The fire, burned areas and charcoal - charcoal-data modelling of burned areas, cross-validation of the fires and charcoal signal

Abstract

Fire is one of the fundamental factors that governs and shapes the functioning of many ecosystems and directly influences changes in vegetation, biodiversity and ancient societies. Recent decades have shown how wildfires and their associated global relationships contribute to accelerate climate change through changes in vegetation, permafrost conditions, and the release of residues, greenhouse gases and aerosols. The last IPCC report shows that the European region is characterized by an increase in fires directly caused by current climate change. In addition, forecasts for the next century indicate a continuous increase in air temperature, which could lead to an increase in the frequency and intensity of wildfire events. In this regard, the questions arise: What are the social and environmental impacts of future unexpected climate events? And how could an increase in wildfires accelerate climate change? During a fire, smoke, particles and various chemical compounds are released into the atmosphere, which can have a harmful effect on human health. Because of these consequences, it is important to understand what affects the occurrence and severity of fires. Paleofire reconstructions are useful for studying the effects of climate change and vegetation on fires at a time when human influence was less than today. Archived charcoal particles  in peat and lake sediments have been successfully used as geographic patterns in changing fire conditions. However, as many publications show, charcoal data can only provide partial estimates of changes in biomass burning. Therefore, the aim of the project is to indicate and verify the relationship between fire and its record in peat and lake sediments. To do this, burned areas within 40 km of 10 test sites (lakes and peatlands) are identified, and the intensity of each fire is estimated using fire data (i.e. fire type: ground, surface or crown), fire indicators (burnt area, weather conditions, wind speed and direction), fuel information (ecosystem type, forest age and species structure), obtained from the State Forests. Past fires and regional vegetation will be reconstructed using cores collected from lakes and peatlands based on pollen and charcoal analysis  with morphotypes in six fractions (100, 150, 200, 300, 400, 500 μm) with a high sampling resolution (0.5-1 cm). μ-XRF scanning will also be utilised to detect erosion and redeposition processes. The chronology will based on radiocarbon dating (AMS) and cesium-137 dating. Finally, the model of the spread of charcoal from the burnt area will be created. We assume that the amount of carbon accumulated on the lake and marsh surface is directly proportional to fire distance, burned area, and fire intensity. In this project, we want to advance the interpretation of reconstructed fires. This study could be the next step to better understand the fire signals preserved in our archives and improve the interpretation of paleo fires. This research is funded by the Polish National Science (No. 2023/49/N/ST10/04035).