Above-ground Biomass Allometric Equation and Dynamics Accumulation of Eucalyptus Camaldulensis and Acacia Hybrid Plantations in Northern Thailand

In order to supply biomass energy in Thailand, fast-growing trees like Eucalyptus and Acacia are large plantations in the region. However, there are few studies on related topics such as biomass growth versus time and tree partitioning. The objectives of the study are to develop biomass equations and characterize biomass dynamics accumulation for E. camaldulensis , E. camaldulensis coppice, and A . hybrid. The study plantation area is 960 hectares in Lampang and Lamphun province, Northern Thailand. The planted density is 1666 trees ha -1 . A total of 221 trees for destructive sampling were randomly selected from thirteen sites. Allometric biomass equations for tree components are developed by regressing the diameter at breast height (DBH), tree height (H) and a combination of these. The results show that DBH alone is an optimal predictor variable for all studied species. However, the combination of DBH and H is more accurate than DBH alone. The models show that the total estimated above-ground biomass (AGB) production is 62.78 t ha -1 and 48.87 t ha -1 at the age of 5 years of E. camaldulensis and A . hybrid, respectively. The total estimated AGB production of E. camaldulensis coppice is 18.21 t ha -1 at 3 years of age. The equations developed in the study can be used to estimate the growth of the three species under the same growing conditions: topography, tree growth dimensions, and plantation density.