造林密度对近熟期鹅掌楸生长和材质的影响

【目的】为了培育鹅掌楸优质用材林和特用林,研究了不同造林密度对近熟期鹅掌楸用材林林分生长和材质的影响,为在亚热带山地培育不同经营目标的鹅掌楸,确定其营林措施提供科学依据。【方法】利用设置在江西分宜的鹅掌楸实验林,对3种不同造林密度的25年生鹅掌楸生长性状和木材物理力学性能等主要指标进行了测定和分析。【结果】造林密度对鹅掌楸的胸径、单株材积、径阶分布和木材气干密度的影响达到极显著水平; 对冠幅面积、树高4 m处直径、年轮宽度、木材基本密度和抗弯强度的影响达到显著水平; 对树高、通直度、第1侧枝粗度、第1侧枝角度、枝下高、蓄积量、硬度、抗弯弹性模量和顺纹抗压强度影响不显著。造林密度833株/hm²时鹅掌楸单株材积均值最大,可生产中大径材; 造林密度为1 111株/hm²时林分蓄积量最大,有较高的经济效益; 造林密度为1 666 株/hm²时,鹅掌楸木材基本密度、气干密度和抗弯强度最大,可保证木材材质。【结论】造林密度较大时,利弊兼而有之。若允许间伐,可以采用高密度造林,在第11～15年和第21～25年内进行间伐可提高大径材出材率。

Effects of planting densities on tree growth and wood quality of 25-year-old Liriodendron chinense plantations

【Objective】 The objective was to cultivate a high-quality timber forest and special forest of Liriodendron chinense, and explore the effects of different planting densities on tree growth and wood quality of L. chinense near maturity. This study can provide a scientific basis for the future of subtropical mountain afforestation and the initial planting density of Liriodendron. 【Method】 Three different levels of planting densities of a 25-year-old L. chinense was used to study the effects of initial stand density on growth, stem-form qualities, and wood basic density. 【Result】 The effects of density on the DBH, individual volume, diameter-classes, and the air-dry density were extremely remarkable. The crown area, 4 m diameter, ring width, wood basic density, and bending strength were remarkable. The height, straightness, first lateral branch roughness, first lateral branch angle, height under the branch, stock volume, wood hardness, bending modulus, and axial compressive strength are not remarkable. The best density was 833 trees/hm² for large individual volume and to obtain middle and large dimensions of wood. The planting density with the largest volume was 1 111 trees/hm², which has high economic benefits. The planting density with the largest of wood basic density and air-dry density was 1 666 trees/hm², which achieved high-quality wood. 【Conclusion】 Different planting densities, the advantages and disadvantages are both. If thinning is allowed, high density afforestation can be used, and the yield of large diameter timber can be increased by thinning in 11 to 15 years and 21 to 25 years.