摘要
该文对科尔沁沙地雨养条件下杨树(白城41号)固沙林的密度、配置与林木胸径、株高、冠幅、单株材积以及林分单位面积木材蓄积量随林龄增大的动态关系进行了试验研究.结果表明:1～5年生林木的生长不受密度的影响,密度大,单位面积木材蓄积量大.6龄以后,密度对林木生长的影响开始表现出来,并随着林龄的增大,密度小的林分较密度大的林分的林木胸径、单株材积量逐年显著增加.大约在11年生之前,林分单位面积木材蓄积量受密度的影响而相互变化,其后趋于稳定,以密度为825株hm2的林分的最大,可达153.39m3hm2,其他依次为540>420>1215株hm2(35.18m3hm2).密度在400～1000株hm2的杨树人工林干、枝、叶量比例合理.同密度时,充分发挥林木边行优势的行带式配置结构的林分比均匀分布的林分的胸径、单株材积生长快,单位面积木材蓄积量显著增加.造成行列带林分生长优势的一个重要原因是明显地出现了一个土壤水分主要利用带及其外侧的高含水率的土壤水分渗漏补给带,确保水分的持续利用.
The relationships between high-yield forest densities, planting composition and the average D. B. H, height, canopy width, tree volume and forest volumes as well as changes with growth of stand of No. 41 Baicheng poplar at the natural rainfall condition were studied in Keerqin sandy land of dry sub-humid. The results show that planting density has no effect on the growth at age of 1-5 years. The forest volumes per hectare increase with the density. After 6 years of planting, the effects of density on tree growth show gradually. The D. B. H. and tree volume increase faster for the low-density stands than that for the highdensity stands, with the increase of the stand＇s age. After 11 years, this effect towards stable. The forest volume （153.39 m^3/hm^2 ） is greatest at a density of 825 trees/hm^2 , and that at 540 trees/hm^2 is greater than at 420 trees/hm^2, and the volume （35.18 m^3/hm^2） is least at 1 215 trees/hm^2. The proportion of sterns, branches and foliages are optimum at 400-1 000 trees/hm^2. The trees in rows in the forest edge become dominant. The D. B. H., volume and volume increment of dominant trees grow faster than those of uniform crop＇s in the forest at the same density. The roots of dominant trees absorbed more water because higher stand growth rate of forest belt mainly resulted from a major water use zone and a la-leral zone supplied by outer soil areas with higher moisture content.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2005年第4期33-38,共6页
Journal of Beijing Forestry University
基金
"973"国家重点基础研究发展规划项目(G2000048705)
国家自然科学基金项目(30360089)
国家林业局项目"沙地雨养植物区试".
关键词
杨树
密度
配置
生长过程
poplar, density, composition, growth process
