Comparison of soil CO2 efflux rates in Larix leptolepis, Pinus densiflora and P. rigitaeda plantations in southern Korea

Abstract

This study compared soil CO2 efflux rates in three adjacent coniferous plantations consisting of larch (Larix leptolepis Gordon), red pine (Pinus densiflora S. et Z.) and rigitaeda pine (P. rigitaeda: P. rigida Mill x P. taeda L.) species planted in the same year (1963). Soil CO2 efflux, litter fall carbon (C) and root decomposition rates were measured with soil environmental factors for two years. The mean annual soil CO2 efflux rates (g CO2 m(-2) hour(-1)) were the highest in rigitaeda pine (0.30), followed by red pine (0.27) and larch (0.24) plantations. An exponential regression of the CO2 efflux rates against their corresponding soil temperatures showed a significant (P < 0.05) relationship (red pine R-2 = 0.69; rigitaeda pine R-2 = 0.67; larch R-2 = 0.63). The soil CO2 efflux rates were negatively correlated with soil pH, but the soil water and soil organic C content were not significantly correlated with the CO2 efflux rates. Soil CO2-C efflux rates were correlated by litter fall C inputs in the larch and red pine plantations, and the decomposition rates of 5-10 mm diameter roots in the larch plantation. This result is useful in understanding potential responses of soil CO2 efflux rates with changes in stand and soil environmental factors induced by different tree species.