Carbon emissions in Mediterranean shrubland wildfires: An experimental approach

Forest fire emissions modify the chemical composition of the atmosphere and the earth's climate system. The Ayoraburning experiment was designed to assess and quantify fire emissions from Mediterranean shrublands. A number of gaseous pollutants and particulate matter metrics (CO2, CO, CH4, PM2.5) were measured during 3 burning replicates by using real-time monitors. Quantification of carbon emissions released during the experiments showed that 71% was CO2, 26% CO, 3% CH4, and only 0.3% was particulate carbon. Emission factors obtained for CO2, CO and CH4 were 1257 ± 40, 453 ± 28 and 46 ± 12 g kg−1 dry matter, respectively, and combustion efficiencies ranged from 0.46 to 0.99. The experiments allowed the estimation of carbon emission in the different fire phases. Thus, 25% of carbon was sampled in the flaming phase and 75% of C in the smoldering phase.Current natural greenhouse gas (GHG) emission inventories in Mediterranean countries underestimate the actual emissions from forest fires since they do not consider forest shrub understory and shrublands and since they assume that the CO2 emitted is offset by forest re-growth.Our results may be used to improve current forest-fire emission inventories in southern Europe with special emphasis on shrublands.

► The experiments were performed to guarantee the conditions of a real fire.
► In situ monitoring measures have allowed estimating the percentage of carbon sampled.
► Low combustion efficiencies due to the structural composition of the shrubs.
► Experimental emission data will improve the information in emission inventories.