气候变暖和降水格局改变对森林植物物候具有重要影响。作为森林生态系统的重要组成，亚热带森林的植物物候对气候变化如何响应尚不清楚。基于我国南亚热带地区每十年升温0.2℃，以及干季更干和湿季更湿的气候变化趋势，本项目拟以我国南亚热带常绿阔叶林主要优势树种为研究对象，结合幼树“增温-降水格局改变”控制实验、自然林“降水格局改变”控制实验以及自然林长期叶物候和同期温度及降水观测数据，明确增温和降水格局改变分别对南亚热带春季叶物候的影响，揭示这两种气候变化因子对春季叶物候改变是否存在交互作用，阐明亚热带春季叶物候对于增温和降水格局改变的响应机制。在此基础上，通过比较现有的不同物候模型筛选适合亚热带的模型，并尝试在所选模型中加入降水因子优化模型，最终预测亚热带春季叶物候对未来气候变化的响应及机制。本研究有助于认识亚热带森林树木对气候变化的响应，为森林生态系统结构和功能变化预测和科学经营提供理论依据。

Climate warming and changes in precipitation pattern can alter vegetation phenology in forests. In subtropical forests of China, the annual mean temperature increased 0.2℃ per decade, accompanied by altered precipitation, i.e., reduced dry-season rainfall, increased wet-season rainfall and unchanged total annual precipitation. However, it is unclear how these climate changes affect the phenology of subtropical forests. This project investigates the influence of warming and precipitation alteration on the spring leaf phenology of dominant tree species in subtropical forests, using spring leaf phenology records from "warming-precipitation alteration" experiment of seedlings and "precipitation alteration" field experiment, combined with the long-term in situ spring leaf phenology data. On this basis, the optimal phenology model for subtropical spring leaf phenology is selected among the models that have been widely used for spring phenology of boreal and temperate trees. The selected model, after being incorporated precipitation to improve its accuracy, is used to predict the spring leaf phenology of subtropical trees under future climate change scenarios. This study helps to understand the responses of subtropical trees to climate change, and provides a theoretical basis for predicting changes in forest ecosystem structure and functions and sustainable management.