Short Paper Soil charcoal stability over the Holocene across boreal northeastern North America Guillaume de Lafontaine a, b, ⁎, Hugo Asselin c a NSERC Northern Research Chair, Centre d'études nordiques, Département de Biologie, Université Laval, 1045 av. de la Médecine, Québec (QC), Canada G1V 0A6 b INRA, UMR BIOGECO 1202, 69 Route d'Arcachon, 33610, Cestas, France c NSERC/UQAT/UQAM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, 445, boulevard de l'Université, Rouyn-Noranda, Québec, Canada J9X 5E4 abstract article info Article history: Received 26 December 2010 Available online 31 July 2011 Keywords: Anthracomass Boreal Holocene Macroscopic soil charcoal Taphonomy The analysis of macroscopic wood charcoal fragments extracted from soils is frequently used as a palaeoecological tool for reconstructing stand-scale forest composition and fire history. Here we explored the putative loss of palaeoecological information due to charcoal degradation through time and in different biogeographical settings. We compared the relationship between charcoal mass and abundance for soil samples from five biogeographical regions of boreal northeastern North America spanning most of the Holocene period. We verified whether charcoal (Ø ≥ 2 mm) conservation differed as a consequence of different taphonomical processes between organic and mineral soil types. We also assessed the mass/ abundance relationship as a function of charcoal residence time in soil. Overall, the slope of the regression between charcoal particles mass (g) and abundance (number of particles) was 0.0042. The slope was not significantly different in samples from organic and mineral soil, and all biogeographical regions had similar slope values except one (higher charcoal fragmentation, probably due to high colluvial activity). Charcoal conservation also did not vary according to residence time in soil. This study shows that macroscopic soil charcoal particles resist fragmentation over millennia in different biogeographical settings and under the influence of various taphonomical processes. © 2011 University of Washington. Published by Elsevier Inc. All rights reserved. Introduction Botanical identification and direct radiocarbon AMS dating of macroscopic wood charcoal fragments extracted from soils are fre- quently used as palaeoecological tools in order to reconstruct stand- scale (i.e., in situ) past tree communities and fire history (e.g., Thinon, 1992; Gavin et al., 2003; Carnelli et al., 2004; Asselin and Payette, 2005; Talon et al., 2005; Sanborn et al., 2006; Vernet, 2006; Ali et al., 2008; Hart et al., 2008; Dutoit et al., 2009; Auger and Payette, 2010; Fesenmyer and Christensen, 2010; Henry et al., 2010; Poschlod and Baumann, 2010; Talon, 2010; Touflan et al., 2010; de Lafontaine and Payette, 2011, in press). Macroscopic soil charcoal analysis is useful to reconstruct local vegetation and wildfire history, especially in sites where other palaeoecological records are unavailable (Talon et al., 2005; de Lafontaine and Payette, 2011, in press). Although charcoal is chemically and biologically inert, deg- radation might occur by physical fragmentation of the particles during colluvial transportation, tree uprooting, or bio- or cryoturba- tion (Thinon, 1992; Weng, 2005; Théry-Parisot et al., 2010). This might result in decreased detection potential for older fire events, a major problem for palaeoecological reconstruction of fire history using soil charcoal. Furthermore, the processes involved in soil char- coal fragmentation might differ across sites (e.g., having contrasted soil types, climate, colluvial activity [slope] or species composition), making even more problematic the use of charcoal in palaeoecological studies. The present study explores the putative loss of palaeoecological information from charcoal degradation. We assessed whether char- coal breakage appeared to be a general problem in soil charcoal records from boreal sites. We explored the relationship between charcoal mass (anthracomass) and abundance (i.e., the number of charcoal particles [nchar]) extracted from soil samples from five different biogeographical regions of boreal eastern North America and spanning most of the Holocene. Using either anthracomass or nchar alone might be a sufficient measure of charcoal abundance. However, using the anthracomass/nchar relationship could prove more efficient to compare charcoal records across sites because it accounts for the importance of charcoal breakage in soils. On the one hand, the re- lationship between mass and number should generally be strong and positive. On the other hand, contrasted regression slopes (of the anthracomass/nchar relationship) across sites would indicate differ- ences in charcoal degradation processes (e.g., a low slope value in- dicating that more charcoal particles are necessary to reach a given anthracomass compared to a higher slope value, thus suggesting more charcoal fragmentation). An absence of significant differences Quaternary Research 76 (2011) 196–200 ⁎ Corresponding author at: INRA, UMR BIOGECO 1202, 69 Route d'Arcachon, 33610, Cestas, France. Fax: +33 5 57 12 28 81. E-mail addresses: gdelafon@pierroton.inra.fr (G. de Lafontaine), Hugo.Asselin@uqat.ca (H. Asselin). 0033-5894/$ – see front matter © 2011 University of Washington. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.yqres.2011.06.006 Contents lists available at ScienceDirect Quaternary Research journal homepage: www.elsevier.com/locate/yqres