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通过对马尾松4种造林密度的定位观测分析结果表明，不同造林密度对胸径、单株村积生长的影响达到显著性差异，对树高生长影响差异不显著，不同密度林分径级分布差异明显，密度为2500株／hm2和1250株／hm2的林分，其胸径≤6cm径阶的株数占57．2％和45．9％，≥8cm径阶的株数占42．8％和54．1％；而密度为10000株／hm2和5000株／hm2的林分，其胸径≤6cm径阶的株数占89．6％和76％，≥8cm径阶的株数占10．4％和24％；不同径级林分的合理密度通过胸径与树冠面积的相关关系，用回归直线方程y=a＋bx分别求得各胸径最低保留株数，作为间伐强度、间伐开始期和间伐重复期的参考依据。
Through the observation and analysis of the 4 afforestation density of Pinus massoniana, the results showed that the effect of different afforestation density on the DBH and single village plot growth had significant difference, but no significant difference on tree height growth. Obviously, the plantations with density of 2500 plants / hm2 and 1250 plants / hm2 accounted for 57.2% and 45.9% of the diameter at diameter ≤6cm and 42.8% and 54% of the diameter at ≥8cm. 1%. For stand with density of 10000 plants / hm2 and 5000 plants / hm2, the number of DBH with diameter of 6cm or less was 89.6% and 76%, the number of DBH with diameter ≥ 8cm was 10.4% and 24% . The reasonable density of different diameter forest stands was calculated by using regression equation y = a + bx according to the relationship between DBH and crown area. The minimum DBH numbers were used as reference for thinning intensity, beginning of thinning and thinning repetition period.