Effects of ground fires on element dynamics in mountainous coniferous forest in Germany

Disturbances such as fires are a natural phenomenon of forested ecosystems, having a different impact on (micro-) climate (e.g. emissions of gases and aerosols), ecology (destruction of flora and fauna) and nutrient cycles especially in the soils. Forest fires alter the spatial distribution (forest floor vs. mineral soil), binding forms (organic vs. inorganic) and availability (water solubility) of organic substances and nutrients. The effects of fires on chemical, biological and physical soil properties in forested ecosystems have been intensively studied in the last decades, especially in the Mediterranean area and North America. However, differences in fire intensity, forest type (species, age) and location (climate, geological substrate, nutrient status) lead to divergent results. Furthermore, only a few case studies focused on the effects of ground fires in hilly landscapes, on the vertical and lateral water-driven fluxes of elements (C, N, nutrients), as well as on the input of fire-released terrestrial nutrients into aquatic ecosystems. Thus, this study will evaluate the effects of low-severity fires on nutrient cycling in a coniferous forest in a hilly landscape connected to an aquatic system. At three spatially independent sites three paired plots (control and manipulated) were chosen at a forested site in Thuringia, Germany. All plots are similar in the vegetation cover and pedogenetic properties.In relation to control sites, this study will examine the effects of low-severity fires on:a) the mobilization of organic carbon and nutrients (released from ash material and the forest floor via leachate and erosion paths),b) the binding form (inorganic/organic) of elements and organic compounds, and c) the particle size fraction (DOM/POM) of elements and organic compounds.The goal of this study is a better understanding of the impact of forest fires on element cycling and release in a hilly landscape connected to an aquatic system, supposedly driven by climate changes.