BIOMASS EXPANSION FACTORS IN TEMPERATE FOREST COMMUNITIES OF NORTH DURANGO

Abstract

Forest biomass is generally quantified in kilograms of green or dry weight per tree or in tons per area. It is an environmental key element to assess the carbon amounts that can go to the atmosphere or be fixed when these ecosystems are managed to mitigate the greenhouse-effect gases. This research was conducted in northern Mexico in order to assess the biomass components and biomass expansion factors, with the use of alometric component equations and the classical physics equation that uses wood specific gravity applied to forest inventory data. Field and laboratory recorded data consisted on fresh and oven dried weight of stem and branch components. Biomass estimations were conducted following two procedures: 1) using an alometric equation that feeds with normal diameter and 2) employing the wood specific gravity times volume. Once biomass was estimated at the stand level it was divided by stand volume derived from inventory data to calculate the biomass expansion factors. The results showed differences in methods of estimating biomass and therefore in expansion factors as well. Biomass expansion factors are dependent on the mean top height of trees and wood specific gravity. These parameters are normally distributed for the inventory data utilized.