Regional Environmental Change

, Volume 14, Issue 4, pp 1395–1404

Two thresholds determine climatic control of forest fire size in Europe and northern Africa

Original Article

DOI: 10.1007/s10113-013-0583-7

Cite this article as:
Loepfe, L., Rodrigo, A. & Lloret, F. Reg Environ Change (2014) 14: 1395. doi:10.1007/s10113-013-0583-7


Fire weather indices predict fire extent from meteorological conditions assuming a monotonic function; this approach is frequently used to predict future fire patterns under climate change scenarios using linear extrapolation. However, the relationship between weather and fire extent may potentially depend on the existence of fuel moisture content thresholds above which this relationship changes dramatically, challenging this statistical approach. Here, we combine the continuous and the threshold approaches to analyze satellite-detected fires in Europe during 2001–2010 in relation to meteorological conditions, showing that fire size response to decreasing fuel moisture content follows a ramp function, i.e., with two plateaus separated by a phase of monotonic increase. This study confirms that at continental and high-resolution temporal scales, large fires are very unlikely to occur under moist conditions, but it also reveals that fire size stops to be controlled by fuel moisture content above a given threshold of dryness. Thus, fuel moisture content control only applies when fire is not limited by other factors such as fuel load, as large fires were virtually absent during the considered period in dry regions with less than 500 mm of average annual precipitation, i.e., low-productive areas where fuel amount would be scarce and discontinuous. In regions with sufficient fuel, other factors such as fire suppression or fuel discontinuity can impede large fires even under very dry weather conditions. These findings are relevant under current climatic trends in which the fire season length, in terms of number of days with drought code values above the observed thresholds (break points), is increasing in many parts of the Mediterranean, while it is decreasing in eastern Europe and remains unchanged in central Europe.


Fire size Remote sensing Threshold Ramp function Fire weather 

Supplementary material

10113_2013_583_MOESM1_ESM.docx (43.7 mb)
Supplementary material 1 (DOCX 44772 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Lasse Loepfe
    • 1
  • Anselm Rodrigo
    • 1
    • 2
  • Francisco Lloret
    • 1
    • 2
  1. 1.Center for Ecological Research and Forestry Applications (CREAF)Universitat Autònoma de BarcelonaBellaterraSpain
  2. 2.Unit of Ecology, Department of Animal Biology, Plant Biology and EcologyUniversitat Autònoma de BarcelonaBellaterraSpain

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