Post-fire soil microbial biomass and nutrient content of a pine forest soil from a dunal Mediterranean environment

A chronosequence of forest fires (from 1981 to 1992) in a homogeneous Mediterranean pine forest ecosystem was investigated. The effect of fire on soil microbial biomass was evaluated in the 0–5 cm soil layer utilizing the substrate induced respiration (SIR) method (Anderson and Domsch, 1978) and the fumigation extraction (FE) method (Sparling and West, 1988). The C, N and P contents of soil surface layer were greater 1 y after a fire and declined in soils as time since the last fire increased. After 11 y, the soil nutrient content and the size of the microbial biomass were still lower than the neighbouring unburned site suggesting that forest fires have a long-term effect on soil microbiological properties.