冀北山区华北落叶松桦木混交林空间结构分析

SPATIAL STRUCTURE AND POINT PATTERN ANALYSIS OF Larix Principis-rupprechtii mayr AND Betula Spp. MIXED FOREST IN NORTHERN HEBEI MOUNTAIN

本研究以河北围场县北沟林场的典型林分类型-华北落叶松桦木混交林-为研究对象,通过混交度、大小比数和角尺度以及点格局方法分析了林分的空间结构特征。结果表明:此林分中主要有8个种群,华北落叶松(Lar-ix principis-rupprechtii Mayr)和桦木(白桦(Betula platyphylla Suk)和黑桦(Betula dahurica Pall.))在数量和断面积比例占优势,是林分中的优势树种;华北落叶松的平均混交度为0.52,混交程度高,主要以中度混交和强度混交为主,桦木的平均混交度为0.56以中度混交为主,其他伴生树种的混交程度较高;林分中的华北落叶松和桦木的相对优势度较高,以中庸木和优势木为主,分别占63%和66%,其它树种的优势度不明显;该林分的空间分布格局为聚集分布,但聚集程度不明显,偏向随机,两种格局分析结果相近。

Study by the typical forest type-Larix principis-rupprechtii Mayr and Betula spp.mixed fores-in Weichang of Hebei,and by using the uniform angle index,neighborhood comparison,mingling degree and point pattern analysis,analyzed the spatial structural characteristics of Larch and birch mixed forest.The results showed that：There were 8 populations in the tree layer of the forest,among which Larix principis-rupprechtii Mayr and Betula spp.had the obvious advantage in population density and basal area,are the dominant tree species.The average mingling degree of the Larix principis-rupprechtii Mayr forest was 0.52,suggesting the high mingling degree of stands.The average mingling degree of the Betula spp.was 0.56,suggesting the middle mingling degree of stands.The accompanying species were generally well-mixed.In the spatial structural units,Larix principis-rupprechtii Mayr and Betula spp.populations were mainly of dominant,sub-dominant,and intermediate trees,accounting for 63% and 66% of the total plants of the populations,while the advantages of other populations were not obvious.The spatial pattern of forest distribution of aggregative distribution,but the degree of aggregation is not obvious,biased random,the result of the two kinds of pattern analysis were similar.