自然火干扰对新疆喀纳斯旅游区森林景观树种结构的影响

EFFECTS OF NATURAL FIRE DISTURBANCE ON STRUCTURE OF TREE SPECIES IN KANAS TOURISM DISTRICT, XINJIANG, CHINA

自然火干扰是森林生态系统的正常行为,是决定森林物种构成、群落结构和生物多样性的主要因素。该研究将新疆喀纳斯旅游区作为研究对象,把自然火干扰和树种结构作为不可分割的整体,就喀纳斯旅游区树种结构对自然火干扰的响应进行了分析。结果表明,受自然火干扰林分和长期未受干扰林分的树种结构之间存在明显的差异,自然火干扰对阔叶针叶树种比、树种丰富度(Ma)和Shannon-Wiener多样性指数(H′)存在极显著的影响,受自然火干扰后,三者均表现出增大的特征。此外,所调查范围内曾发生8次自然火干扰事件,并且不同时期发生的自然火干扰对以阔叶针叶树种比为特质的季相结构和树种丰富度存在极显著的影响。自然火干扰是影响新疆喀纳斯旅游区季相结构和组成结构的主要因素之一。

Aims Forest fires are widespread disturbance factors in most forest ecosystems. The structure and function of forest ecosystems have a close relationship with fire disturbance. Exploring the effects of natural fire disturbance is important for understanding forest succession. Our objective was to study the effects of fire disturbance on the structure of tree species in the Kanas tourism district to explain the role of natural fire disturbance in forest dynamics. Methods We recorded the height and quantity of each tree species in 78 plots of 30 m × 30 m dimensions in the Kanas tourism district. The dates of fire disturbance were determined by fire scars. Data were analyzed using SPSS software. Important findings Stands with and without natural fire disturbance had different tree structure. Forest seasonal structure and tree composition were affected by natural fire disturbance, and the indexes of tree structure were higher in disturbed plots than that in undisturbed plots. Moreover, the proportion of tree species and tree species richness were significantly different for eight different periods of fire disturbances （p〈0.01）. Fire disturbance was one of the main factors controlling structure of tree species.