摘要
以陕西省黄龙山林区油松人工中龄林为研究对象,分析了不同间伐保留密度(3 900、3 000、2 250株·hm-2和1 800株·hm-2)的4类林分油松林木的生长特征及树干形质的差异。结果表明:间伐保留密度对油松林木生长的影响不同,随着保留密度的减小,林木胸径增大,且保留密度为1 800株·hm-2时,可以显著促进胸径的增大。林木单株材积随着保留密度的减小而明显增大,林分蓄积不断减小并趋于稳定;保留密度对树高的影响较弱;保留密度对林木树干形质的影响也不同,随着间伐保留密度的减小,林木尖削度、径高比、通直度、分枝数及分枝基径均增大,分叉率先降低后上升,活枝下高随保留密度的减小而降低。方差分析表明,除树高和林分蓄积外,间伐保留密度对油松中龄林林木生长及树干形质均有显著性影响。
To investigate the effects of the reserve density on tree growth and stem form quality after intermediate cuttings, differences in tree growth characteristics and stem form quality were analyzed for middle-aged Pinus tabulaeformis plantation from four reserve densities （3 900, 3 000, 2 250 trees·hm^-2 and 1 800 trees·hm^-2）. The results indicated that reserve density had various degrees of impact on growth characteristics. As reserve density decreased, the DBH of trees increased obviously and there was a substantial increase when the reserve density was 1 800 trees·hm^-2. The average volume of individual tree increased obviously as reserve density decreased. Meanwhile, stand volume reduced evidently and tended towards stability with the reserve density reduced. Reserve density had no significant effect on tree height. The results also showed that reserve density had various degrees of impact on stem form quality. As reserve density decreased, trees stem taper, the ratio of diameter to height, stem straightness, number of branches and average base diameter of branches all increased. Forking ratio decreased at first and then rose again. Height under living branch lowered significantly with the decrease of reserve density. Variance analysis showed that reserve density had a significant influence on both growth characteristics and stem form quality.
出处
《西北林学院学报》
CSCD
北大核心
2015年第1期172-177,共6页
Journal of Northwest Forestry University
基金
"十二五"国家科技支撑计划项目(2012BAD22B0302)
关键词
油松中龄林
保留密度
林木生长
树干形质
方差分析
middle-aged Pinus tabulaeformis plantation
reserve density
growth characteristics
stem form quality
variance analysis
