Exploration of the aboveground carbon sequestration and the growth estimation models of four species in agroforestry system of semi-arid region, Myanmar

Carbon sequestration in agroforestry systems plays an important role for climate change regulation. Policy makers make use of growth models for carbon estimations of the large scale projects in designing regulation. This study revealed the aboveground carbon sequestration potentials and established allometric growth models of four species in agroforestry. Based on the results, the aboveground carbon storages of Morinda tinctoria Roxb., Terminalia oliveri Brandis., Rhus paniculata Wall. and Emblica officinalis Gaertn. were 6.88, 6.59, 4.34 and 3.53 kg C tree⁻¹, respectively. In comparison between two types of agroforestry, a mixture of M. tinctoria and E. officinalis had a higher carbon sequestration potential (1331 kg C ha⁻¹) than a mixture of R. paniculata and T. oliveri (1151.40 kg C ha⁻¹). A hyperbolic growth model and a basic quadratic model were the best-fit models for R. paniculata and E. officinalis, respectively, while a basic logarithmic model was the best fit for both M. tinctoria and T. oliveri. This study highlighted that both Akaike Information Criterion, Furnival index and coefficient of determination should be taken into consideration for model selection, as opposed to only considering the coefficient of determination. The study also pointed out that a mixture of M. tinctoria and T. oliveri should be considered as a tentative model for agroforestry plantations to enhance the carbon storage in semi-arid area in the future.