Climate-sensitive diameter distribution models of larch plantations in north and northeast China

Tree diameter distribution models are important tools for forest management decision making. Climate change will affect tree growth and thus diameter distribution. However, there is lack of diameter distribution models describing the effects of climate. The paper developed a climate-sensitive diameter distribution model based on 193 sample plots of larch plantations in north and northeast China. Weibull distribution model was modified by a compatible simultaneous system and the percentile-based parameter recovery method with the inclusion of climate variables. The results showed that showed BIO10 (mean temperature of warmest quarter) and BIO14 (precipitation of driest month) are key climatic factors which shape the diameter distribution of Larch plantations. Compared with parameter estimation models without climate variables, the adjusted R2 was improved (5.03% for β, and 3.32 % for γ), RMSE (73.12% for β, and 2.89 % for γ)and TRE (92.16% for β, and 5.57% for γ) decreased. The models with climate factors are significantly different from that without climate factors by F test. The models with climate factors are improved and could be applied for diameter distribution projection under future climate change.