Biomass and carbon accumulation in Northern Bangladesh Eucalyptus plantations: Effects of stand structure and age

Abstract

Eucalyptus plantations are a significant carbon sink as a fast-growing species in Bangladesh, but little is known regarding biomass, carbon output, and dynamics with stand age. We, therefore, assessed the stand structure, biomass accumulation, carbon storage, and their changing patterns with age in Eucalyptus camaldulensis Dehnh. plantations in the northern part of Bangladesh in early 2021. Biomass and carbon stocks were estimated using the allometric models specific for E. camaldulensis from the biophysical tree parameters (i.e., height and DBH). We used the data from 45 sample plots (100 sq. m each) covering different age classes such as 2, 5, 7, 8, 11, 13, and 21 years. The aboveground, belowground, total biomass, and carbon significantly varied between stand ages (p<0.05). The highest aboveground, belowground, and total carbon stocks were observed at 21 years, and the lowest was found at two years. We observed a positive and strong relationship between total carbon and stand variables such as stand height, diameter at breast height, basal area, crown width, crown length, and bole height but a negative relationship with density. The mean annual increment of both biomass and carbon increased sharply up to seven years and then decreased. Despite having some ecological constraints, E. camaldulensis accumulate a large amount of carbon from the atmosphere, perhaps aiding climate change mitigation.