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Effects of tree thinning on carbon sequestration in mangroves
Mangrove overgrowth could decrease biodiversity and increase flooding risk. Thinning has been proposed as a managerial action, which would decrease their capacity for carbon sequestration. This study was aimed to examine the relationship between differences in mangrove tree density and carbon sequestration capacity. We established three sampling sites in the Fangyuan mangroves of Taiwan, including seaward and landward sites with Avicennia marina and a site with Kandelia obovata, with control (C, no thinning), medium thinning (MT, 50% thinning) and high thinning (HT, only one tree left at the center) treatments. The HT treatment significantly reduced the areal carbon sequestration rates (66-84%), but the reductions in the MT treatment were much lower (3-30%). Considering the carbon sequestration per tree, the HT treatment resulted in the significantly highest rates (2-5 times higher) than those under the MT and C treatments. Medium thinning appears to be the optimal strategy to meet the demands of reducing the loss of carbon sequestration capacity for mangrove management. Combined the data obtained in this study and derived from the relevant literature, the relationships suggest a maximum level of carbon sequestration by managing density of 30600 trees ha-1 for K. obovata or 10500 trees ha-1 for A. marina.
MF17151 Accepted 23 September 2017
© CSIRO 2017