【作者】 杨安学；

【导师】 丁贵杰； 孙建昌；

【作者基本信息】 贵州大学 ， 农业推广， 2008， 硕士

【摘要】 林分密度调控,是培养杉木大径材的主要技术措施,本研究旨在通过不同造林密度、间伐后保留不同密度林分的对比试验,确定培养杉木大径材的合理密度、在不同的林龄阶段的林分密度调控技术,保证林木的个体和群体得到最大的生长量。本研究以人工杉木林为试验对象,进行不同造林密度和中龄林间伐两个不同阶段的研究,分析各试验林分密度对胸径、单株材积、林分蓄积和冠幅的影响。对不同造林密度的林分进行15年的连续调查和分析,结果表明：造林密度对树高有一定影响,但差异不显著；胸径、单株材积和冠幅随密度的增大而减小,4年后各区组间差异一直显著,并且差异越来越大；蓄积量随密度的增加而增加,在7-12年差异显著。随着密度的增加,小径阶株数百分比明显增大,大径阶株数急剧减小,株数分布曲线峰值(中央径阶)偏左,每降低一个密度级,峰值向右移动一个径阶。间伐后,林分密度对林分平均胸径的影响显著,胸径随年龄的增加而递增；从方差分析的F检验值的变化看出,F值随林龄的增加而减小,差异均不显著；林分平均树高生长随年龄增加而递增,通过方差分析,差异不显著；林分密度对林分平均单株材积有显著影响,而且影响的规律和林分密度对林分平均胸径的影响相同,单株材积密度Ⅰ-1125株/hm2更加明显的大于另外三个密度处理下的林分样地,并且密度间差值随年龄增加而增加；相同密度下林分蓄积随林龄增加而增加,密度Ⅰ-1125株/hm2与密度Ⅳ-1575株/hm2的蓄积量明显大于密度Ⅲ、Ⅳ下处理的林分,方差分析的结果：F检验值随林龄增加而减小,不同密度对林分的蓄积量均无差异。更多还原

【Abstract】 The density regulation is the main technique means of cultivating large diameter timber for Cunninghamia lanceolata, through the different density and different forest ages trials, the rational density and regulation technique for different forest ages would be determined to get maximum growth of the Cunninghamia lanceolata(Lamo)This research with Cunninghamia lanceolata plantation for example, carry on a different planting density, different density regulation and selecting feeling at middle-aged forest,to analysis the effects of each trials on the DBH, tree volume, forest volume and crown.Through different planting density investigated and analysis for 15 years, the results showed that the planting density had certain influence on the tree height, but non significant difference. The DBH tree volume and crown reduced with the density increased, with a significant difference after 4 years, and the difference increased with the ages; stand volume increased with the increment of the density, and difference at 7-12 years.Along with the increment of the density, small diameter hold a large proportion and big diameter had the few percentages, The tree number distribute curve value to be partial to left, each lower a density class, peak value rightwards move a diameter rank.After felling, the influence of the density upon the average diameter was significant, DBH increased with age incresing;From square variation analysis of F test value can see, F value reduced with ages increment but non significant difference; the average tree height increased with the age increment but non significant difference.The density had a significant effect on the tree volume and the effect was same as DBH, The density of 1125 stub/hm2 had more obvious than other treatments and the density difference was increased with the age increasing, under the same density, the stand volume increased with the age increasing. From a variation test, F value reduced with the age increasing and the effect of density on the stand volume had non significant difference.更多还原