辽东山区天然更新红松幼苗种群结构与动态

本研究以辽东山区红松人工林为种源的3种不同林带(落叶松林带、针叶混交林带和阔叶混交林带)内天然更新红松幼苗为对象,运用静态生命表和生存分析方法研究天然更新红松幼苗的种群结构与动态特征。结果表明: 3种不同林带内天然更新红松幼苗的年龄结构呈“∩”型左偏态分布,前期幼苗数量较多且死亡率较高,后期不断减少,属于衰退型种群;种群存活曲线均趋于Deevey-Ⅱ型,落叶松林带内天然更新红松幼苗的期望寿命值在每个龄级内均高于针叶混交林带和阔叶混交林带;生存分析表明,3种不同林带内天然更新红松幼苗种群的生存率均随年龄增加而下降,累积死亡率则随年龄增加而逐渐上升,死亡密度函数均在Ⅱ～Ⅲ龄级后趋于平缓,危险率函数值随着年龄的增长总体呈递减趋势;时间序列预测分析表明,随着龄级的增加,种群呈增长趋势,表明该种群能够实现天然更新且有一定的增长潜力,但存在更新障碍。

Population structure and dynamics of Pinus koraiensis seedlings regenerated from seeds in a montane region of eastern Liaoning Province,China.

Based on the static life table and survival curve, we explored the population structure and dynamics of Korean pine (Pinus koraiensis) seedlings regenerated from seeds in three different forest belts of Korean pine plantation in a montane region of eastern Liaoning Province. The results showed that the age structure of Korean pine seedlings in three different forest belts (i.e., larch forest belt, mixed coniferous forest belt, and mixed broadleaved forest belt) showed a “∩” type of left skewed distribution. The abundance of seedlings was rich but the mortality rate was high in the early phase, and the abundance of seedlings decreased in the later phase, which indicated that the population was depressing. The survival curve of the population conformed to the Deevey-Ⅱ type. The life expectancy of Korean pine seedlings at each age class in larch forest belt was higher than that in mixed coniferous forest belt and mixed broadleaved forest belt. The survival analysis showed that the survival rate of Korean pine seedlings in three different forest belts decreased but the cumulative mortality rate increased with increasing age. The death density function tended to be flat after the age class of Ⅱ-Ⅲ, while the risk function value showed a decreasing trend with the increases of age. The time series predictive analysis showed that the population showed a certain growth trend with increasing age class, indicating that the population could achieve natural regeneration and have a certain growth potential, but with regeneration obstacles.