71 Mg C ha^–1) and P. densiflora (80.49 Mg C ha–1), whereas the C concentrations at each soil depth were significantly higher in the P. densiflora than in the Q. variabilis stands, except for the subsurface depth (30–50 cm). These results indicate that the distribution of C storage in P. densiflora and Q. variabilis stands is less susceptible to interspecific differences, such as litterfall inputs and decomposition rates.