ABSTRACT

Aim of this study is to evaluate the potential of a rational utilization of wood and bark of the invasive species of tree-of-heaven (Ailanthus altissima (Mill.) Swingle), through their thorough chemical characterization. Extractives, celluloses, hemicelluloses, lignin, and ash contents of wood and bark material of different tree sections were examined, using wet chemical analyses/extractions. The horizontal variability of the chemical composition of the stems from pith to cambium was investigated, as well as the differences between early- and late-wood, different annual rings, sapwood and heartwood, and differences between wood and bark. The material’s equilibrium moisture content, density, pH, colour, and calorific value were also determined. Bark material presented higher extractives, slightly higher lignin, much higher ash, and slightly lower holocellulose content than wood. As the tree-age increases, the wood and bark present lower lignin, but a linear increase of holocellulose and extractives. The heartwood demonstrated more extractives, lignin and ash, and less holocellulose than sapwood. Very low ash contents and high calorific values constitute features highly crucial for its utilization in solid biofuel production. The optimum harvesting time for the highest possible utilization of extractives and holocellulose is after the 21st year, while for lignin after the 5th year.

摘要

本研究的目的是评估合理利用入侵物种天树 ( Ailanthus altissima ) 的木材和树皮的潜力(Mill.) Swingle)，通过他们彻底的化学表征。使用湿化学分析/提取，检查了不同树木部分的木材和树皮材料的提取物、纤维素、半纤维素、木质素和灰分含量。研究了从髓到形成层的茎干化学成分的水平变异性，以及早材和晚材之间的差异、不同年轮、边材和心材以及木材和树皮之间的差异。还确定了材料的平衡水分含量、密度、pH 值、颜色和热值。树皮材料呈现出比木材更高的提取物、略高的木质素、高得多的灰分和略低的全纤维素含量。随着树龄的增加，木材和树皮的木质素含量降低，但全纤维素和提取物呈线性增加。与边材相比，心材显示出更多的提取物、木质素和灰分，以及更少的全纤维素。非常低的灰分含量和高热值构成了对其在固体生物燃料生产中的利用非常重要的特征。提取物和全纤维素的最高可能利用率的最佳收获时间是第 21 年之后，而木质素的最佳收获时间是第 5 年之后。