昆明西山云南油杉针阔混交林的群落结构及其更新特征研究
A study on the structure and regeneration ofKeteleeria evelyniana mixed forest in Xishan,Kunming
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摘要: 为揭示现存云南油杉混交林的稳定性和演替趋向,采用标准样地设置法研究了昆明西山云南油杉(Keteleeria evelyniana)针阔混交林的群落结构及其更新特征.结果表明:混交林的群落垂直结构较为复杂,乔木上层主要是云南油杉,个体数量不多;滇青冈(Cyclobalanopsis glaucoides)和高山栲(Castanopsis delavayi)分布在群落乔木中层以下;在乔木中、下层中云南油杉植株较多,但大多为枯立、断梢或生长不良的植株.云南油杉的幼苗和幼树在林下层更新不足,云南油杉种群正处于衰退时期.然而,滇青冈和高山栲个体径级分布为连续分布,且通过实生繁殖和萌生繁殖2种方式进行更新,主要以萌生苗方式更新,使其具有很大的幼苗库,为其更新提供强大的物质基础.因此,随着时间的推移,云南油杉种群极有可能被滇青冈或高山栲种群所取代,混交林将会演化为以滇青冈或高山栲为建群种的半湿润常绿阔叶林. Abstract: In order to reveal the stability and succession trend of Keteleeria evelyniana mixed forest,the community structure characteristics and regeneration of Keteleeria evelyniana mixed forest were studied by using sample plot method in Xishan,Kunming.The results indicated that there was a complicated vertical structure in the mixed forest.Keteleeria evelyniana was the most dominant specie in the upper tree layer with fewer individuals,and the middle tree layer was dominated by Cyclobalanopsis glaucoides and Castanopsis delavayi.In the lower tree layer,there were more individuals of Keteleeria evelyniana,which included many standing death,branch breakage or poor growth individuals.The population of Keteleeria evelyniana was trending to decline for the shortage of seedlings and saplings in the understorey.While,the DBH structure of the populations of Cyclobalanopsis glaucoides or Castanopsis delavayi showed continuous distribution,and they could regenerate through seedling bank and sprouting under the closed forest canopy,of which asexual reproduction was preponderant.The study implies that the population of Keteleeriaevelyniana is being replaced by Cyclobalanopsi sglaucoides and Castanopsis delavayi,and then mixed forest will be changing into evergreen broad-leaved forest which will be dominated by Cyclobalanopsisglaucoides and Castanopsisdelavayi gradually.
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