A workshop report by
- Kendrick J. Brown – Natural Resources Canada
- Mitchell J. Power – University of Utah
- Michal Słowiński – Polish Academy of Sciences
- Andri C. Van Aardt – University of the Free State
- Olivier Blarquez – Université de Montréal
- Pierre Grondin – Ministère de la Forêt, de la Faune et des Parcs
The Global Charcoal Database (GCD) is an open access database that stores paleofire data. It houses a range of sedimentary-based proxy records that chronicle wildfires of the past, spanning time intervals from decades to millennia and beyond. Examples of typical fire history records include those derived from fossil charcoal, black carbon, or fire-generated organic compounds such as levoglucosan and polycyclic aromatic hydrocarbons – produced during combustion of cellulose and lignin, respectively. The overarching goal of the GCD is to serve as a repository for paleofire data and to promote data sharing for research and education. In so doing, this shared database provides a mechanism for all researchers, at any stage of their career, to cooperatively engage with one another in cultivating enduring friendships and propelling scientific discovery.
The GCD is managed by the Global Paleofire Working Group (GPWG). For over a decade, the GPWG has received support from the organization Past Global Changes, often referred to as PAGES (http://www.pages-igbp.org/). Since its inception in 2006, the GCD has facilitated many peer-reviewed scientific investigations. The group’s inaugural paper, Changes in fire regimes since the Last Glacial Maximum: an assessment based on a global synthesis and analysis of charcoal data by Power et al. (2008), was published in the journal Climate Dynamics and now has over 400 citations. In addition to examining global trends of biomass burning through time, it also captures the spirit of the GCD, with over 80 contributing co-authors from various institutions around the world. Additional collaborations have produced more articles, all of which are available on the GCD website (http:// www.paleofire.org/welcome.php).
The GPWG holds annual workshops, bringing together a diverse community of scientists to review and initiate research projects, provide updates, address challenges and chart future directions. The most recent workshop was a three-day event in October 2017, at the Station Biologique des Laurentides, a University of Montreal field station near Montreal, Canada. The workshop brought together some 30 fire scientists from four continents, representing two dozen universities and government agencies, including the Government of Quebec and Natural Resources Canada.
The purpose of the workshop, titled Paleofire knowledge for current and future ecosystem management, was to explore the applicability of fire history data in ecosystem management. The workshop began with several presentations highlighting examples where management could and/or has benefited from paleoecological data, including establishing ecosystem reference conditions, characterizing modern forest condition, and aiding biodiversity conservation. An example of such application is management of spruce-moss forests in western Quebec, discussed in more detail below.
The primary objective of the workshop, linking paleofire data to management applications, required participants to break into sub-groups and summarize results of a pre-workshop questionnaire that surveyed a wide range of ecosystem managers, including forest practitioners and environmental conservationists. The questions posed identified data types, avenues of acquisition, and use in management, and answers included:
1. What are the main challenges when integrating scientific knowledge into effective management plans for you?
- “Human and financial resources. The lack of knowledge and limiting scientific data available, particularly baseline and long-term data.” (non-government agency)
- “Acceptance for reintroduction of past disturbance regimes. Capacity in performing management action.” (government agency)
- “Forestry is very conservative when it comes to adapting new knowledge.” (private company)
2. Do you believe that long-term knowledge of the fire regime in your area could be useful for defining ecosystem management strategies?
- “Yes, long-term knowledge of fire regimes could form a vital part in understanding the vegetation dynamics of a specific area and thus may have a role in formulating any management strategies.” (government agency)
- “Yes, long-term knowledge would give us even more certainty and confidence about the current developments based on contemporary fires.” (private company)
Other questions focused on longer-term perspectives, probing how paleofire data could aid ecosystem management. Each sub-group summarized the results from their questionnaires and presented the findings (Figure 1), culminating in a commitment to produce an article describing the results, complete with examples showing how paleoecology can aid forest management.
Focus areas for application of paleofire data include, for example:
and validating models,
The overarching objective of the paper is to provide managers, practitioners and conservationists with cutting-edge perspectives about fire in the environment. While the paper is still in preparation, it will be distributed to those who completed the original questionnaire and posted on the GCD website for wider readership.
One example illustrating the relevance of paleoecological data in management heralds from the spruce-moss forest of western Quebec, Canada. The provincial government aims to achieve 48% old growth forest, assuming a 150-year fire cycle (Boucher et al. 2011). However, inventory data reveal that this is not the case, with forest cover instead being relatively young, with little old growth forest — around 10% (Cyr et al. 2009). Consequently, there is a discrepancy between management targets and reality. Paleofire reconstructions show that the fire return interval ranged from 110-270 years over the last seven millennia. Using this information, it was possible to deduce that old growth forest was historically more abundant (50-70%), reinforcing the notion that age structure targets are appropriate and that a gap exists between historical, modern and target age class structure.
