From woodfuel to industrial wood: A socio-metabolic reading of the forest transition in Spain (1860–2010)

After centuries of deforestation, many, mostly industrialized countries have recently been experiencing net increases in forest area and biomass stocks, a phenomenon described as ‘Forest Transition’. In this article, we analyse the Spanish forest transition over the last 150 years from a socio-metabolic perspective. We provide the first estimation on forest surface, wood production and biomass stocks and we relate these changes to the socio-metabolic transformations of Spain's economy. Between 1860 and 1950, within a context of organic metabolism and growing population pressure, the stock of forest biomass decreased by 25.3%, falling to its lowest level in c. 1950. By conducting a decomposition analysis, we show that deforestation (i.e., declining forest area) explains 33.7% of the decrease in stock, while the reduction of biomass density accounts for 66.3%. Since 1950, and coinciding with the industrial socio-metabolic transition, forest biomass stocks multiplied by a factor of 2.5. Cropland intensification, the outsourcing of land use to third countries and agricultural policy encouraged the expansion of forest areas. Nevertheless, the substitution of firewood with fossil fuels was the main explanatory factor of the stock increase, since it enabled a dramatic decline in wood appropriation and the consequent increase in biomass density.