祁连山青海云杉林群落结构特征分析

Analysis on Community Structure of Picea crassifolia Forests in the Qilian Mountains

通过区域尺度,以祁连山国家自然保护区东段的哈溪林场、中段的西水林场和西段的祁丰林场3个典型分布区的青海云杉纯林为研究对象,以设立的典型临时样方调查材料为研究基础,对祁连山青海云杉的群落结构特征进行了分析,包括青海云杉林成层结构、胸径结构、树高结构和冠幅结构的静态分布,并对胸径、树高和冠幅三者之间的相互关系进行了曲线拟合。结果表明:①青海云杉林群落成层现象明显,可划分为乔木层、灌木层、草本层和苔藓层,祁连山东、中、西段青海云杉林乔木层结构参数与林下灌木层、草本层结构参数在一定程度上呈负相关,祁连山中段苔藓较为发达;②祁连山东段青海云杉胸径结构呈"间歇"型,中段呈"倒J"型,西段呈"单峰"型,同时树高和冠幅结构表明,青海云杉林普遍存在更新不良的问题;③对祁连山不同研究区域青海云杉个体及3个调查区域所有个体的胸径、树高与冠幅进行曲线拟合,发现三者之间相关显著,均可用乘幂曲线模型Y=aXb进行较好的描述(P<0.01)。上述结论可为祁连山青海云杉的可持续经营、群落恢复和抚育管理提供科学依据。

In this paper, the features of Picea crassifolia pure forests at regional scale were analyzed by selecting three typical P. crassifolia forests in the Haxi, Xishui and Qifeng forest centers in the eastern, middle and western parts of the Qilian Mountains in China. The community structure characteristics, including the layer structure, DBH, height structure and static distribution of crown diameter structure of P. crassifolia forests in the designed temporary plots, were investigated. The regression correlations among these three indexes（ DBH, height and crown diameter） were developed. The results are as follows ： （ 1 ） Four layers, i.e. the arborous, shrub, herb and moss layers, could be observed. To some extent, the structure characters of arborous layer were negatively correlated with that of shrub and herb layers. Furthermore, moss in the middle part of the Qilian Mountains developed well; （2） The DBH of P. crassifolia in eastern part of the Qilian Mountains was in an ＂intermittent＂ type, and it was in a ＂reverse J＂ type in the middle part and a ＂unimodal＂ type in the western part. Moreover, the analyzed result of structure of the tree height and crown diameter showed that the regeneration of P. crassifolia was unhealthy in the study area; （3） In the different regions and sample plots, DBH, height and crown diameter of P. crassifolia were significantly correlated with each other, the regression model Y = aX^b（P 〈 0.01 ） could be used to depict their cor- relations. It is believed that these results can provide the theoretical basis for sustainable management, community regeneration and tending management of P. crassifolia forest in the Qilian Mountains.