Potential of using tree height as a surrogate variable to estimate biomass and total organic carbon of mangrove trees

Abstract

Estimation of biomass and total organic carbon (TOC) content in mangrove plants/species presents a realistic measure of the carbon sequestration capacity of plants/species in these communities. Allometric models are widely used for estimating biomass and TOC, and are considered sufficiently a reliable tool in tree biomass estimation. Although diameter at breast height (dbh) is the commonly used quantifiable variable to develop allometric models to estimate biomass, it requires accessing each individual plant to measure the dbh, which often can be a cumbersome task, particularly when it has to be performed in a muddy and waterlogged conditions in a remote location. Twenty-one (21) individuals of Bruguiera gymnorrhiza, and 20 individuals of Lumnitzera racemosa trees were selected to represent the range of dbh of the respective species that occurred in the mangroves at Kadolkele in Negombo estuary, Sri Lanka. A statistically significant relationship (p<0.001) was revealed between the tree height and dbh of both species. TOC content embedded in biomass was calculated using published data. Allometric relationships were developed between biomass/TOC and height of B. gymnorrhiza and L. racemosa. The accuracy of estimated biomass of allometric relationships was compared with the actual data set and revealed more than 95% and 93% of reliability for above-ground biomass and below-ground biomass, respectively. Instead of dbh, tree height, which is measurable from distance with suitable remote sensing tool, may be used reliably to estimate the stand biomass of mangroves that cannot be accessed easily on foot.