[automatically translated] For several years, the fires in the Mediterranean tend to increase in number and area concerned. To date, in Italy, the land area affected by fire is approximately 100,000 hectares year-1, half of which is woodland. Nationally, Sicily is among the regions marred by forest fires. The fire effects can be basically divided into two types: a) direct, through combustion, whose impact is proportional to the duration and course of the fire and b) indirect, mediated by the induced heating of the soil and that has an impact on 'entity and on the speed of the processes that take place in it. Combustion is a chemical-physical process of rapid decomposition, which occurs only in the presence of fuel (plant material), dell ' oxygen and a small amount of high-potential heat (trigger), which determines the development in the chain of the process itself. The physico-chemical properties of the soil undergo changes at temperatures higher than 200 ° C, while the biological component is also alters at lower temperatures. Temperatures exceeding 50 ° C can cause the death of soil microorganisms, with the thermo-labile bacteria fungi. The objective of this work was to evaluate, in the laboratory, the effects of heating for 30 minutes at 160 or 380 ° C (respectively low and medium intensity fire), and the subsequent moistening with fresh or salt water, the stability of biomass microbial a forest soil under different species (Eucalyptus camaldulensis, E. occidentalis, Cupressus sempervirens, Pinus halepensis). The three experimental factors investigated (woody species, type of heating and water for moistening) all have significantly affected the soil microbial biomass, as well as its composition. The heating to 380 ° C has been the factor that has caused a greater reduction of the microbial biomass of the soil pool. The bacteria, compared to fungi and mycorrhizae, showed greater resistance to the heating of the soil, in particular at the highest temperature (380 ° C). The type of water used for moistening after heating plays a key role in influencing, at the same temperature, the diversity and species evenness of the microbial community. In addition, the soil microbial community showed a different stability to experimental factors depending on the different essences, confirming that the forest cover plays a key role in the development and evolution of the soil microflora. The microbial communities that are less resistant to investigated experimental factors seems that has been established under Pinus halepensis.
|Number of pages||1|
|Publication status||Published - 2011|