Large scale eucalypt plantations associated to increased fire risk
To satisfy the high timber demands of human society, forest plantations, especially with fast growing species like pines and eucalypts, are increasing worldwide. In some European countries, the number of wildfires has been augmenting since the second half of the XX century, in parallel with these tree plantations. The record for wildfires in Europe is paradoxically found in the NW of the Iberian Peninsula, a region where broadleaved Quercus forests are the potential climax vegetation, with a humid climate, unfavourable for fire occurrence. The ecological and forestry literature have analysed fire occurrence with complex models of fuel accumulation and vegetation structure, combined with no less complex climatic models to explain why this region has such a high fire occurrence. Economists have concentrated on the relationship between income and fire. Historians, sociologists and political scientists have long ago demonstrated that several conflicts over land use and property are behind most wildfires in this region, but there is little interaction between these fields. Here I use official statistics about fire frequency and wood production to test whether fire frequency is associated to the use of pyrophytic species. I found that fire frequency in NW Spain can be predicted by the amount of eucalypt biomass accumulated in forest plantations. I further explore the relationships between intensive sylviculture and fire risk at a regional scale (the North of the Iberian Peninsula) and a large scale, the Mediterranean countries. NW Iberia peasants have traditionally used fire to manage their common lands, and used the same techniques to oppose forest policies implemented by Franco’s dictatorship, which continued until now with little changes. The use of highly pyrophytic species like eucalypts and some pines has exacerbated this problem, as suggested by the positive correlation between eucalypt plantations and fire frequency at the local, regional and Mediterranean scales.