ECOLOGICAL EFFECTS OF HARVESTING BIOMASS FOR ENERGY IN THE SPANISH MEDITERRANEAN

Biomass utilization for energy has major consequences for Spanish Medi terranean landscapes. In this paper we present a synthesis of the ecol ogical effects of harvesting biomass for energy. We compare these effe cts with other fuel reduction procedures such as prescribed burning. T hroughout history we see that some Iberian ecosystems are stabilized b y long human interference. One of the stabilizing factors is the utili zation of wood as a source of energy. New energy sources and massive h uman movements towards urban areas have changed the ecosystem dynamics . Reforested areas in Spain during the period from 1940 to 1970 includ ed silviculture treatments that in some cases never took place. This h as led to a greater accumulation of biomass. The current perspective o f the problem must be analyzed from an economic and political viewpoin t. For instance, the Middle East crisis has direct consequences for th e budget dedicated to forest energetics, and consequently for the land scape. This shows how ecological problems must be dealt with using a v ery broad perspective. In Spain current biomass usage should be consid ered primarily as a complementary silvicultural treatment rather than as a way of producing great biomass outputs. If we are going to manage our forest from an ecological perspective, we have to analyze the eff ects of these operations at the stand level. At the landscape level fu el management plans should be included in the Forest Management Prescr iptions (ordenaciones) whether in terms of harvesting or in a prescrib ed burning plan.