秦岭南坡锐齿栎次生林空间结构特征分析

该研究采用坐标定位方法对秦岭南坡不同坡向锐齿栎次生林样地内胸径DBH≥5cm的乔木进行调查,记录树种名称、坐标、胸径、高度、冠幅、生长状况等因子,运用角尺度、大小比数和混交度3个指数分析不同坡向锐齿栎次生林的空间结构,探寻不同坡向锐齿栎林空间结构的形成和差异。结果显示:(1)调查样地内物种多样性丰富,锐齿栎重要值最大,长势良好,占据主要生态空间。(2)两种坡向中,角尺度取值为0.5的个体数均过半,表明随机分布是锐齿栎次生林的主要分布方式。(3)优势木、亚优势木、中庸木、劣态木和绝对劣态木所占比重均为20%左右,表明林木大小差异不明显,在空间结构单元中,林木较稳定,阳坡优势木个体数高于阴坡。(4)两种坡向中,混交度取值大于0.5林木个体分别为84%和73%,表明多数林木个体处于中度、强度和极强度混交状态。研究表明,秦岭南坡锐齿栎次生林聚集度不高、混交良好、分化程度较高,锐齿栎种群优势度明显,林分整体暂时处于相对稳定状态。

Spatial Structure Characteristics of Quercus aliena var.acuteserrata Secondary Forest on South Slope of Qinling Mountains

This paper analyzed the spatial structure of two Quercus aliena var.acuteserrata secondary forests between shady slope and sunny slope by the parameters(uniform angel index,mingling degree,neighborhood comparison) on south slope of Qinling Mountains.The result showed that:(1)there was abundant species diversity of Q.aliena var.acuteserrata community.Q.aliena var.acuteserrata had the biggest importance value,also in a principal ecological space.(2)The main spatial structure of Q.aliena var.acuteserrata was random distribution because of the number of uniform angel index higher than 0.5 of individual tree over 50% between the two different slopes.(3)The proportion of five different tree differentiation classes are all about 20%.There was no difference among the differentiation classes of Q.aliena var.acuteserrata community.The number of dominant tree on the sunny slope was higher than that on the shady slope.(4)The mingling of trees mostly presented moderate or high,based on the proportion was 84% and 73% of mingling over 0.5 on the sunny slope and the shady slope.Above all,Q.aliena var.acuteserrata secondary forest had low aggregation degree,good mingling degree,higher differentiation,significantly population abundance,and in a relatively stable state.