1Polar Terrestrial Environmental Systems, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
2Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
3University of Chinese Academy of Sciences, Beijing, China
4Institute for Environmental Science and Geography, University of Potsdam, Potsdam, Germany
5Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
6Institute of Natural Sciences, North-Eastern Federal University of Yakutsk, Yakutsk, Russia
7Organic Geochemistry, German Research Centre for Geoscience (GFZ), Potsdam, Germany
1Polar Terrestrial Environmental Systems, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
2Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
3University of Chinese Academy of Sciences, Beijing, China
4Institute for Environmental Science and Geography, University of Potsdam, Potsdam, Germany
5Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
6Institute of Natural Sciences, North-Eastern Federal University of Yakutsk, Yakutsk, Russia
7Organic Geochemistry, German Research Centre for Geoscience (GFZ), Potsdam, Germany
Received: 24 May 2022 – Discussion started: 25 May 2022
Abstract. Wildfires play an essential role in the ecology of boreal forests. In eastern Siberia, fire activity has been increasing in recent years, challenging the livelihoods of local communities. Intensifying fire regimes also increase disturbance pressure on the boreal forests, which currently protect the permafrost beneath from accelerated degradation. However, long-term relationships between changes in fire regime and forest structure remain largely unknown. We assess past fire-vegetation feedbacks using sedimentary proxy records from Lake Satagay, Central Yakutia, Siberia, covering the past c. 10,800 years. Results from macroscopic and microscopic charcoal analyses indicate high amounts of burnt biomass during the Early Holocene, and that the present-day, low-severity surface fire regime has been in place since c. 4500 years before present. A pollen-based quantitative reconstruction of vegetation cover and a terrestrial plant record based on sedimentary ancient DNA metabarcoding suggest a pronounced shift in forest structure towards the Late Holocene. Whereas the Early Holocene was characterized by postglacial open larch-birch woodlands, forest structure changed towards the modern, mixed larch-dominated closed-canopy forest during the Mid-Holocene. We propose a potential relationship between open woodlands and high amounts of burnt biomass, as well as a mediating effect of dense larch forest on the climate-driven intensification of fire regimes. Considering the anticipated increase in forest disturbances (droughts, insect invasions, wildfires), higher tree mortality may force the modern state of the forest to shift towards an open woodland state comparable to the Early Holocene. Such a shift in forest structure may result in a positive feedback on currently intensifying wildfires. These new long-term data improve our understanding of millennial-scale fire regime changes and their relationships to changes of vegetation in Central Yakutia, where the local population is already being confronted with intensifying wildfire seasons.
Despite rapidly intensifying wildfire seasons in Siberian boreal forests, little is known about long-term relationships between changes in vegetation and shifts in wildfire activity. Using lake sediment proxies, we reconstruct such environmental changes over the past 10,800 years in Central Yakutia. We find that a more open forest may facilitate increased amounts of vegetation burning. The present-day dense larch forest might yet be mediating the current climate-driven wildfire intensification.
Despite rapidly intensifying wildfire seasons in Siberian boreal forests, little is known about...