采伐对红松种群结构与动态的影响

红松是我国长白山阔叶红松林的主要建群种,受森林采伐的影响,种群数量急剧下降,现已被列为国家二级保护植物。通过绘制种群静态生命表、生存函数、存活曲线和径级分布图,研究原始林,15%择伐、40%择伐和皆伐后恢复的天然次生林内,红松种群结构和动态的变化规律。结果表明:(1)采伐干扰对红松种群的波动周期影响不大,15%的择伐强度可以提高红松种群的生存期望。(2)原始林和15%择伐林内红松种群存活曲线均为DeeveyⅡ型,种群处于稳定期;40%择伐林内存活曲线介于DeeveyⅡ型和DeeveyⅢ型之间,种群由稳定期向成熟期过渡;皆伐林内存活曲线为DeeveyⅠ型,种群处在增长期。(3)原始阔叶红松林林、15%择伐林和40%择伐林内,红松种群径级结构均呈稳定的倒J型,且在幼树阶段均存在生长更新的停滞现象;与原始林相比,15%择伐林内幼树比例略有下降;40%择伐林和皆伐迹地,随采伐强度的增加,幼树比例明显增大。(4)方差分析表明,4个种群的生存过程差异较大,采伐干扰对红松种群生存过程的影响达到显著水平。

Impact of tree harvesting on the population structure and dynamics of Pinus koraiensis (Pinaceae)

Pinus koraiensis is the main species present in Korean pine and broad-leaved mixed forests typically found on Changbai Mountain. Tree logging has had a significant impact on this species, resulting in its decline; it is currently listed as a State Protection Species (category ii). Here, we have presented the static life table, survival function table, survival curve, and diameter class distribution for P. koraiensis and analyzed its population structure and dynamics in a primary forest and secondary forests subjected to 15% selective logging, 40% selective logging, and clear cutting. The results showed that (1) harvesting did not significantly influence fluctuations in P. koraiensis populations. In addition, 15% selective logging improved the survival prospects of the populations. (2) In the primary forest and the forest subjected to 15% selective logging, population survival followed a Deevey II curve and was stable. In the forest subjected to 40% selective logging, population survival followed a pattern intermediate between the Deevey II and Deevey III curves, and the population was in a transition zone between a stable period and a mature period. In the forest subjected to clear cutting, population survival followed a Deevey I curve, and the trees were in the growth period. (3) Diameter class distribution for all P. koraiensis populations followed a stable inverted J curve. In all cases, the results showed evidence of growth retardation during the sapling stage. The proportion of young trees was slightly lower in the forest subjected to 15% selective logging than in the primary forest; however, it increased concomitantly with the increase in cutting intensity in the forests subjected to 40% selective logging and clear cutting. (4) Analysis of variance showed that population survival varied significantly among the forests studied and was significantly influenced by tree logging.