Temporal (1958-1995) pattern of change in a cultural landscape of northwestern Portugal: implications for fire occurrence

In this paper we test the hypothesis that landscape changes in a region of Northern Portugal (Minho) in the last 40 years could be predicted from socioeconomic and political history. The major predicted changes were related to agricultural abandonment and afforestation. We further predicted that these changes contributed to increased fire risk. Analysis of aerial photography for the years 1958, 1968, 1983 and 1995 in a study area of 3700 ha revealed a significant decline in agricultural areas and low shrublands and an increase in tall shrublands and forests. This represented a 20-40% increase in fuel accumulation at a landscape level, suggesting that the abandonment of farming activities is a major driving force of increasing fire occurrence in the region. With one exception, all the predictions were partly or totally confirmed. This study confirms that socioeconomic factors might explain a significant part of the variation in landscape composition across time, in the Mediterranean region.