Speaker
Description
Recent climate change in Siberia is increasing the probability of dangerous forest fires. The development of effective measures to mitigate and prevent fires is impossible without an understanding of long-term fire dynamics. We present the new multi-site palaeo-fire reconstruction based on macroscopic charcoal data from 16 peat and lake sediment cores located in different landscapes across the permafrost area of Central Siberia. The studied sites are situated in three model areas: the Putorana Plateau, the middle part of the Central Siberian Plateau (Lower Tungiska River basin, near the settlement of Tura) and the marginal part of West Siberian Lowlands (Yenisei River basin, near the town of Igarka). Charcoal records cover the last 7000 years. We used the Paleofire R package version 1.2.4 as the standardization technique of the obtained data to compare the local fire reconstructions from the study area. The composite cureve of biomass burning was compared with pollen and plant macrofossil data, reconstruction of total forest covarage by best modern analogue technique and July temperature reconstructions. The obtained results show similar temporal patterns of charcoal accumulation rates in the cores under study, and near synchronous changes in fire regimes. The paleo-fire record revealed moderate biomass burning between 7.0 and 5.9 and between 3.4 and 2.6 ka BP. The periods of lowest fire activity occurred in 5.9-4.2 and 2.6-1.5 ka BP, that coincided with regional climate cooling and moistening, and reduction of forest vegetation in the study regions. Charcoal accumulation rates increased to the mean values during the interval from 1.5 to 0.8 ka BP and appears to be partly synchronous with climate warming during the Medieval Climate Anomaly. Frequent fires may encourage local permafrost to thaw, creating better conditions for tree growth and regeneration, and likely favouring spruce expansion. Since 0.8 ka BP charcoal influx raised and exceed the main value until the present time. With exception of charcoal records from the Putorana Plateau the decrease of fire frequency during the Little Ice Age revealed from tree-ring data from Central Siberia was not recorded by the charcoal data from peat cores. Fire frequency and charcoal accumulation increased abruptly during the last 150 years, obviously due to human impact. Regional reconstructions of long-term fire history show that recent fires are unprecedented during the middle and late Holocene, with modern high biomass burning lying outside millennial and centennial variability of the last 7000 years.
