African blackwood (ABW) (Dalbergia melanoxylon) mainly occurs in the coastal areas of East Africa, including in Tanzania and Mozambique, and its heartwood is commonly known to be one of the most valuable materials used in the production of musical instruments. Although the heartwood is one of the most expensive timbers in the world, very low material yield has recently resulted in the significant reduction of natural individuals. This might have serious impact on local communities, because this tree is apparently the only species that can support their livelihood. Therefore, a solution to the problem is urgently needed in terms of the sustainable development of communities. In this study, we survey environmental factors (stand structure and soil properties) in the Miombo woodlands of southern Tanzania, where ABW was once widely distributed, to clarify the factors affecting growing conditions of ABW. Three community forests located in Kilwa District, Lindi, Tanzania, were selected as the survey sites, and 10-13 small plots (0.16 ha/plot) were randomly established at each site. In addition, the stem qualities of standing trees were evaluated by visual inspection rating and a non-destructive measurement of stress-wave velocity, for understanding the relationship between environmental factors and growth form. It was found that ABW was widely distributed under various environmental conditions with intensive population, and that their growth form depended on environmental factors. Since there was no significant difference of stress-wave velocities among the site, our findings suggest that the dynamic properties of ABW trees does not depend on growth conditions, which is generally influenced by various external factors. These results present important information regarding the sustainable forest management of ABW.

African blackwood (Dalbergia melanoxylon) is known as an indispensable material for the production of musical instruments, e.g., clarinets, oboes, and piccolos. The authors focused on the biological performance of African blackwood and other local Tanzanian species in order to collect preliminary data for developing further uses for these local timbers. Five local species, including African blackwood, were exposed to both subterranean termites (Coptotermes formosanus) and two wood decay fungi (White rot fungus (Trametes versicolor) and Brown rot fungus (Fomitopsis palustris)) according to Japanese standard test methods. African blackwood heartwood had high durability against both termite and fungal attacks, as well as the highest air-dried density of all test species. Some species also indicated a higher durability, even though they had a lower density than African blackwood heartwood. The authors showed the importance of heartwood extractives in terms of biological performance for the local Tanzanian timbers. The authors findings suggested that African blackwood heartwood was clearly useful as a high-durability material in addition to current major applications. The potential of the other local species was also suggested in terms of further timber utilization. These results presented fundamental information about sustainable forest management based on the effective utilization of local timbers.

The efficacy of decompression treatment as a non-destructive method to control larvae of the powderpost beetle, Lyctus africanus Lesne, was evaluated in the laboratory using various combinations of two pressure levels, 1.1 kPa and 40 kPa, and three temperature levels, 20, 25, and 40 °C. Larval mortality generally depended on weight reduction while decreases in the oxygen level had relatively little effect. The lower pressure, 1.1 kPa, significantly affected mortality, and no larvae survived after 12 h of this pressure treatment, at 25 °C. The average body weight was reduced with treatment time and temperature, and the reduction rate at 25 °C was higher than that at the lower temperature, 20 °C. Effects on larvae of the higher pressure treatment, 40 kPa, with a CO2 gas purge, were tested to determine the feasibility of decompression treatment in the manufacturing process. Although higher pressure resulted in low mortality, the body weight was dramatically decreased using the CO2 purge. These results present important information on the possibility of using decompression treatment for wood products.

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