Mozambique’s large pool of tropical hardwoods is hampered by the prevalence of low-grade tree species along with a lack of cost-effective processing technologies to improve timber properties. Brachystegia spiciformis and Julbernadia globiflora are the most abundant tree species in terms of volume in the country, but with limited use due to their low timber quality. In this study, thermal modification at three different temperatures (215 °C; 230 °C; 245 °C) was applied for 2 h to the timber of both species, followed by measurement of a set of physical and mechanical wood properties. The results show that the originally light-coloured sapwood of both tree species darkened gradually as the intensity of thermal modification increased. Additionally, from untreated samples to the highest thermal treatment level, timber of B. spiciformis incurred a maximum mass loss of 27%, while oven-dry density was reduced from 0.65 to 0.56 g/cm³ and equilibrium moisture content (EMC) changed from 7 to 3%. Timber of J. globiflora had a mass loss of 23% after the highest treatment level, an oven-dry density reduction of 0.81 to 0.74 g/cm³ and an EMC decrease from 8 to 3%. The changes in mechanical properties from reference samples to the highest thermal treatment level were also significant. For B. spiciformis, MOE decreased by 10.2%, MOR by 50.8%, compression strength parallel to the grain by 29.2% and Brinell hardness by 23.5%. Timber of J. globiflora followed the same trend with an MOE decrease by 6.9%, an MOR decrease by 53.2% and a decrease in compression strength parallel to the grain by 21.9%. All tested wood properties showed significant responses to thermal modification after the most intensive treatment level had been applied. Despite the degradation of mechanical properties in both species, an optimal combination of temperature and treatment time could be achieved. The recorded changes of the tested wood properties in both species could increase the range of applications; the new colour resembled that of highly sought-after tropical hardwoods.

莫桑比克大量的热带硬木被低级树种的盛行以及缺乏提高木材特性的经济有效的加工技术所困扰。Brachystegia spiciformis和Julbernadia globiflora从数量上讲，它们是该国最丰富的树种，但由于其木材质量低而使用有限。在这项研究中，对两种物种的木材在三种不同温度（215°C； 230°C； 245°C）下进行了热改性2小时，然后测量了一组物理和机械木材性能。结果表明，随着热改性强度的增加，两种树种的原始浅色边材逐渐变黑。此外，从未经处理的样品到最高热处理水平，芽孢杆菌的木材最大质量损失为27％，而烘箱干燥密度从0.65降低至0.56 g / cm ³，平衡水分含量（EMC）从7至3％。globiflora的木材在最高处理水平后，其质量损失为23％，烘箱干燥密度降低0.81至0.74 g / cm ³，EMC降低8％至3％。从参考样品到最高热处理水平的机械性能变化也很显着。对于芽孢杆菌，MOE降低了10.2％，MOR降低了50.8％，平行于谷物的抗压强度降低了29.2％，布氏硬度降低了23.5％。globiflora的木材遵循相同的趋势，MOE下降6.9％，MOR下降53.2％，平行于晶粒的抗压强度下降21.9％。在采用最严格的处理水平后，所有测试的木材性能均显示出对热改性的显着响应。尽管两个物种的机械性能均下降，但仍可以实现温度和处理时间的最佳组合。在两个物种中记录的经测试的木材性能变化可以扩大应用范围；新颜色类似于备受追捧的热带硬木的颜色。