INVASIVE WOODLAND RESOURCES IN THE AZORES: BIOMASS AVAILABILITY FOR 100 RENEWABLE ENERGY SUPPLY IN GRACIOSA ISLAND

摘要

The potential of biomass for energy production has been widely studied, and recently gained newrnimpetus with the attention now devoted to renewable energies. In Graciosa Island, Azores, there is a ongoing projectrnfrom Younicos AG together with the Azorean Government and the energy supplier, EDA, with the goal to achievern65% of renewable energy supply by 2016. But can biomass be used to achieve the 100% renewable energy goal? InrnGraciosa, only 12% of the land surface is forested, however, considerable land areas are occupied by alien invasivernwoodland, mostly dominated by Pittosporum undulatum Ventenat (Pittosporaceae). Field work in Graciosa was donernin order to measure P. undulatum dendrometric traits and relate these to biomass of fresh cut trees through specificrnallometric equations. Stand densities, determined by point-centered quarter method, were considerably variable,rnattaining values of up to 10,000 trees.ha~(-1). The best model for allometric equation determined wasrnln(Biomass)=a+b.ln(BasalArea2.Height)+Ɛ, with an adjusted R2 of 0.96 and AIC of 35.5. Using this equation and thernmean stand density values, the P. undulatum available biomass in Graciosa was estimated at 92,152 Mg (dry weight),rnwith an annual available biomass yield of 2,368 Mg.year-1(dry weight). The exploitation of P. undulatum biomass forrnenergetic use is viable and sustainable principles of forest management can be applied, allowing the use of thernexisting forest as well as implementing the control of an alien invasive species.