Estimation of aboveground biomass in mangrove forests using high-resolution satellite data

Mangroves play important roles in providing a range of ecosystem services, mitigation of strong waves, protection of coastlines against erosion, maintenance of water quality, and carbon sink in the context of global warming. For trees in mangrove forests in southern Ranong Province, Thailand, we investigated the allometric relationship between crown area derived from high-resolution satellite data and stem diameter and used the resulting model to estimate aboveground biomass. We used QuickBird panchromatic and multispectral data acquired for the study area on 15 October 2006 as the high-resolution satellite data. Individual tree crowns were extracted from the satellite image of panchromatic data by using the watershed method, and the species were identified by using the maximum-likelihood method for the multispectral data. Overall classification accuracy for species identification was 88.5 %. The biomass derived from our field survey was plotted against aboveground biomass in the sample plots, estimated from the QuickBird data. The regression line through the origin between the satellite-estimated biomass and biomass based on the field data had a slope of 1.26 (R ² = 0.65). Stand aboveground biomass estimated from the high-resolution satellite data was underestimated because of a lack of data on the biomass of suppressed trees and inappropriate segmentation of crowns of large trees into two or more trees.