Summary
Published in Forest Ecology and Management, 433: 376-385.
Analysis and ¹⁴C dating of charcoal fragments ≥ 2 mm buried in mineral soils make it possible to obtain a stand-scale portrait of Holocene fires that occurred in well-drained, fire-prone environments, as well as changes in forest stand composition over time, based on botanical identification of charcoals. Yet, it is not always possible to reconstruct all fire events, due to disturbances that have altered soil stratigraphy. To evaluate the efficacy of this approach, we conducted a comparative analysis with a proximal environment that presents an a priori continuous stratigraphy of charcoal fragments. For two sites in the coniferous boreal forest of eastern North America, the charcoal record of a forest soil was compared with that of an adjacent peatland margin situated at a distance of 20 m. For both types of sedimentary environments, a similar fire history was reconstructed for a most of the Holocene. The greatest differences were for the early Holocene period, for which a smaller number of fires were detected in the forest soil compared to the peatland soil. Retracing the oldest fires using mineral soils in a fire-prone environment is more difficult, given charcoal decay that results from repeated fire events. Yet, forest soils reveal a relatively accurate fire history for subsequent millennia if the number of charcoals being dated is sufficiently large. Any accurate reconstruction of the fire history of proximal peatland environments is strongly dependent on continuous stratigraphic units of peat and charcoal. Indeed, the age of charcoal fragments in peat may be different from that of the sedimentary layer in which they are buried due to allogenic disturbances such as erosion events caused by deep burning of the organic horizon and other mass-wasting events. Despite the large number of ¹⁴C dates it requires, analysis of soil macro-charcoal yields a realistic picture of the fire history at the stand scale. The concurrent analysis of macro-charcoal from adjacent peatland deposits may be used as a complement to more accurately record the oldest fire events.
File
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forest Ecology, Forestry Research, Inventory
Departmental author(s):
Author(s)
COUILLARD, Pierre-Luc, Joanie TREMBLAY, Martin LAVOIE and Serge PAYETTE
Year of publication :
2019
ISSN
0378-1127
Keywords :
Holocene epoch, boreal forests, burning, carbon, charcoal, fire history, fires, forest soils, forest stands, mass movement, mineral soils, organic horizons, peat, peatlands, radiocarbon dating, stand composition, stratigraphy, North America
