Forest fires are becoming larger and are happening more frequently as a direct result of rural depopulation, rather than being a direct result of climate change.
The research – conducted by scientists from Universidad Carlos III de Madrid (UC3M) in Spain, and published in the journal Climate Change – looked at over a 130 years of fire data from Valencia, Spain and found that as the population moved from rural areas to the city during the 1970s the availability of burnable material increased, subsequently increasing the size and frequency of fires.
The scientists – Professor Santiago Fernández Muñoz from UC3M and ecologist Juli Pausas from is Consejo Superior de Investigaciones Científicas (CSIC – Spanish National Research Council) – looked back through newspapers and other sources in Valencia to 1875 and built a database of every fire that was mentioned.
This furnished them with a complete database of thousands of records of fires identified by date, location, and the amount of surface area that it had burnt through.
They then related this statistical information with socioeconomic variables (evolution of the population, land use, etc.) and climatic variables (precipitation, temperature) to determine the most likely causes.
They found that the size and frequency in fires grew during the 1970s as residents in the country headed city-ward, leaving the rural land behind them to transform.
“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.
Additionally, due to the increase in other means of heat and electricity generation, extraction of firewood decreased dramatically which saw the forests start stretching further without interruption from agriculture.