摘要
以5年生西南桦人工林为研究对象,设置系列高度处理开展修枝试验,调查不同修枝处理当年及3年生西南桦的生长表现,从而探讨西南桦人工幼林的最佳修枝高度。研究结果显示:各修枝处理间西南桦树高及材积增长量在修枝后3年内均无显著差异,而修枝对西南桦当年的胸径生长有显著抑制作用,且随着修枝高度的增加而胸径增长量逐渐降低,而修枝后第3年各处理间胸径增长量差异不显著。综合考虑西南桦生长规律及修枝操作上的可行性,确定5年生时树高大于9.5 m的西南桦林木,其合适的修枝高度为6 m;而树高大于8 m则适宜修枝高度为5 m;整体上其修枝强度约为30%～40%,这既不显著影响西南桦的生长,又能提高优质木材的出材率。本研究为西南桦大径级优质木材培育提供了科学依据。
A pruning trail was conducted with series of pruning heights in five-year-old plantations of Betula alnoides,so as to assess the effect of pruning heights on growth performances of Betula alnoide and determine the optimal pruning height.Diameter at breast height（DBH）,tree height and height of the lowest living branch were investigated in three years after pruning,and the volume was calculated by stem form factor at breast height.The results indicate that the increment of tree height and volume did not vary significantly under different treatments of pruning heights in three years after pruning.While DBH growth decreased apparently with increasement of pruning height and significant difference was seen between the control and other pruning treatments late in the first year after pruning,and there was no remarkable difference between them in the third year.Taking growth process and operational feasibility of pruning into consideration,the optimal pruning height was 6 meters for trees with height above 9.5 meters,and 5 meters for height above 8.0 meters,in other words,the pruning intensity was about 30%~40%.It not only had a weak effect on tree growth but also increased the production rate of high quality timber.The findings can provide scientific evidences for large-size knot-free timber production of B.alnoides.
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2012年第9期51-54,101,共5页
Journal of Central South University of Forestry & Technology
基金
"十二五"国家科技支撑课题(2012BAD21B01)
关键词
西南桦人工幼林
修枝高度
生长表现
young plantation of Betula alnoides
pruning height
growth performance
