3种热带相思树种木材物理力学及纤维特征研究

A Study on the Physical and Mechanical Properties and Fiber Features for Three Tropical Acacia Tree Species

相思树种在我国热带及南亚热带地区生长迅速,适应性强,人工林种植发展甚为迅速。了解相思树种的木材物理力学及纤维性能,可为相思树种的定向培育及其木材高质量加工利用提供理论指导。本研究分别以5年和8年生马占相思Acacia mangium、大叶相思A.auriculiformis、厚荚相思A.crassicarpa木材为对象,按照国家标准对其物理力学指标(密度、干缩特性、硬度、顺纹抗压强度和抗弯强度)和纤维性状(木纤维长度、宽度、腔径和双壁厚)进行系统测试和分析。结果表明:3种相思的木材基本密度达0.37~0.56 g/cm^(3),体积干缩率仅7.83%~8.91%,木材硬度、顺纹压力、抗弯强度分别为3.90~6.85 KN、41.82~52.56 MPa、83.53~l07.30 MPa,其木材变形性远小于尾叶桉Eucalyptus urophyllus、巨桉E.grandis等树种;纤维长度在1066.71~1326.90μm,是优良的阔叶材造纸原料。厚荚相思和大叶相思的木材基本密度和木材物理力学性明显高于马占相思。纤维形态上厚荚相思较细长,马占相思较宽大,大叶相思相对较短。综合不同年份的隶属函数分析,厚荚相思综合性能最佳。

Due to rapid growth and strong adaptability,the development of artificial forest planting for A-cacia tree species is very rapid.Understanding the wood physical mechanics and fiber properties of Acacia spe-cies provides theoretical guidance for the targeted cultivation and high-quality wood processing and utilization of Acacia species.The wood samples of Acacia mangium,A.auriculiformis and A.crassicarpa were collected from the plantations at the ages of 5 years and 8 years to analyze the physical and fiber properties such as density,dry shrinkage characteristics,hardness,compressive strength parallel to grain,bending strength,length,width,cavity diameter,and double wall thickness of wood fibers were systematically determined and analyzed accord-ing to the Chinese national standards.The basic density of the wood of these three types of Acacia species reached 0.37-0.56 g/cm^(3),and the volume dry shrinkage rate was only 7.83%-8.91%.The hardness,grain pressure,and bending strength of the wood were 3.90-6.85 KN,41.82-52.56 MPa,and 83.53-107.30 MPa,respectively.Their wood deformability was much lower than that of tree species such as Eucalyp-tus urophyllus and Eucalyptus grandis;Fiber length was between 1066.71 and 1326.90μm.It is an excellent raw material for hardwood papermaking.The wood basic density and physical and mechanical properties of A.auriculiformis and A.crassicarpa were significantly higher than those of A.mangium.In terms of fiber mor-phology,the A.crassicarpa was relatively slender,the A.mangium was relatively broad,and the A.auriculiformis was relatively short.Based on the analysis of membership functions from different years,the comprehensive performance of A.crassicarpa was the best.The research results provided a reference for the di-rectional cultivation of Acacia species and its wood processing.