Other examples reveal surprising feedbacks among climate, fire and vegetation. Climate reconstructions show that a warm dry period occurred during the mid-Holocene interval throughout the northern hemisphere about 4000-8000 years ago, creating conditions favorable for burning. Yet various paleofire studies reveal a surprise — fire disturbance actually decreased in certain parts of the circumboreal, including Quebec (Girardin et al., 2013) and Fennoscandia (Brown and Giesecke, 2013). It is suggested that under past warm conditions, the expansion of broadleaf vegetation in the southern boreal forest offset the influence of climate and lowered fire risk by altering local microclimatic conditions as well as fuel type, arrangement, moisture content and flammability.
In another example from boreal Alaska, fire disturbance increased 5500 years ago under cool and moist climatic conditions (Lynch et al., 2003). In this case, it is believed that the expansion of highly flammable Picea marianna promoted fire, again revealing the importance of fire-climate-vegetation interactions. Looking forward, unanticipated feedbacks will undoubtedly influence future fire regimes. Paleofire reconstructions can help inform managers about such surprises.
In addition to exploring the relevance of paleofire research in the management of ecological systems, the workshop had several other parallel objectives, including launching the Global Modern Charcoal Database (GMCD). The GMCD represents an international collaboration tasked with collecting data that can be used to better calibrate charcoal records (Hawthorne et al. 2017). As part of this event, participants enjoyed an excursion to a nearby lake where the inaugural GMCD sample was collected by boat. The sample is comprised of lake surface sediment that contains, amongst other things, charcoal from recent fires. During a fire, charcoal can be transported from the burned area either atmospherically in plumes or by overland flow, with some eventually making its way into surrounding lakes where it is preserved in the sediment. Similar lake surface sediment samples will now be collected globally in order to build this new and exciting calibration dataset.
Student participants also attended the workshop. They committed to starting a paleofire blog, details of which will be posted on the GCD website. Finally, all workshop attendees also visited an oak woodland where soil pits were excavated to examine forest floor and mineral soil charcoal content.
The meeting concluded with an invitation to participate in the next workshop, which is being held in Egham, UK, from September 4-7, 2018 (http://www.pages-igbp.org/calendar/upcoming/127-pages/1756-gpwg2-meet-egham-18). The focus of the next meeting will build on these efforts to improve the synergies among fire policy practitioners and the biodiversity conservation community.
Boucher, Y., Bouchard, M., Grondin, P., Tardif, P. 2011. Le registre des états de référence : intégration des connaissances sur la structure, la composition et la dynamique des paysages forestiers naturels du Québec méridional. Direction de la recherche forestière. Ministère des Ressources naturelles et de la Faune. Mémoire de recherche forestière no 161. 21 p.
Brown, K.J., and Giesecke, T. 2014. Holocene fire disturbance in the boreal forest of central Sweden. Boreas, 43: 639–651. doi:10.1111/bor.12056.
Cyr, D., Gauthier, S., Bergeron, Y., Carcaillet, C. 2009. Forest management is driving the Eastern North American boreal forest outside its natural range of variability. Frontiers Ecol. and Environ., 7:519‑524.
Girardin, M.P., Ali, A.A., Carcaillet, C., Blarquez, O., Hely, C., Terrier, A., Genries, A., and Bergeron, Y. 2013. Vegetation limits the impact of a warm climate on boreal wildfires. New Phytol., 199: 1001–1011. doi:10.1111/nph.12322. PMID:23691916.
Hawthorne, D., Courtney Mustaphi, C. J., Aleman, J. C., Blarquez, O., Colombaroli, D., Daniau, A.-L., Marlon, J. R., Power, M., Vannière, B., Han, Y., Hantson, S., Kehrwald, N., Magi, B., Yue, X., Carcaillet, C., Marchant, R., Ogunkoya, A., Githumbi, E. N. and Muriuki, R. M. 2017. Global Modern Charcoal Dataset (GMCD): A tool for exploring proxy-fire linkages and spatial patterns of biomass burning. Quaternary International. doi: http://doi.org/10.1016/j.quaint.2017.03.046.
Lynch, J.A., Clark, J.S., Bigelow, N.H., Edwards, M.E., and Finney, B.P. 2003. Geographic and temporal variations in fire history in boreal ecosystems of Alaska. J. Geophys. Res., 107: 8152. doi:10.1029/2001JD000332.