Effect of Thinning on Carbon Stocks in Sonneratia apetala Buch.-Ham Plantations: a Simulation Study

Abstract

Abstract Background Forests are very important for sequestering atmospheric carbon, and mangroves are amongst the most efficient carbon-sequestering ecosystems. In Bangladesh, several plantations of Sonneratia apetala have been raised, with large-scale plantations along the coastal belt. An individual-based model (KiWi model) was developed in order to analyze demographic processes in mangrove forests according to abiotic environmental factors, individual tree spacing, local tree-to-tree interactions, and intra-specific competition. In this study, we selected several silvicultural approaches (with or without thinning and with or without recruitment) to compare the development of planted forests in terms of forest management. Data obtained from the field monitors the output and parameterization of the model. Thinning normally avails more space and thus resources for growth, which leads to enhanced biomass increment. The objectives of this study were to identify the short-and long-term effects of thinning on carbon stocks in a mangrove plantation. Simulation experiments, tuned to observe the configurations of the study sites, provided a forecast of the stand development to be expected in the future. Results In this study, two thinnings were done at 15 and 20 years with a 0.5 m to 4.5 m radius while the annual sapling recruitment rate was kept at zero during thinning. Among the different thinning radii, 3.5 m radius thinning shows maximum aboveground carbon stocks in Sonneratia apetala, which is comparable to the 1.8 m stick radius thinning practised in Matang Mangrove, Malaysia for Rhizophora apiculata. In the case of Bangladesh coastal plantation, 2.5 m and 3.0 m thinning radius are perfect because 2.5 m and 3.0 m thinning radius contain an adequate number of trees and also produce above-ground carbon as much as 3.5 m thinning radius. Conclusions This experiment strongly supports that the KiWi model can mimic real dynamic growth patterns and thinning has an effect on carbon stock Simulation experiments, tuned to observe configurations of the study sites, provided a forecast of the stand development to be expected in the future.