Estimation of aboveground tree carbon stock in smallholder forests of the southern highlands, Tanzania

Abstract

Allometric models for estimating carbon under small holder forests differ depending on tree species, site, and tree components. The study was carried out to develop specific allometric models and quantify the aboveground carbon stocks for Pinus patula and Eucalyptus saligna in Mbozi and Mufindi Districts. The results showed that allometric models that use DBH as the,predictor variable were the best in predicting aboveground carbon stock for tree components in smallholder forests. Using the component model the carbon density for Eucalyptus saligna in Mbozi amounts to 23.50 t C ha-1 and in Mufindi it was 41.34 t ha-1. Pinus patula in Mbozi had carbon density amounting to 49.43 t C ha-1 while it was 36.96 t C ha-1 in Mufindi. These amounts translate into 86.25 t ha-1 of C02e in Eucalyptus saligna stands in Mbozi and 151.72 t ha-1 in Mufindi. Further, Pinus patula stands stored 181.41 t ha-1 and 135.64 t ha-1 of C02e in Mbozi and Mufindi respectively. By using total tree model the-carbon density for Eucalyptus saligna in Mbozi amounts to 2.36 t C ha-1 and 10.29 t ha-1 in Mufindi. Pinus patula in Mbozi had 45.05 t C ha-1 while in Mufindi it was 33.96 t C ha-1 • The amounts translate into 8.67 t ha-1 of C02e in Eucalyptus saligna in Mbozi and 37.76 in Mufindi. On the other hand Pinus patula had 165.32 and 124.63 t ha-1 of C02e in Mbozi and Mufindi respectively. It is apparent that there is a high potential for climate change mitigation through carbon accumulation under smallholder forestry.