中文摘要：

【目的】探明秦岭西段油松天然次生林的种群竞争关系,为秦岭西段油松天然次生林的保护及可持续经营与管理提供科学依据。【方法】通过典型样地调查,运用Hegyi单木竞争指数模型,定量分析秦岭西段油松天然次生林油松种群种内及种间的竞争强度。【结果】油松种群的种内竞争强度（竞争指数为145.50）大于种间竞争强度（竞争指数为47.29）。在胸径处于5～25cm径级,油松种群的种内竞争强度随着径级的增加而增大,胸径≥25cm后,其竞争强度又逐渐降低。油松种群内种间竞争强度的顺序为：油松〉锐齿槲栎〉小叶杨〉白桦〉三桠乌药〉鹅耳枥〉稠李〉华山松〉山楂〉山杨〉辽东栎〉牛皮桦〉橿子栎。油松对象木的胸径大小与油松种内、种间以及整个林分的竞争强度服从幂函数关系,其胸径大小与竞争强度之间呈显著的负相关关系。由预测结果可知,当油松胸径达到25cm后,种群竞争强度明显变小,且变幅较小。【结论】油松天然次生林胸径达到25cm之前应采取必要的人工抚育,以有效减小油松种群的竞争强度,使生态系统尽快达到稳态。

英文摘要：

【Objective】 This study aimed to ascertain the competition relationship of different Pinus tablaeformis populations and provide a scientific basis for protection and sustainable management of P.tablaeformis natural secondary forests in western section of Qinling Mountains.【Method】 The intraspecific and interspecific competition intensities were quantitatively analyzed by Hegyi single-tree competition index model.【Result】 The intraspecific competition intensity（competition index 145.50） was greater than the interspecific competition intensity（competition index 47.29） in P.tablaeformis population.The competition intensity gradually increased with the increase of diameter scale when DBH was between 5 cm and 25 cm while it decreased when DBH was greater than 25 cm.The competition intensities of P.tablaeformis populations ranked as the following order：P.tablaeformisQuercus aliena var.acuteserrataPopulus simoniiBetula platyphyllaLindera obtusilobaCarpinus turczaninowiiPrunus padusPinus armandiiCrataegus pinnatifidaPopulus davidianaQuercus liaotungensisBetula albo-sinensis var.septentrionalisQuercus baronii.The competition intensities between DBH of target trees and the intraspecific,interspecific,and total stands followed exponential function.There was a significant negative correlation between competition intensities and DBH of target trees.The competition intensities of the population reduced significantly with smaller amplitude when DBH reached 25 cm.【Conclusion】 The tending management should be actualized before DBH of P.tablaeformis reaches 25 cm in natural conditions for reducing the competition intensities of P.tablaefoemis populations and stabilizing the ecosystems as soon as possible.