Fire Activity in Mediterranean Forests (The Algerian Case)

Thomas Curt,Aissa Aini,Sylvain Dupire

doi:10.3390/fire3040058

Abstract

Algeria has high wildfire activity, albeit restricted to the northern coastal fringe. However, no study has investigated why fire is restricted to that area, and what combination of factors explains the occurrence of wildfires. Here, we describe the current fire regime of Northern Algeria from 2000 to 2019 and we correlate fire activity to a range of environmental and anthropic drivers. We found a strong north–south gradient in fire occurrence: it is maximal in the high-fueled (productive) oak forests of Northern Algeria with high annual rainfall amount, whereas it is fuel-limited in the South due to semi-arid conditions. We determined that fire is nearly absent where the bioclimate is subarid or arid, due to the steppic vegetation with summer Normalized Difference Vegetation Index (NDVI) values below 0.35. Therefore, fire occupies a narrow niche in space (the humid and subhumid areas with high productivity) and in time as most fires occur in summer after the high rainfalls from fall to spring that promote fuel growth. Humans also play a role as fire hotspots are concentrated in croplands and in built-up areas with high human density and infrastructures mixed with shrublands and forests. We discuss how the ongoing climate changes and the desertification progressing towards the North of Algeria may finally restrict forests to a narrow fringe providing less and less ecological services to the Algerian people.

Highlights

Algeria is the main fire hotspot on the southern rim of the Mediterranean Basin (MB)
As the north-to-south bioclimatic gradient is preponderant in Northern Algeria, we examined fire activity together with fire danger, fuels, Normalized Difference Vegetation Index (NDVI), and the density of human assets along this gradient, in order to determine the latitudinal threshold for the presence of fire
Fire activity clearly decreases from the humid to the arid bioclimate in parallel to NDVI and precipitation, whereas the fire danger and the temperature increased over the same time

Summary

Introduction

Algeria is the main fire hotspot on the southern rim of the Mediterranean Basin (MB). Despite recent progress in the investigation of fire causes [6], fire science and policy in Algeria still lack operational models explaining the drivers of fire occurrence [7]. Fire databases are not always managed in a relevant manner [5,6], and fire danger indices are not used to assess the daily fire hazard across the country. All these approaches may support the currently lacking decision-making and the fire suppression capacity, bringing the sustainability and the current forest policy into question [7]

Objectives

Methods

Discussion

Conclusion