Temporary changes of the edaphic characteristics during the first year of postfire regeneration in two oak groves

Changes in chemical composition of surface 5 cm soil were examined during I year following a fire in two Quercus pyrenaica ecosystems. The soils were analyzed for available Ca, Mg, P, K, total N, organic C, and pH. The principal component analysis, including the magnitudes and rates of increases or decreases of the chemical components, showed that the postfire soils of the two ecosystems had a markedly different behavior. The reasons for the differences were ascribed primarily to the intensity of the fire, caused by different understory vegetation and climatic situations.