Allometric equations for estimating biomass in four poplar species at Charmahal and Bakhtiari province

Carbon sequestration into plant biomass is an easiest and economically most practical way for dropping off CO2 from atmosphere. The current study was made for four poplar species, consisting of two natives (Populus alba and P. nigra) and two exotics (P. alba×euphratica and P. euphratica× alba), planted at Boldaji Experimental Station in province of Charmahal and Bakhtiari of I.R. Iran. Tree sampling was made randomly (10 trees for each species). After measuring the tree's characteristics including diameter at breast height (dbh), total height and crown diameter, they were felled down to measure the dry weight of different organs, including: (whole tree, trunk, main branches, twigs, leaf and bark of twigs and branches). The regression analysis was applied to find out relationships between mass production and poplar characteristics and to develop different allometry models between different organs and their carbon sequestration ability. The results showed that there are significant correlations to predict biomass for the whole tree's organs at each species. The independent dbh values, in Populus alba and P. alba×euphratica demonstrated high correlation against all the dependent variables (R2=0.95). On the other hand, the main trunk weight was significantly correlated to bark weight (R2=0.86), showed high accurate models. In P. nigra and P. euphratica × P. alba, due to forked stems, dbh didn’t prove any correlation with the tree's characteristics. At the same species, on the other hand, crown diameter was correlated to carbon sequestrated amount on all portions of the trees (R2=0.88). The research showed also significant priority of woody organs in comparison to leaf and twigs, when the prediction of the carbon storage is scheduled