Diversity, structure, and carbon storage of Rau catchment forest reserve in Moshi District, Tanzania

Abstract

The effects of anthropogenic activities and the dominance of exotic tree species on the Rau Catchment Forest Reserve (RCFR) in Moshi District, northern Tanzania, have been poorly documented. This study assessed (i) the current status of species composition, stand structure, and diversity, (ii) threats to biodiversity posed by anthropogenic activities and exotic tree species, and (iii) the carbon stock of RCFR. Data were gathered from 45 circular sample plots, identifying 29 woody plant species. The forest exhibited high woody species diversity (H’=2.91), with a density of 185±81 stems ha-1, a standing volume of 405.75±227.16 m3 ha-1, and a basal area of 23.05±12.37 m2 ha-1. Evidence of human activities, particularly tree cutting and the dominance of exotic species, was prevalent, with illegal harvesting affecting 23 species. The mean above-ground and below-ground carbon stocks were estimated at 107.48±61.28 Mg C ha-1 and 21.50±12.26 Mg C ha-1, respectively. The high diversity of woody species suggests that the forest may be recovering from past illegal logging. However, the increasing dominance of exotic species highlights the urgent need for measures to control their spread.