桉树相思树混交林对薇甘菊入侵的控制效果评价

Evaluation of the Control Effect of Eucalyptus spp.and Acacia confusa Mixed Forest on the Invasion of Mikania micrantha

[目的]探索桉树混交林对薇甘菊的入侵控制效果。[方法]以桉树纯林作对比,设置1行桉树+1行相思树(混交模式A)、2列桉树+2列相思树(混交模式B)2种混交模式,对3种造林模式的林木生长状况、薇甘菊生物量、叶生物量、林分透光度、薇甘菊盖度等相关指标进行分析,揭示控制薇甘菊的关键因素。[结果]混交林中,相思树的平均树高、平均胸径、平均冠幅、单株叶生物量等均比桉树纯林的大;林分透光度、林分薇甘菊生物量表现为桉树纯林>混交模式B~混交模式A(P<0.05),林分乔木层的总叶生物量、薇甘菊生物量表现为混交模式A~混交模式B>桉树纯林;3种造林模式内,薇甘菊盖度达70%以上只在桉树纯林内存在,盖度只有5%~10%或者没有薇甘菊的只在混交林内存在。[结论]综合以上因素,3种造林模式对薇甘菊入侵控制效果为混交模式A~混交模式B>桉树纯林,说明林分密度、枝叶繁茂程度、林分透光度等因素是控制薇甘菊入侵的关键。

[Objective]To explore the invasion control effect of Eucalyptus spp.mixed forest on Mikania micrantha.[Method]This study compared pure Eucalyptus spp.forest with two mixed models:1 row of Eucalyptus spp.+1 row of Acacia confusa(mixed mode A)and 2 rows of Eucalyptus spp.+2 rows of Acacia confusa(mixed mode B).The growth status,Mikania biomass,leaf biomass,stand transparency and Mikania micrantha coverage of the three afforestation models were analyzed and the key factors controlling Mikania micrantha were revealed.[Result]The results showed that in the mixed forest,the average height,average diameter at breast height,average crown width,and single leaf biomass of Acacia confusa were higher than those of pure Eucalyptus spp.forests;The order of stand transmittance and biomass of Mikania micrantha is as follows:pure Eucalyptus spp.forest>mixed mode B-mixed mode A(P<0.05).The order of total leaf biomass and Mikania micrantha biomass in the tree layer of the forest is as follows:mixed mode A-mixed mode B>pure eucalyptus forest;among the three afforestation modes,the coverage of Mikania micrantha reaches over 70%and only exists in the pure eucalyptus forest,with a coverage of only 5%-10%or only in the mixed forest without Mikania micrantha.Based on the above factors,the effectiveness of the three afforestation modes in controlling the invasion of Mikania micrantha is as follows:mixed mode A-mixed mode B>Eucalyptus spp.pure forest,indicating that factors such as forest density,degree of branch and leaf flourishing,and forest transparency are the key to controlling the invasion of Mikania micrantha.[Conclusion]The research results provide a reference basis for constructing Eucalyptus acacia mixed forests in the southeastern region of Guangxi to control the occurrence of Mikania micrantha.