TRIPLEX model testing and application for predicting forest growth and biomass production in the subtropical forest zone of Chinaʹs Zhejiang Province

This study has analyzed TRIPLEX1.0 by applying the model to the subtropical forest regions in Zhejiang Province, southeastern China. The main objective was to test the process-based hybrid model TRIPLEX1.0 in simulating density, tree height (H), diameter at breast height (DBH), litter pool and biomass using forest growth and yield data collected from three forest types: subtropical evergreen broad-leaved, coniferous broad-leaved mixed and warm temperate pine (Pinus massoniana Lamb.) forests. The results show that simulated density, H, DBH, litter pool, aboveground and total biomass are consistent with observed data collected through Zhejiang Province, suggesting that the TRIPLEX1.0 model is capable in simulating forest growth and biomass dynamics of subtropical forest ecosystems. The coefficient of determination (r2) between simulated values and yield measurements show a 0.91 variability for density, 0.86 for DBH, 0.83 for H, 0.89 for aboveground biomass and 0.91 for total biomass (except for litter pool that showed a 0.54 variability). The independent validations obtained by utilizing TRIPLEX1.0 demonstrate that the model offers competency while providing confidence when applying its ability to extrapolate outcomes at regional scales and its ability to withstand rigorous testing for simulating carbon storage in subtropical forest ecosystems.