Forest fires are becoming larger and more frequent

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http://www.uc3m.es/portal/page/portal/actualidad_cientifica/noticias/forest_fires

Forest fires are becoming larger and more frequent

Research in which scientists from Universidad Carlos III de Madrid (UC3M) are participating analyzes the causes and characteristics of fires that have occurred in the Mediterranean basin in recent decades, and determines that rural exodus and changes in land use have increased the number and size of these fires.

The study, recently published in the journal Climatic Change, is the result of an interdisciplinary collaboration between two researchers: one is UC3M Professor Santiago Fernández Muñoz, who has worked in the area of geographic history under the direction of the Universidad Autónoma de Madrid Professor Josefina Gómez Mendoza; the other is Consejo Superior de Investigaciones Científicas (CSIC – Spanish National Research Council) ecologist Juli Pausas. Specifically, the authors constructed a complete database of historical fires in the province of Valencia in order to relate them to the evolution of the climate and societal and territorial transformations in the region. The research that was carried out provides the most complete series of data on the evolution of fires in the Mediterranean basin to date.

The conclusion they have reached is that a significant change in the number and, especially, size of forest fires took place during the decade of the seventies. This change can be directly related to the rural exodus and transformation of land use that took place during that decade. "The depopulation of rural areas resulted in the abandonment of agricultural spaces that had historically been interspersed among the forests. Because of this, in the space of a few years, spaces where there had previously been grain fields were invaded by highly flammable vegetation in a series of steps leading toward the Mediterranean forests", explains Professor Fernández Muñoz.

The key: 0,6 inhabitants per square kilometer

At the same time, the extraction of firewood decreased drastically as a consequence of the incorporation of other sources of energy, and the country witnessed a very relevant transformation in its rural landscapes, which became “less populated and with fewer patchworks of land for agricultural use, with more continuous forest masses and more highly flammable vegetation", clarifies the expert. In spite of the fact that depopulation and the changes in land use were gradual, this research has detected a number of thresholds after which a very significant increase in the number of fires took place; these numbers fall around a population density of 0,6 inhabitants per square kilometer.

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http://dx.doi.org/10.1007/s10584-011-0060-6