Modeling Mangrove Above-Ground Biomass Using Terrestrial Laser Scanning Techniques: A Case Study of the Avicennia marina Species in the Bang Pu District, Thailand

Deterioration of tropical mangrove forests is one of the most serious problems of the world's coastal ecosystems. Mangrove above-ground biomass (AGB) modeling is the key to support the management and rejuvenation of these ecosystems. Nevertheless, it is illegal to observe tree data using the destructive methods in reserved mangrove forests for acquiring tree allometric models. Thus, this study proposed a non-destructive alternative, the use of a terrestrial laser scanner (TLS) technique. The study site dominated by Avicennia marina (Forsk.) Veirh (A. marina) was located in the Bang Pu conservation area, Thailand. The tree structures were quantified and tested in this study. A Quantitative Structural Model (QSM) was chosen for the calculation of the tree stem volume. Then, the TLS allometric model was generated via a power function. The RMSE between the presented model and the four reference A. marina models were reported in this study. The largest RMSE errors (i.e., 40% and 35%) were found when comparing the TLS allometric model to the two generic allometric models. On the other hand, the outcomes of the species-specific models were closer to the outcome of this study (i.e., the RMSE errors are less than 20%). The disagreement between the proposed TLS model and the generic mangrove model suggested that a species-specific model is needed for more accurate results. It is anticipated that the methodology presented in this study may be used as standard procedures for producing the A. marina allometric model in other areas.