湿地松人工林不同密度效应分析

Effect Analysis on the Different Planting Densities of Pinus elliottii

以19、21年生不同种植密度的湿地松(Pinus elliottii)人工林为研究对象,分析林分密度和采脂对生长的影响。结果表明,随着林分密度的增大,林分胸径、保存率出现下降趋势,而材积、林分内小径级的株数不断增加,小径材出材量比例增大。随着树龄的增加,各密度林分保存率下降,而其它林分生长指标均上升;19年生时密度与树高差异不显著,但21年生时不同密度的林分树高差异显著。采脂试验表明,密度越大,单株产脂量越小,但单位面积产脂总量越高,1 080株/hm2和1 680株/hm22种密度采脂前后的树高、胸径和材积差异显著。相关性分析表明,材积与胸径的相关性最高,而与树高的相关性较低。综合分析表明,2 520株/hm2可培育较多的中小径材,1 080株/hm2和1 320株/hm22种密度适用于培育湿地松大、中径材。

The influence of planting density and resin tapping on forest growth was analyzed by using 19and 21-year-old Pinus elliottii with different planting densities as materials. The results indicated that DBH and preservation rate declined with the increasing of planting density,while the volume of wood and number of small stands increased with the increasing proportion of volume. The reservation rate with different planting densities declined and the other growth indices rose with the increasing of tree age. The height had no significant difference with different densities at 19-year-old,while at 21-year-old,the difference was obvious. Tapping tests showed resin yield of single tree was lower with the higher planting density,but the resin yield of unit area increased. The differences of height,DBH and volume were obvious with the densities of 1 080 strain /hm2and 1 680 strain /hm2by resin tapping. By correlation analysis,volume and DBH had high correlation,while hight had low. More middle and small stands were cultivated with 2 520 strain /hm2. It was suitable for cultivating large and middle stand with 1 080 strain /hm2and 1 320 strain /hm2.