CARBON STORAGE IN AFROMONTANE RAIN FORESTS OF THE EASTERN ARC MOUNTAINS OF TANZANIA: THEIR NET CONTRIBUTION TO ATMOSPHERIC CARBON

Abstract

With the increasing concern about rising atmospheric carbon dioxide concentration and its implications for global climate, the role of terrestrial vegetation, and especially tropical forest management have received attention as a means of mitigating carbon (C) emissions. Thus, inventorying carbon pools in these ecosystems has become important for understanding the global C budget. Tree dimensions, wood basic density and analyses of soil C concentration were used to quantify the biomass and C pools of the Eastern Arc Mountains of Tanzania. Tree C density was estimated as product of wood volume, basic density, and proportion of C in wood. Soil C density was estimated as product of soil volume, bulk density and per cent C. Tree biomass was 1055 + 35 and 790 + 20 t ha^-1 for the Usambaras and Ulugurus respectively. These aggregated to 517 + 17 t ha^-1 C in the Usambaras and 388 + 10 t ha^-1 in the Ulugurus. The soil organic C density was 418 + 100  t ha^-1 in  the  Usambaras  and 295 + 53 t ha^-1 in the Ulugurus. Mid-altitude plant  communities  had  higher  C storage potential compared with high altitude plants. This capacity for C storage, population pressure and the exte nsiveness  of  these  forests  in  the  region  make their conservation a global significance for C emission mitigation.