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Forest fires are one of the factors that play an important role in both global warming and nutrient accumulation in soils. The level of these effects varies according to the severity and intensity of the fire. This study was conducted to determine the one-year effects of fire on soil properties and nitrogen mineralization in Turkish Pine stands exposed to low-intensity surface fire that naturally occurred at the Sarıçiçek region the Vezirköprü district of Samsun province in 2014, in Turkey. To this end, six sampling areas were selected from both burned and unburned (control) areas in the sections. Soil samples were taken from a depth of 0-5 cm and 5-10 cm. Nitrogen mineralization was determined by the land incubation in 3 periods (April-July-October, 2014) on-site holding method. Among soil properties, texture, pH, organic matter, total nitrogen, bulk density and carbon (C) / nitrogen (N) ratio analyses were assessed. As a conclusion, it was observed that significant differences occurred in soil properties and nitrogen mineralization temporarily. Average nitrogen mineralization at a depth of 0-10 cm over the one-year period was found to be 23.56 kg /ha in the burned areas and 25.2 kg/ha in the control areas. As a result of the study, it was concluded that the fire was more effective, especially at a depth of 0-5 cm in regards to changing the soil properties. Nitrogen mineralization at a depth of 0-5 cm was greater in the burned areas compared to controls. It was determined that especially low-intensity fires were not effective toward the lower depth levels.

Graphical abstract, Surface fuels are the critical link between structure and function in frequently burned pine ecosystems, which are found globally (Williamson and Black, 1981; Rebertus et al., 1989; Glitzenstein et al., 1995) [[1], [2], [3]]. We bring fuels to the forefront of fire ecology through the concept of the Ecology of Fuels (Hiers et al. 2009) [4]. This concept describes a cyclic process between fuels, fire behavior, and fire effects, which ultimately affect future fuel distribution (Mitchell et al. 2009) [5]. Low-intensity surface fires are driven by the variability in fine-scale (sub-m level) fuels (Loudermilk et al. 2012) [6]. Traditional fuel measurement approaches do not capture this variability because they are over-generalized, and do not consider the fine-scale architecture of interwoven fuel types. Here, we introduce a new approach, the “3D fuels sampling protocol” that measures fuel biomass at the scale and dimensions useful for characterizing heterogeneous fuels found in low-intensity surface fire regimes. • Traditional fuel measurements are oversimplified, prone to sampling bias, and unrealistic for relating to fire behavior (Van Wagner, 1968; Hardy et al., 2008) [7,8]. • We developed a novel field sampling approach to measuring 3D fuels using an adjustable rectangular prism sampling frame. This voxel sampling protocol records fuel biomass, occupied volume, and fuel types at multiple scales. • This method is scalable and versatile across ecosystems, and reduces sampling bias by eliminating the need for ocular estimations.

After wildfire, surviving trees are of major ecological importance as they can help in the post-fire regeneration process. Although these trees may be damaged, they may also benefit from reduced fuel hazard and competition. However, little is known about the long-term growth response of surviving trees. This study aims to explain short- to long-term variations in the postfire growth of surviving black pines in an area burnt in 1994, focusing on levels of fire severity and tree sizes. Relative basal area increments were used to detect time-course variations in postfire radial tree growth depending on fire severity. Linear mixed-effects models were used to describe the factors affecting postfire ring growth. In the short term, fire caused stronger reduction in growth in small trees with increasing bole char height. However, as time since fire increased, a positive effect of fire on growth due to reduced competition counteracted the short-term fire impacts. Indeed, small surviving trees demonstrated a surge in growth 15 years after the fire. It was concluded that reduced competition might offset the short-term negative effects of fire in surviving black pines.