冀北山地杨桦次生林优势种群结构及时间序列预测分析

运用径级结构、静态生命表和时间序列预测分析方法,研究了冀北山地杨桦次生林群落结构和主要优势种群的动态变化过程,揭示了主要优势种群各径级数量动态规律。结果表明:冀北山地杨桦次生林群落物种组成丰富,垂直结构较为明显。山杨、五角枫和蒙古栎种群,幼龄个体多,老龄个体少,基本上属于进展型种群,而白桦种群的小径级和高径级的个体都较少,主要以幼树和中树居多,属于衰退型种群。蒙古栎种群存活曲线接近于DeeveyⅢ型。时间序列分析表明,在未来的Ⅱ径级、Ⅳ径级和Ⅵ径级中,白桦种群呈现大径级株数增加的趋势,白桦种群维持困难;山杨种群和五角枫种群小径级株数呈现减少的趋势,中径级株数呈现增加的趋势,表明山杨和五角枫保持相对稳定性,而蒙古栎呈现衰退的态势。因此对4种优势种群,分别实施不同的经营措施,促进种群的自然更新和群落演替。

Structure and time sequence prediction of dominant population in secondary poplar-birth forest in the mountainous regions of Northern Hebei

In this paper,the diversity of community structure and population structure in secondary poplar-birth forest in the mountainous regions of northern Hebei,China were studies,using diameter class,life table and time sequence analysis.The results showed that species were abundant and vertical structure was obvious in the community of secondary poplar-birth forest in the region.Populus davidiana,Acer mono and Quercus mongolica populations belonged to progressive type,with more young and less old individuals.But Betula platyphylla belonged to decline type,with more young diameter class and higher diameter class individuals.however,middle diameter class individuals were abundant.The survival curve of Quercus mongolica was approached to DeeveyⅢ type.Time sequence prediction model for Betula platyphylla populations after Ⅱ,Ⅳand Ⅵ diameter class indicated that the number of old individuals would increase,showing the maintain of Betula platyphylla populations difficult.Young diameter class individuals of Acer mono and Populus davidiana populations were found decreased,and middle diameter class individuals of Acer mono populations increased,which showed Acer mono and Populus davidiana populations were stable.However,Quercus mongolica population was declined.In order to promote population natural renew and community succession,various management measures should be taken according to the features of the four populations.