云南松天然林的种内和种间竞争

目的]通过对云南松天然林内云南松种内和种间竞争强度的测定,分析揭示竞争强度在云南松群落内的动态变化规律及云南松种群的生态适应机制.方法]在云龙天池自然保护区云南松天然林设置样方进行群落学调查的基础上,采用Hegyi单木竞争指数模型,以云南松为对象木,定量分析林分、对象木、竞争木的竞争强度,采用回归分析方法建立对象木胸径与林分、种内、种间竞争强度的函数模型.结果]天池自然保护区云南松天然林的种内和种间竞争强度分别为80.16%和19.84%;云南松种内与主要伴生树种种间竞争强度大小顺序为:云南松种内> 水红木> 华山松> 米饭花> 大白花杜鹃> 槲栎> 马缨花> 旱冬瓜;云南松与整个林分、伴生树种以及种内的竞争强度与对象木胸径之间存在显著负相关关系,对象木胸径越大,其竞争能力越强.结论]云南松天然林内云南松的竞争压力主要来自种内竞争;林分种内及种间竞争强度与对象木胸径间存在CI=AD^-B形式的幂函数关系;胸径20 cm以上云南松的竞争压力变化趋于平缓,胸径20 cm以下的云南松中、幼林是抚育管理的重点林分.

Intraspecific and Interspecific Competition of Pinus yunnanensis Natural Forest

Objective]By investigating the intraspecific and interspecific competition of Pinus yunnanensis natural forest in Tianchi Natural Reserve of Yunlong County, Yunnan Province to reveal the rule of dynamic changes of intensity of competition within the community and the ecological adaptation mechanism of P. yunnanensis.Method]Based on survey of substantial community plots, the competition intensity of forest stand, objective trees, competitive trees were analyzed by using Hegyi individual competitive indices (CI) model. The function model between DBH and the whole competition, intraspecific competition, interspecific competition were established by regression analysis method. Result]The intraspecific and interspecific competition intensity of P. yunnanensis accounted for 80.16% and 19.84% in the total competition intensity, respectively, indicating that the competitive trees of P. yunnanensis natural forest were mainly come from intraspecific competition. The order of the intraspecific and interspecific competition intensity of the main accompanying species at the community level was: intraspecific > Viburnum cylindricum > P. armandii > Lyonia ovalifolia > Rhododendron decorum > Quercus aliena > Rhododendron delavayi > Alnus nepalensis. Conclusion]There was a significantly negative correlation between the competition index of P. yunnanensis with the whole forest, accompanying species, intraspecific and the DBH of the objective trees, and nearly conformed to power function (CI=AD^-B). The larger the DBH of the objective trees, the smaller the competitive trees in P. yunnanensis natural forest. The results predicted by the model is that when the DBH of P. yunnanensis is larger than 20 cm, the competitions will be less in intensity. The medium and young forests of P. yunnanensis with DBH below 20 cm should be the focus of tending and management.