摘要
Investigations on charcoal in the soil, fire-scarred trees, stand composition, forest structure as well as regeneration status were carried out in the natural broad-leaved/Korean pine (Pinus koraiensis) forest after fire disturbance at Liangshui Nature Reserve on the mid-north of Xiaoxingan Mountains from 1990 to 1992, and the ecological effects of fire disturbance on the formation and succession of this kind of forest were analyzed according to the survey results. The average depth of charcoal in the soil was related to the timing of the fire. According to the characteristic of fire-scarred trees, the dynamic map of the fire behavior was drawn onto the topographic map. It showed that the dimension and extent of the fire disturbance was closely related with site conditions. Fire disturbance only led to a significant difference in stand composition and diameter class structure for the stands at different locations, rather than completely destroying the forest. After fire disturbance, the horizontal community structure was a mosaic of different patches, which were made up of different deciduous species or different sizes of Korean pines, and the succession trend of each patch was also different. In the sites with the heavy fire disturbance, the intolerant hardwood species were dominant, and there were a large number of regenerative Korean pine saplings under the canopy. In the moderate -disturbed sites, the tolerant hardwood species were dominant, and a small number of large size Korean pines still survived. In the light-disturbed sites, large size Korean pines were dominant.
分别对小兴安岭凉水自然保护区天然红松林土壤中木炭、火烧木疤痕和林分组成进行了调查,探讨了火干扰对森林形成和演替的生态作用。在不同年代发生火干扰的林分中,抽样挖掘木炭,测量木炭块的大小和分布深度,记录各林分结构特征和红松更新状况,并根据树木火疤圆盘确定火干扰年代。本研究选择了50hm2火干扰林分,对火烧疤痕木进行详细调查,并在其中设置样地,调查各样地林分组成和红松径阶结构。结果表明:Ⅰ.不同火干扰年代的林分,土壤中的木炭平均深度与火干扰发生的时间关系密切。Ⅱ.根据火干扰林分中火烧木疤痕的调查,绘制火行为动态图,证明火烧方向和火干扰程度与立地条件关系密切。Ⅲ.火干扰并未完全地破坏森林,仅仅是导致林分中不同地点上林分组成和红松径阶结构的差异明显。火干扰后,整个林分的水平结构是一个由不同树种组成和不同红松径阶结构的树木群团构成的镶嵌体,各树木群团的演替趋势不同。在火干扰较重的地点,阳性阔叶树种占优势,阔叶树下更新有大量的红松小树;在火干扰较轻的地点,耐阴性阔叶树种占优势,并有少量大径阶红松;在火干扰轻微的地点,大径阶的红松占优势。图6表2参19。
基金
Doctor Foundation of Ministry of Education (2000002716)
