Speaker
Description
Fires are an important factor in the shaping of ecosystems and are closely related with climate change, vegetation and, especially in more recent times, human action. Charred particles in sedi-ment cores are widely used as proxies for the reconstruction of fire histories, with the ultimate goal of revealing the local paleofire history of certain catchment. In this project we examined the a peat core from the Zenne Valley in Brussels that, according to radiocarbon dating, corresponds to the time span of Early to Late Holocene. Since data on the pollen content of the studied core were available as well, we carried out a comparison between fire history and the reconstructed vegeta-tion of the research site. The macroscopic charcoals from this sediment record were used to doc-ument the long-term local fire activity in the last ca. 10 000 years. The fire frequencies showed several pronounced peaks, situated around 8000 BP. The high consistency with increasing tempera-tures at this period indicates climate as a major driving factor, confirmed by the correspondence with other charcoal records from Northwest Europe. The results demonstrate the role of fuel build-up by pine and suggest fire-vegetation interactions associated with a pronounced fire event at 8000 BP. The Mid Holocene is characterized by a general decrease in fire frequency, but the sec-tion shows also peaks in fire activities around 7000, 6000 and 5100 BP. The time between two con-secutive fire events seems to remain constant, although the fire frequency gradually decreases between 7000-4200 BP from ca. 2 fires to 0 fires per 1000 years. Subsequently during the Late Holocene a rather quick increase in fire frequency is visible characterised by the occurrence of four fire evets per 1000 years from 3400 BP onwards and fire magnitude peaks, that can be seen at ca. 3400, 3200 and 2700 BP. The local paleofire signal of the Zenne valley is comparable to the paleofire trends from North-Western Europe indicating a link between biome types and fire activi-ty in the Early Holocene and asynchronous pattern in the Late Holocene.
