Carob tree postfire: fire severity
One of the major factors generating dynamic in Euro-Mediterranean landscapes is rural abandonment and the consequent expansion of oldfields [1]. This oldfields are been colonized by fast-growing flammable plants, and this has occurred now for few decades [2]. Thus wildfires often spread through oldfields [2], and in fact the increasing of oldfields is the main driver of the increased fire activity in Spain since the 70’s [2]. One example of Mediterranean crop is the Carob tree [1]. Carob trees (Ceratonia siliqua; Fabaceae) are evergreen tree that produce edible pods, used in the past mainly as animal fodder; currently it is also used as substitute for chocolate (pods are sweet; in fact they can be eaten raw from the tree).
A recent wildfire in Azuébar (August 2021, eastern Spain) burned a landscape that had many abandoned Carob tree groves. These trees burned at a range of seventies (degree of consumption). So perhaps, by looking at the carob trees across the burned landscape we could map the severity of a wildfire! In the past we estimated fire severity using the degree of consumption of the pine canopy (Pinus halepensis) [3].
Pictures taken in September 2021, one month after the Azuébar fire.
References
[1] Pausas JG, Bonet A, Maestre FT, Climent A. 2006. The role of the perch effect on the nucleation process in Mediterranean semi-arid oldfields. Acta Oecol. 29: 346-352. [pdf] [doi] [ScienceDirect]
[2] Pausas JG & Fernández-Muñoz S. 2012. Fire regime changes in the Western Mediterranean Basin: from fuel-limited to drought-driven fire regime. Climatic Change 110: 215-226. [doi | springer | pdf]
[3] Pausas, J.G., Ouadah, N., Ferran, A., Gimeno, T. & Vallejo, R. 2003. Fire severity and seedling establishment in Pinus halepensis woodlands, eastern Iberian Peninsula. Plant Ecol. 169: 205-213 . [doi | pdf]