NOAA/WDS Paleoclimatology - Héon and Arsensult fire data from northern boreal forest of eastern Canada

STUDY NOTES: Supporting Dataset S1 of the publication for this study: "Resistance of the boreal forest to high burn rates", submitted to PNAS is available with the publication and at: https://www.ncei.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/heon-arseneault-2014/supplemental/pnas2014-09316dataset-s1.xlsx) It contains fire dates estimated from tree ring analysis of fire scars and tree establishment dates collected in the fire-prone, unmanaged northern boreal forest of eastern Canada. The study has been designed so as to reconstruct the extent of wildfires that have overlapped over the last 200-300 years along a 190-km transect. The transect corresponds to the James Bay road in northern Québec and is subdivided into 93 cells of about 2 km2. Samples are trunk cross-section mostly taken on fire-scarred trees, or to a lesser degree, near the base of unscarred specimen. The full ingest of all FHX files for this study is in progress. All fire scar site FHX data, metadata along with all other IMPD North America fire scar files, are located in folder (URL): https://www.ncei.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/ Please visit the following file for an up to date list of metadata for all fire scar FHX data sites: https://www.ncei.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/mdata-heon-arseneault-2014.csv A description for each column of this file follows: A. site_name - name of the fire scar site B. impd_code - International Multi-proxy Paleofire Database(IMPD) code, assigned by NOAA C. Investigators - investigators D. first_year - earliest year contained in the FHX data file, AD units E. last_year - most recent year in the FHX file, AD units F. latitude - latitude in decimal degrees G. longitude - latitude in decimal degrees H. elevation - elevation in meters I. species - species codes; a full description of each species code is available from URL: https://www.ncei.noaa.gov/pub/data/paleo/templates/tree-species-code.csv J. number_of_trees - count of trees in the sites FHX data file K. reference_1 - top-ranked publication, any others are listed in the sites metadata file, listed in column Q, link_to_metadata L. dataset_doi - DOI for the data of the site M. contribution_year - year the site was contributed N. NOAA_study_id - study identifier, assigned by NOAA O. link_to_data - online resource for the FHX data file P. link_to_metadata - online resource for complete metadata for the site, in NOAA Template format. Note: this file contains the online resource links for all data and supplemental files including supplemental (tree) data, and fire history graphs depicting the FHX data. Q. link_to_landing_page - link to NOAA landing page for the site Author affiliations: Héon and Arseneault: Département de biologie, chimie et géographie, Centre d’Études Nordiques, Université du Québec à Rimouski, Rimouski (Québec), Canada, G5L 3A1. Parisien: Northern Forestry Centre, Canadian Forest Service, Natural Resources Canada, Edmonton, Alberta, Canada, T6H 3S5 Corresponding author: Dominique Arseneault Email: dominique_arseneault@uqar.ca Note: When using the data, please contact authors to avoid duplicating ongoing analyses. Dating Method: Crossdated
ABSTRACT SUPPLIED BY ORIGINATOR: Boreal ecosystems and their large carbon stocks are strongly shaped by extensive wildfires. Coupling of climate projections with records of area burned over the last 3 decades across the North American boreal zone suggests that area burned will increase by 30-500% by the end of the 21th century, with cascading impacts on ecosystem dynamics and on the boreal carbon balance. Fire size and the frequency of large-fire years are expected to increase. However, how fire size and time since previous fire will influence future burn rates is poorly understood, mostly due to incomplete records of past fire overlaps. Here, we reconstruct the length of overlapping fires along a 190-km long transect over the last 200 years in one of the most fire-prone boreal regions of North America in order to document how fire size and time since previous fire will influence future fire recurrence. We provide direct field evidence that extreme burn rates can be sustained by a few occasional droughts triggering immense fires. However, we also show that the most fire-prone areas of the North American boreal forest are resistant to high burn rates due to overabundant young forest stands, thereby creating a fuel-mediated negative feedback on fire activity. These findings will help refine projections of fire impacts on boreal ecosystems and their large carbon stocks.