Effects of forest fire on short-term erosion and nutrient losses

Wild fires disturb thousands of hectares of forest area in the Mediterranean region every year. The aim of this study is to determine the amount of nutrient loss and erosion from the burned sites in the short term after the 2021 forest-fire in Aydıncık and Gülnar regions of Mersin. The study was carried out in stands of different ages located between 300 meters and 1100 m altitude. Ash and soil samples were taken after the fire. To estimate the biomass before the fire, unburned maquis areas were sampled adjacent the undisturbed areas. It was determined that there was approximately 28 tons ha-1 branch and leaf biomass and approximately 5 tons ha-1 forest floor organic matter in the bush area. After the fire, approximately 7 tons ha-1 of unburned shrub braches remained as standing dead wood in the site. The average ash thickness in all areas was determined as 1,7 ± 0,7 cm, without changing on a stand basis. The soil bulk density in the unburned control site was about 1.25 g cm-3. Compared to the control site, the post-fire soil bulk density decreased by approximately 35% in c, b, a and degraded red pine stands and by half in the maquis area. One month after the fire, the N density of the soil increased approximately 2.7 times in maquis, degraded and b-age red pine areas compared to the control areas. Based on erosion stake measurement the soil level, including the ash on top, has decreased by approximately 2 cm. One year after the fire, the N density in the first 20 cm soil depth is approximately 1/3 higher in maquis and degraded areas than in other stands.