绩溪光皮桦次生林的种群动态

Population Structure Dynamics of Betula luminifera Secondary Forest in Jixi County of Anhui Province,China

对绩溪光皮桦次生林种群进行了调查,以种群生命表及生存分析理论为基础,以林木径级结构代表龄级结构,编制了绩溪光皮桦种群静态生命表,分析绩溪光皮桦次生林种群结构的动态变化特点。结果表明:光皮桦种群结构呈纺锤型,幼龄个体数量偏少,中龄个体数居多,而老龄个体则相对数量较少,说明种群有衰退的趋势;在第Ⅴ龄级时该种群出现死亡高峰,其种群存活曲线属Deevey-Ⅱ型;绩溪光皮桦次生林种群具有前期种群数量少,中期稳定,末期衰退的特点。

The experiment was conducted to determine population structure dynamic and quantitative statistics of Betula luminif-era in a secondary forest of Jixi county, Anhui Province.By the population life table and survival analysis, the life table of Betula luminifera population was constructed and age classes were replaced with size-classes, therefore, the population structure dynamic of B.luminifera was explored.The results of the population structure illustrates a spindle type with a gradually decline in population.The individual plants of class I and class II are not enough.The survival curve in the pop-ulation is a Deevey-Ⅱtype with a peak of mortality in size class V.The population size ofB .luminifera declines sharply in early stage, stabilizes in middle stage and falls rapidly in last stage.