Improving biomass estimation for Eucalyptus globulus Labill at stand level in Portugal

The proposed equations where used on National Forestry Inventory plot data and the results obtained where compared to the inventory results and estimates obtained using tree level allometric equations and Biomass Expansion Factors (BEF's). The comparison of the four approaches showed that the use of stand level methods gives as accurate results as the use of tree level methods. The use of BEF's resulted in the least accurate method for estimating biomass, with an average mean error of 17%. In contrast, the proposed equations estimate biomass values with a mean error of 9% and are the best option for biomass estimates in short rotation forestry, where the objective is to obtain biomass estimates for short rotation stands (2-5 years). They also allow tree component biomass estimates, something that is not possible using the existing BEF's for Eucalyptus globulus.