造林密度对黄梁木幼林生长和林分蓄积的影响

【目的】通过分析造林密度对3年生黄梁木Anthocephalus chinensis幼林的树高、冠幅、枝下高、胸径、单株材积和林分蓄积等的影响,探究造林密度与黄梁木人工幼林生长的关系。【方法】采用完全随机区组设计,共设5个造林密度,分别为625、667、833、1 667和2 500株·hm~(-2)。采用每木检尺法,测量每个小区内9株试验树主要生长指标。采用单因素方差分析和Duncan’s多重极差检验法比较不同造林密度间的差异,采用相关性分析对不同数据组间的相关性进行分析。【结果】造林密度对黄梁木的树高、冠幅、枝下高和林分蓄积生长有极显著影响(P0.01)。树高(y)与密度(x)呈极显著正相关关系,回归方程为y=-4.000 0×10~(-7)x~2+0.001 6x+8.270 3;林分蓄积(y)与密度(x)呈极显著正相关关系,回归方程为y=-1.000 0×10~(-5)x~2+0.112 7x-12.664 0;冠幅(y)与密度(x)呈极显著负相关关系,回归方程为y=15.942 5~(-4.000 0×10~(-5)x)。研究还发现,胸径(y)与冠幅(x)存在极显著正相关关系,回归方程为y=9.661 3x~2-103.950 0x+293.870 0。【结论】就黄梁木幼林而言,造林密度为2 500株·hm~(-2)幼林的树高和林分蓄积最大。

Effects of planting density on the growth and stand volume of young Anthocephalus chinensis plantation

Objective] To explore the effects of planting density on the growth of Anthocephalus chinensis plantation, namely, on tree height, canopy width, height under branch, diameter at breast height (DBH), individual tree volume and stand volume. Method]Planting densities of 625,667,833,1 667 and 2 500 trees·hm-2 were established in a complete randomized block design. Based on the method of tally, the major growth indicators of nine experimental trees in each block were measured. Differences among different planting densities were analyzed using one-way ANOVA and Duncan ’ s Multiple Range Test. Relationship among different traits and planting density were explored using correlation analysis.Result]Planting density had significant effects on tree height, canopy width, height under branch, and stand volume (P<0. 01). Tree height(y) and planting density(x) were significantly positively correla-ted, and the regression equation was y = -4. 000 0 × 10 -7x2 + 0. 001 6x + 8. 270 3. Stand volume(y) and planting density( x) were significantly positively correlated, and the regression equation was y =-1. 000 0 ×10 -5x2 + 0. 112 7x-12. 664 0. Canopy width(y) and planting density(x) were signifi-cantly negatively correlated, and the regression equation was y =15. 942 5 -4. 000 0 × 10-5x . Canopy width (y) and DBH(x) were significantly positively correlated, and the regression equation was y =9. 661 3x2 -103. 950 0x + 293. 870 0. Conclusion]For young A. chinensis plantation, the planting density of 2 500 trees·hm-2 leads to the optimum results with the highest stand volume and tree height.