Study in a beech stand of Centra1 Italy: allometric relations for the above ground biomass estimation

Abstract

Proxy equations estimating above ground biomass are discussed. Data were collected in three pure evenaged beech stands in the Tosco-Emiliano Appennine. The sample was extracted by ranking the tree populations per diameter at breast height (d) and social position; crown and stem modules were separeted and measured directly in the field or by laboratory analysis. The crown of each sample tree was measured at single branch leve1 and recomposed by using regression equation validated from a set of 178 sample branches. The best allometric relations for the estimation of the above ground biomass are exposed as well as those related to the elementary samples (water content, bark thickness, diameter increment, leaf characteristics). Stepwise method has been utilised in order to find the number of variables in the equations; bilogaritmic mode1 ever performed the best fitting. Stem and branches biomass can be predicted by the combination of d and h: the latter with a lower accuracy rate. Leaf dry biomass can be forecasted by using d and a crown variable (such as crown depth or crown insertion height); nevertheless the standard error of estimate results rather high.