Water-stable aggregates in a burned soil at different intensities eighteen years after a forest fire

In 2012, eighteen years after aforest fire that took place in 1994 and burned a Pinus pinaster plantation, the soil aggregate stability is analysed and compared with aggregates of an unburned control area. The burned area was divided into three zones just after the fire, low, medium and high intensity fire, depending on the intensity at which burned each of the three zones. The results of the sampling in 2012, were compared to the analysis of the soil aggregates in 1994 and 1995. The results show that after eighteen years the aggregates of the burned zones are less stable based on two analytical methods, and the differences between burned areas are not significant. The fact that the soil of the control zone has more organic matter and concentration of chemical elements like, calcium, magnesium and iron, seems to be the determining factor of greater stability of surface aggregates in the control zone.