Carbon Stocks of Homestead Forests Have a Mitigation Potential to Climate Change

Abstract

Homestead forests of Bangladesh (0.27 million ha land) have potential of providing co-benefits of conserving biodiversity and storing carbon (C). The study aimed to estimate C stocks and how stand structure affects the tree biomass C in homestead forests of the Chittagong Hill Tracts (CHT), Bangladesh. A total of 176 homestead forests at three altitudes in the CHT were randomly surveyed. All woody vegetations were measured, and litter and soil (0–30 cm depth) were sampled. The results show that the above- and below-ground tree biomass C stock in the top two altitude forests was up to 37-48% higher than in low altitude, due to significantly higher tree density and species diversity. An increase in species diversity index by one unit increased the biomass stock by 23 Mg C ha 1. The C stock of litter fall in low altitude forests was 22-28% higher than in the top two altitude owing to the deposition of litters downslope by gravity and deliberate use of pruned materials as mulch for soil improvement and conservation, resulting in up to 5% higher total soil C. The topsoil C was 10–25% higher than the deeper soil, depending on the altitude. The forest stored a total of 71 tree species and 89 Mg C ha1, which can contribute to climate change mitigation while conserving biodiversity, moisture, and hill soil in small-scale forests. This study would help policymakers to strengthen the recognition of small-scale forests for mitigation in REDD+ (reducing emissions from deforestation and forest degradation, the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks) by generating C credits for owners from sustainably managed forests.