Model simulation of soil carbon dynamics with stand development in Japanese cedar (Cryptomeria japonica) plantations

Soil carbon cycling in Japanese cedar plantations after clear-cutting over time was calculated with and without consideration of plantation management (pruning and thinning) using a mathematical model. The model employed a daily time step and used daily air temperature and observed precipitation near the plantations. The results of these calculations of above-ground biomass, carbon flow and accumulation were compared with the field observations reported by Shutou and Nakane (Ecol Res 19:233-244, 2004) observed in the Hiroshima prefecture. For example, the carbon accumulation and total soil respiration rate calculated with the inclusion of plantation management for a 60-year-old stand were 104 and 4.8 t C ha(-1) year(-1), compared with a field observation of 110 and 4.5 t C ha(-1) year(-1), respectively. The results calculated for carbon flow and accumulation were not significantly different from the field observations, assessed using one-way analysis of variance (P > 0.05), and the mean relative errors were very small (e.g., the maximum was 0.05). Consequently, it is suggested that the dynamics of carbon cycling following clear-cutting of a Japanese cedar plantation can be simulated realistically using these calculations with and without consideration of plantation management. Moreover, it is possible that the calculation without consideration of plantation management can yield the change of carbon cycling over time, even if the history of forest management in the plantations is unknown. It is expected that this study will contribute to the development of a more versatile model.