抛荒毛竹林珍贵树种化改造对林地温室气体排放与碳汇功能的影响机制

毛竹生长速度快，固碳能力强，在减缓全球变暖中发挥独特作用。然而近年来毛竹价格下降和劳动力成本上升，放弃经营的抛荒竹林面积不断增加。毛竹林抛荒后景观严重受损、火灾风险增加、林地浪费，还可能导致固碳能力不断下降，竹农和政府都有强烈意愿将其进行珍贵树种化改造，寻求合理的改造模式以达到改善林种结构、提升生态服务和碳汇功能的目的。但是，珍贵树种化改造抛荒毛竹林后对竹林碳汇功能的影响及其机制尚不清楚。本项目拟通过抛荒毛竹林皆伐和3种间伐强度的带状珍贵树种化改造的受控实验，研究改造对林分碳储量、土壤有机碳储量与温室气体（CO2、CH4和N2O）排放的影响，并从土壤理化性质、酶、微生物和植物生长等角度揭示改造对温室气体通量和植被固碳的影响机制，探讨改造对抛荒林地生产力和固碳功能的潜力。研究结果可为全面认识抛荒毛竹林珍贵树种化改造的作用提供科学依据，为促进我国竹产业的转型升级和珍贵树种发展提供新视角和参考。

Moso bamboo (Phyllostachys edulis) forests play a unique role in mitigating global climate change because of its rapid growth and strong carbon fixation capacity. However, with the decreasing price of bamboo and increasing labor cost, the abandoned area of moso bamboo forests has being increased in recent years. These abandoned moso bamboo forests are bringing about severe problems, such as decreasing landscape function, increasing fire risk, wasting forest land, decreasing carbon fixation ability and etc. Therefore, both bamboo farmers and government have a strong desire to convert them into valuable tree species forests and to explore reasonable conversion modes, hoping to achieve the goal of improving the forest species structure, ecosystem service and carbon fixtation. However, the effects and mechanism on stand carbon sequestration of stand converting from abandoned moso bamboo forests to valuable species forests still remain unclear. In this project, we intend to explore the changes in vegetation carbon storage, soil organic carbon storage and soil greenhouse gas (CO2, CH4 and N2O) emission during stand converting from abandoned moso bamboo forests to valuable tree species forests under four types of typical stand transformation modes (clear-cut and three kinds of thinning intensities in strips following with planting valuable tree species seedlings). Meanwhile, it is expected to reveal the influencing mechanism on greenhouse gas flux and vegetation carbon sequestration, forest productivity and carbon sequestration by stand conversion based on the dynamics of soil physicochemical properties, enzymes, microorganisms and plant growth. This study will provide the comprehensive scientific understanding of the effects on stand converting from abandoned moso bamboo forests to valuable tree species forests, and give a new perspective for the transformation and upgrading of bamboo industry and the development of valuable tree species resources in China.