Above-ground tree biomass equations and nutrient pools for a paraclimax chestnut stand and for a climax oak stand in the Sierra de Francia Mountains, Salamanca, Spain

Abstract

Above-ground tree biomass and total amounts of nutrients in biomass were estimated at two plots: the first in a Castanea sativa Mill. paraclimax coppice and the second in a Quercus pyrenaica (Wild.) climax forest, both of them located in the south of the Salamanca (Spain), by harvesting 10 trees at each plot. In order to obtain the best fit possible, for these analyses, four regression equations were applied: linear, logarithmic, potential and exponential. In the chestnut coppice, the best fits were obtained using the exponential regression, while for the oak plot the best fit was obtained with the linear regression. A parametric analysis was also performed for each fraction of the tree biomass between both plots. This revealed that, total biomass and that of the trunks, branches and leaves at the chestnut coppice were significantly greater than those found at the oak plot. At the chestnut coppice for the nutrients (except carbon) significant differences were observed between leaves, branches and trunks, the highest concentrations being found in the leaves, followed by the branches and the trunks. This order was also observed at the oak plot, with the exception of calcium, which did not reveal significant differences between the branches and the trunks. Key words: Above-ground biomass, allometric method, nutrient storage, forest ecosystems, Castanea sativa, Quercus pyrenaica.