中国西南地区热带森林演替序列碳动态

热带森林的破坏是全球性问题,我国西双版纳森林覆盖率受砍伐、火烧和短期耕种丢荒后,面积不断减少,取而代之的是大面积的不同演替状态的次生林。次生林演替过程中的碳储量和碳平衡的变化目前还鲜有研究,为了进一步揭示我国西南地区热带森林演替对于碳蓄积的影响,并制定更科学的热带森林经营管理措施,以结构复杂、生物多样和生物量巨大的热带森林为研究对象,并利用3个热带次生林的样地的实测数据,探讨了不同演替状态的热带次生林的碳储量变化,以及森林的净碳蓄积,死亡碳损失和更新碳增长等碳动态规律,分析表明:(1)在森林的演替过程中,森林的胸径分布频度从近正态分布逐渐向小径级的偏态分布发展,也就是随着演替的进展,小径级林木所占的比例越来越高。(2)热带次生林在森林固碳方面发挥着不可忽略的作用。(3)小的干扰,会波及森林的碳动态;大的干扰,如火灾和砍伐,将导致森林的次生演替,对森林的碳动态产生不可逆转的改变。(4)干旱事件是影响凋落物的季节和年间动态的原因,也是短时间尺度上影响碳平衡的一个重要因子。(5)不论原生林还是次生林,大树在生态系统碳动态方面皆扮演着重要的角色,因此本研究推荐注重大树的研究。

Carbon dynamic of a tropical forest succession series in Southwest China

The destruction of tropical forests is a global problem. After being felled, burned and farmed for a short time, the forest coverage of Xishuangbanna in China has been gradually reduced and replaced by a large area of secondary forests in different succession states. However, the changes of carbon stock and carbon balance in secondary forests succession have been rarely studied. In order to further reveal the tropical forest succession for the influence of carbon accumulation in Southwest China,and to formulate a more scientific management measures for tropical forest management, taking tropical forest with compllicated structure, biodiversity and huge biomass as the research object, and using the measured data of three tropical secondary forest samples,the change of carbon reserve,net carbon accumulation,dead carbon loss, carbon sequestration, and other carbon dynamics of tropical secondary forest in different succession states were discussed. The results indicated that: *1) In the process of forest succession, the distribution frequency of forest diameter at breast height (DBH) gradually develops from the near-normal distribution to the skewness distribution of footpath, that is, with the progress of forest succession, the proportion of footpath trees became higher and higher. (2) The tropical secondary forests played an important role in carbon sequestration. (3) Small disturbances affected the carbon dynamics of the forest. Large disturbances, such as fire and logging, would lead to secondary succession of forests, with irreversible changes in the carbon dynamics of forests. (4) Drought events were the causes that affected the seasonal and inter-annual dynamics of litters, and were also an important factor affecting the carbon balance on a short time scale. (5) Large trees should be well studied for its significant important role in forest carbon balance.