宝天曼国家级自然保护区栎类天然林林分空间结构特征

利用混交度、大小比数和角尺度3个空间结构参数,结合最近相邻木平均距离研究了宝天曼国家级总体上处于弱度混交水平;3个龄级林分平均角尺度均在0.475～0.517范围内,其分布频率集中在0.5的尺度上,分别占各自结构单元总数的51%、55%、45%;锐齿栎平均大小比数在3各龄级上分别为0.331、0.469、0.549,总体处于绝对优势地位;随着龄级增加,参照树与4株最近相邻木的平均距离呈现递增的趋势,但均集中在3 m以内。

Spatial Structure Characteristic of Quercus Natural Forests in Baotianman National Nature Reserve

Three spatial structure parameters(mingling degree,neighborhood comparison and uniform angle index) and average distances of neighborhood trees were used to analyze the spatial structure characteristics of Quercus aliena var.acuteserrata natural forests of different age classes in Baotianman National Nature Reserve in Neixiang County,Henan Province.Results showed that these three age classes of forests could be classified intoⅠ class(4.5cm≤d<9.5cm),Ⅱ class(9.5cm≤d<14.5cm)and Ⅲ class(d≥14.5cm)by diameter at breast height(d),and the average mingling degrees were 0.414,0.413 and 0.490,respectively.There was no obvious difference in the average mingling degree,indicating a less-mixed degree.The uniform angle indexes ranged from 0.475 to 0.517,and its frequencies were 51%,55% and 45%,respectively,and concentrated at 0.50.The neighborhood comparison values were 0.331,0.469 and 0.549,respectively,suggesting an absolute dominance.The average distance between reference tree and four neighboring trees increased gradually with increasing age class,but concentrated within the distance of 3m.