QUANTITATIVE ASSESSMENT OF TREE SPECIES AND WOOD VOLUME USED IN THE PRODUCTION OF FIRED CLAY BRICKS: THE CASE OF ZOMBA DISTRICT

Abstract

Most of the buildings constructed in Malawi use burnt bricks. This study investigated tree species used for burning bricks in Zomba district because fired clay bricks depend on fuel wood which has exacerbated deforestation in the district. Parameters investigated included determination of plant species, Calorific Value (CV) of the same and volume of wood used in the process. Names of species were verified by taxonomists from NHBG, Calorimetry was used to determine CV, whilst Huber’s formula was used to quantify volume of wood. Results indicate that 33 different tree species were used for burning bricks of which 25 were indigenous and 8 exotic. Pterocarpus rotundifolius (Sond) (Bleeedwood tree) had the highest CV of 53,705,934.735 J/Kg whilst Newtonia buchananii (Baker) (Forest newtonia) recorded the lowest CV of 43,576,691.89 J/Kg. Wood volume for both exotic and indigenous was more or less the same at 10.6 m3 and 10.8 m3 respectively though indigenous species outnumbered exotic species. There is a misconception that indigenous species have higher CV than exotics, however that is not the case from this study. It is thus imperative that communities are made aware of indigenous and exotic tree species with higher CV. Promoting propagation and sustainable use of such species will be a positive step in combating deforestation in the country.