Fuelwood energy characteristics and biomass equations of the dominant species of northern Patagonian shrublands (Argentina)

Abstract

Although shrublands can be highly abundant, their bioenergy potential has barely been addressed. This is the case in northern Patagonian  shrublands, where there is a lack of knowledge regarding biomass quantity and quality. The objective of this study was to develop biomass  equations for young shoots (resprouts) of five of the main woody species growing in northern Patagonian shrublands; quantify energy properties of their woods and, ultimately, estimate biomass and bioenergy stocks in resprouts for three contrasting shrublands. Resprouts were harvested in the field, and size (diameter and height) and dry weight were measured in the laboratory. Fuelwood energy parameters (moisture, density, calorific value, ash content) were determined to obtain energy density and fuelwood value index. We found biomass equations with good statistical fitness for all the studied species. Energy parameters of the analysed woods were comparable or even better (in terms of energy density) than those  observed in other woody species commonly used as fuels. Embothrium coccineum showed the best fuelwood value index due to low ash content (0.2%). Shrublands under 50% of harvesting intensity produced 0.08 t ha^–1 and 1.33 GJ ha^–1 in a low productivity site, 0.34 t ha^–1 and 5.66 GJ ha^–1 in a medium productivity site, and 1.07 t ha^–1 and 17.96 GJ ha^–1 in a high productivity site from resprouts after approximately four years. This study suggests that some northern Patagonian shrublands have good potential to produce high quality biomass, therefore, sustainable management
plans oriented to bioenergy should be developed in the region.

Keywords: bioenergy, native forest, biomass models, calorific value