Biomass expansion factor and root-to-shoot ratio for Pinus spp. in southern Brazil

Abstract

Biomass expansion factor (BEF) and root-to-shoot ratio (R) are variables for quantification of carbon in forests. These are considered as constant values in most studies. 70 sample trees were used to BEF and R, and DBH, tree height and age. Dry total biomass, carbon and CO2 equivalent were simulated by using the IPCC default values of FEB and R, corresponding average calculated from data using in this study and as well as the values estimated by regression equations. The values of FEB=1.47 and R=0.17 in this study means that 47% of total biomass corresponds to tree crown and 17% of it comprises tree roots or below-ground biomass. The correlation BEF and R with tree DAP, H and age were significant. Some equations to FEB and R as functions of the tree variables revealed better performance than others, as they fitted better. The simulations indicated that use of fixed values of BEF and R, either IPCC default or average actual data may lead to unreliable of carbon and CDM projects. As result, FEB and R use in regression equations relating them to DBH, tree height and age are fundamental to get reliable estimates of tree biomass, carbon sink and CO2 equivalent.