冀北山地山杨白桦混交林林分空间结构研究

为了探究山杨和白桦混交林的林分空间结构,运用林分结构参数混交度、角尺度、大小比数和直径分布指标,对木兰围场次生山杨、白桦混交林的群落结构特征进行了研究.结果表明:山杨、白桦次生混交林的树种组成很丰富,群落中当地树种占绝对主导地位;从水平结构来说,林分平均角尺度为0.502,群落呈现出随机分布格局;群落的树种隔离度很高,平均混交度为0.618,但其主要树种山杨和白桦的混交度最低为0.26和0.39;群落所有乔木树种以胸径作为大小比数的指标的优势树种排列为:落叶松>黑桦>白桦>蒙古栎>山杨>棘皮桦>花楸>云杉>黄桦>油松>五角枫;林分整体处于结构稳定发展状态.

Tree structure characteristic of mixed Populus davidiana and Betula platyphlla plantation in north mountain of Hebei Province

The stand structure characteristics of secondary forestry of Populus davidiana and Betula platyphlla in Mulan forest farm of Hebei province was analyzed using spatial structure parameters of angle index,mingling neighborhood comparison and diameter distribution.The result showed that the secondary forestry had high tree species diversity and tree species composition was abundant.There were also many common tree species.The level structure showed the angle value was 0.502,and the pattern of horizontal distribution was random.The tree species segregation was higher and the average value of mingling was 0.618,but the main lection Populus davidiang and Betula platyphlla had the lowest mingling 0.26 and 0.39.the order of tree species neighborhood comparison compared with breast height diameter was follow:Larin gmelinil>Betula dahurica> Betula platyphlla >Quercus mongolica> Populus davidiana >Betula dahurica>Mountain ash>Picea asperata>Betula alleghaniensis>Pinus tabulaeformis>Acer mono.