树木年轮在干扰历史重建中的应用

The application of tree-ring on forest disturbance history reconstruction

干扰是影响森林生态系统结构和功能的重要因子,重建森林群落干扰历史可以掌握干扰发生的机制和规律,对森林经营有重要意义。年轮记载了树木逐年的生长历史,利用年轮可以重建不同尺度上干扰的时空格局,具有重建历史长、定年准确和材料容易获得的优点,是森林动态历史研究不可替代的资料。干扰对树木个体的影响可以分为伤害干扰和生长干扰两种类型。不同类型干扰的特点和对树木的生长影响不同所以重建方法也不同,对树干造成直接伤害的干扰可以利用树干的疤痕重建,如火灾和泥石流等;生长干扰对树木的生长势造成影响,可以通过识别年轮中的生长抑制和释放发生和持续时间来确定干扰的时间和强度。但是对破坏性的干扰事件要通过群落中个体的建成时间高峰来判断。欧洲和北美地区利用树木年轮重建森林干扰历史的研究已经很广泛,主要包括火灾、虫灾、地质灾害和气象灾害等干扰类型,在中国利用年轮重建群落干扰的研究还处于起步阶段。探讨了应用树木年轮重建不同森林干扰事件的方法,总结了不同的重建方法和干扰重建取得的进展,并指出了以后研究的方向,为以后的干扰重建提供了参考。

Disturbances significantly influent the species composition, age structure and functions of forest ecosystem, and therefore play important roles in forest regeneration, community succession, and maintenance of species diversity and are a base for the structure and function development of forest ecosystem. Reconstruction of the disturbance occurrence in time and space could help us to know the pattern and mechanism of disturbance occurrence and provide reference for predicting future disturbance occurrence, which is an important for understanding forest community dynamics and executing forest managements. Tree rings, as a natural recorder of the tree growth process, could be used to reconstruct the spatial and temporal patterns of forest disturbance history in different scales, therefore tree rings were an unreplaced material for reconstructing the forest dynamic history. Impacts of disturbance on individual trees can be divided into direct injury and growth interference. Methods reconstructing disturbance history vary depending on different disturbance types. For example, stem scars could be used to reconstruct the times and span of disturbances, such as fires and landslides, which caused direct injury to stems. Growth disturbance, such as the insects outbreak, changes the normal growth, and the disturbance time and intensity can be determined through the abnormal growth phenomena including suppression and release.. However, destructive disturbance in the forest communities might destroy most of trees, and therefore the disturbance time can be only determined by using the trees recruitment time peak. There are many studies carried out in Europe and north American by using tree rings to reconstruct forest disturbance history and the dynamic of forest ecosystem,such as fire, insects outbreaks, geological and meteorological disasters. However in China, the study of dendroceology is at initial stage, and few research focuses on the relationship between tree rings and the forest disturbance. In this paper we review the applications of tree rings in reconstructing forest disturbances, and summarize the reconstruction methods and the research progress to provide reference for future reconstruction of disturbances.