Topsoil microstructure changes after a shrubland prescribed burn (Central Pyrenees, NE Spain).

The dense thicket Echinospartum horridum (Vahl, Rothm) is expanded in secondary pastures of the Central Pyrenees (NE-Spain). The control of this grassland encroachment is attempted through prescribed burnings, trying to minimize its direct effects on the soil. But the structural changes on the new soil surface, burned and bare, are unknown in the medium-term.