目标树经营对云冷杉针阔混交林单木生长的影响研究

Study on Effectiveness of Crop Tree Management for Individual Tree Growth in Spruce-Fir Coniferous-Broadleaved Mixed Forest

[目的]探讨目标树经营对针阔混交林单木生长的影响,为针阔混交林群落生态恢复演替和森林质量精准提升提供技术支撑。[方法]以吉林省汪清林业局的云冷杉针阔混交林为研究对象,区分不同径级和不同树种,使用方差分析判断目标树经营与对照间、不同自由生长空间(FTG)之间目标树的胸径、材积生长量差异。[结果]1)与对照相比,除径级Ⅲ的材积生长量差异不显著外,目标树经营下的各径级目标树的胸径和材积生长量均差异显著,随着径级的增大,目标树的生长提升效果下降明显;2)目标树经营对先锋树种目标树生长的提升或抑制作用不显著,但能显著促进顶级树种和伴生树种目标树生长,且顶级树种更优;3)随着自由生长空间的增加,不同径级目标树的生长量均增大,但径级Ⅲ的材积生长量差异同样不显著;各径级胸径生长量在自由生长空间为4时(FTG4)最大,材积生长量在自由生长空间为3时(FTG3)最大;与经营前相比,最少需要多释放出2个方向的自由生长空间才会显著促进目标树生长;4)紫椴适合疏开2~3个生长方向,臭冷杉适合疏开2~4个生长方向,红松和鱼鳞云杉适合疏开3~4个生长方向。[结论]目标树经营可以显著促进目标树的生长,且有利于群落的恢复演替;云冷杉针阔混交林的目标树经营应重点关注中小径级,其次是大径级;目标树应按照不同树种的适宜性,释放2~4个方向的自由生长空间。

[Objective]The aim of this study is to explore the effect of crop tree management on the growth of individual trees in coniferous-broadleaved mixed forest,and provide technical support for the ecological restoration and succession of coniferous-broadleaved mixed forest community and forest quality precision improvement.[Method]The spruce-fir coniferous-broadleaved mixed forest in Wangqing Forestry Bureau of Jilin Province was selected as the research object.Variance analysis was applied to analyze the influence on DBH increment and volume increment caused by crop tree management and the control group,as well as by the different number of free-to-growth(FTG),according to different diameter classes and tree species.[Result](1)Compared with the control,the increment of DBH and volume of crop trees of different diameter classes under crop tree management were significantly different,except for the crop trees of diameter classⅢ.With the increase of diameter class,the growth promotion effect of crop trees decreased significantly.(2)Crop tree management did not significantly improve or inhibit the growth of crop trees of pioneer tree species.However,it could significantly promote the growth of crop trees of climax and associated tree species,especially for the climax tree species.(3)With the increase of free-to-growth space,the growth of crop trees of different diameter classes increased,but the difference of volume increment of diameter classⅢwas not significant.The growth of DBH reached the maximum in FTG4 and the growth of volume reached the maximum in FTG3.Compared with before management,at least two directions of free-to-growth space needed to be released to significantly promote the growth of the crop tree.(4)Tilia amurensis was suitable for 2-3 growth directions,Abies nephrolepis was suitable for 2-4 growth directions,Pinus koraiensis and Picea schrenkiana were suitable for 3-4 growth directions.[Conclusion]Crop tree management can significantly promote the growth of crop tree,and is conducive to community restoration and succession.The crop tree management of spruce-fir coniferous-broadleaved mixed forest should focus on small and medium-sized trees,followed by the large-sized trees.2-4 directions of free-to-growth space should be released according to the suitability of different tree species.