摘要
桉树大径材培育是实现当前桉树产业可持续发展的有效途径。林分密度直接影响林木胸径生长,间伐是调整林分密度最为常用的手段。本试验以6 a生不同种植密度桉树优良无性系试验林为研究对象,探讨了进行不同强度的一次性间伐后,12 a生林分生长、径级分布、大径材生长及木材收益的变化。研究结果表明:不同种植密度与间伐强度试验林,林分胸径、树高、枝下高、冠幅、单株材积及林分蓄积量差异显著。其中,以1 100株·hm^(-2)种植密度+30%~50%间伐强度处理,林分胸径、树高、枝下高、冠幅、单株材积生长量最大,以1 100~1 650株·hm^(-2)种植密度未间伐时林分蓄积量最大;径级分布受种植密度与间伐强度影响显著,大径级(≥28 cm)林木数量占比以低种植密度(1 100株·hm^(-2))+30%~50%强度间伐时较大,为82%~92%;间伐后林分保留株数与大径材蓄积量无关(R^(2)=0.31),与林分中大径材蓄积量占比、大径材单株出材量、大径材出材率呈明显的负相关线性关系(R^(2)=0.77~0.85);不同种植密度与间伐强度处理下林分木材销售收益与木材利润差异显著,其中木材利润与林分总出材量无明显相关性(R^(2)=0.30),与大径材出材量呈显著的正相关线性关系(R^(2)=0.92),整体上试验9个处理中以1 100株·hm^(-2)种植密度未间伐所获木材收益最大,其次是1 100株·hm^(-2)种植密度+30%间伐强度与1 650株·hm^(-2)种植密度+未间伐处理。桉树大径材培育可选择1 100株·hm^(-2)种植密度无需间伐即可获得较好经营效果,生产中可采用长短周期相结合模式,即1 100株·hm^(-2)种植密度+30%间伐强度。
Eucalyptus large-diameter timber cultivation is an effective way to achieve sustainable development of Eucalyptus industry.Stand density directly affects the DBH growth of trees,and thinning is the most commonly used means to adjust stand density.In this study,6-year-old Eucalyptus clone plantations with different planting densities were used to investigate the changes of growth,diameter class distribution,large diameter wood growth and wood income of 12-year-old stand after one thinning with different intensities.The results showed that stand DBH,tree height,under-branch height,crown width,individual volume and stand volume were significantly different under different planting density and thinning intensity.The treatment of 1100 plants/hm^(2) planting density+30%~50%thinning intensity generated best effect with the DBH,tree height,branch height,crown width and individual volume growth of the stand the largest,while the stand volume was the largest when the planting density was 1100~1650 plants/hm^(2).The distribution of diameter class was significantly affected by planting density and thinning intensity.The proportion of trees with large diameter class(≥28 cm)was 82%~92%under low planting density(1100 plants/hm^(2))+30%~50%thinning.After thinning,there was no correlation between the number of retained trees and the volume of large-diameter timber(R^(2)=0.31),but there was a significant negative correlation between the number of retained trees and the proportion of large-diameter timber volume,the output of single large diameter timber and the output rate of large diameter timber(R^(2)=0.77~0.85).There were significant differences in timber sales revenue and timber profits under different planting densities and thinning intensities.There was no significant correlation between timber profits and total timber output(R^(2)=0.30),while there was a significant positive correlation between timber profits and large-diameter timber output(R^(2)=0.92).On the whole,among the 9 treatments applied,the timber revenue obtained without thinning at 1100 plants/hm^(2) planting density was the largest,followed by 1100 plants/hm^(2) planting density+30%thinning and 1650 plants/hm^(2) planting density without thinning.The results showed that 1100 plants/hm^(2) planting density could be chosen for Eucalyptus large-diameter timber cultivation without thinning to obtain ideal management results.If considering the promotion of application in production,the long-term and short-term combination mode could be adopted,that is,1100 plants/hm^(2) planting density+30%thinning intensity could also obtain relatively high wood yield.
作者
刘再兴
冯桂乾
王涛
LIU Zai-xing;FENG Gui-qian;WANG Tao(Yunfu Forest Farm of Guangdong Province,Yunfu,Guangdong 527300;Yunan Forest Farm,Yunfu,Guangdong 527300;Institute of Tropical Forestry,Chinese Academy of Forestry Guangzhou,Guangzhou,Guangdong 510000)
出处
《陕西林业科技》
2023年第1期112-117,141,共7页
Shaanxi Forest Science and Technology
关键词
桉树
大径材
间伐强度
密度
木材收益
径级分布
Eucalyptus robusta
large diameter timber
thinning
density regulation
wood revenue
