Carpathian Journal of Earth and Environmental Sciences

Fires are happened in the many forests locating in north of Iran, annually. Fires have changedsome chemical properties in soils during the combustion process. Hence, this study has focused on Effectof fire on soil nutrient availability. Soil samples were collected from three depths (0-3, 3-6 and 6-9 cm)under the forest floor one month after the fire in three forests (Pilimbra, Lakan and Saravan). These areasare covered by pine trees (pinus taeda). Results of this study indicated that the fire significantly increasedsand, pH, EC and BS while significantly decreased clay, organic carbon and CEC in comparison withunburned soil. Significant effect of fire limited to first and second depth and decreased with increasing ofdepth. Furthermore, the fire significantly increased soluble K, Ca, Mg, exchangeable K and available P. Effects of the fire on soil micronutrient was limited to available (DTPA extractable), iron and it had notsignificant effect on other micronutrient. Overall, fire effects on soil were directly related to the depth ofburn and the surface layer had most significant difference between burned and unburned soils. Higheravailability of nutrients in the soil during fire may be associated with the addition of ash.