New Paper: Using paleoecology to improve reference conditions for ecosystem-based management in western spruce-moss subdomain of Québec

I am very pleased to shared the first paper of Andy Hennebelle PhD dealing with management and paleoecology in the spruce forest of Québec: 

Hennebelle A., Grondin P., Aleman J. C., Ali A. A., Bergeron Y., Borcard D., & Blarquez O. 2018. Using paleoecology to improve reference conditions for ecosystem-based management in western spruce-moss subdomain of Québec. Forest Ecology and Management, 430, 157–165. https://doi.org/10.1016/j.foreco.2018.08.007 

Abstract:

Ecosystem based management in Québec is framed by reference conditions defining percentage of old-growth forest (> 100-years-old) and forest composition characterizing pre-industrial forest landscapes. In the western spruce-moss bioclimatic subdomain (154 184 km2) a fire cycle estimated at 150 years was used to target that 49% of the landscape has to be composed of old-growth forest. Yet, this target was developed using past (19th–20th C.) climate and vegetation data and assume that environment and ecosystem processes are homo- geneous for the entire western spruce-moss bioclimatic subdomain. The wide spatial and narrow temporal windows limit the application of reference conditions under ongoing climate change.

Our aim was to classify current vegetation heterogeneity of the western spruce-moss subdomain into homogeneous zones and to study the long-term history of fire and vegetation within these zones. This approach will help to refine forest management targets that are based upon short-term records by providing a long-term perspective that is needed for the forests to be managed within their natural range of variability. Modern forest inventories data were used along with climate, physical variables, and natural and human disturbances to study the current vegetation-environment interactions among the western spruce-moss subdomain. We also used 18 published sedimentary pollen and charcoal series to reconstruct Holocene vegetation and Fire Return Intervals (FRI).

Contemporary data revealed 4 zones with homogeneous interactions between vegetation and environment. Pollen analysis revealed three long-term vegetation paths: early successional species dominance, late to early species transition and late successional species dominance. These suggest that modern forest composition results from Holocene trajectories occurring within each zone. Holocene mean FRI (mFRI) ranged from 222 to 258 years across the subdomain, resulting in old-growth forests ranging between 64% and 68%, depending upon the zone.

Paleoecological and contemporary results support that to make forest management more sustainable, current landscape heterogeneity that arises from millennial forest composition trajectories and fire cycle dynamics should be taken into account by down-scaling the previously established reference conditions.

New Paper: The climate, the fuel and the land use: long-term regional variability of biomass burning in boreal forests

I am very happy to share this new paper about fire regime variability between Scandinavia and North America by Chiara Molinari and colleagues:

Molinari C., Lehsten V., Blarquez O., Carcaillet C., Davis B. A. S., Kaplan J. O., Clear J., Bradshaw R. H. W. 2018. The climate, the fuel and the land use: long-term regional variability of biomass burning in boreal forests. Global Change Biology, 1–18. https://doi.org/10.1111/gcb.14380 

Abstract

The influence of different drivers on changes in North American and European bor- eal forests biomass burning (BB) during the Holocene was investigated based on the following hypotheses: land use was important only in the southernmost regions, while elsewhere climate was the main driver modulated by changes in fuel type. BB was reconstructed by means of 88 sedimentary charcoal records divided into six dif- ferent site clusters. A statistical approach was used to explore the relative contribu- tion of (a) pollen‐based mean July/summer temperature and mean annual precipitation reconstructions, (b) an independent model‐based scenario of past land use (LU), and (c) pollen‐based reconstructions of plant functional types (PFTs) on BB. Our hypotheses were tested with: (a) a west‐east northern boreal sector with changing climatic conditions and a homogeneous vegetation, and (b) a north‐south European boreal sector characterized by gradual variation in both climate and vege- tation composition. The processes driving BB in boreal forests varied from one region to another during the Holocene. However, general trends in boreal biomass burning were primarily controlled by changes in climate (mean annual precipitation in Alaska, northern Quebec, and northern Fennoscandia, and mean July/summer temperature in central Canada and central Fennoscandia) and, secondarily, by fuel composition (BB positively correlated with the presence of boreal needleleaf ever- green trees in Alaska and in central and southern Fennoscandia). Land use played only a marginal role. A modification towards less flammable tree species (by promot- ing deciduous stands over fire‐prone conifers) could contribute to reduce circumbo- real wildfire risk in future warmer periods.

New paper: Guidelines for the use and interpretation of palaeofire reconstructions based on various archives and proxies

I am pleased to share this recent article by Cecile Remy and colleagues on the comparison of charcoal records using various archives:

Remy C. C., Fouquemberg C., Asselin H., Andrieux B., Magnan G., Brossier B., Grondin P., Bergeron Y., Talon B., Girardin M. P., Blarquez O., Bajolle L., Ali A. A. (2018). Guidelines for the use and interpretation of palaeofire reconstructions based on various archives and proxies. Quaternary Science Reviews, 193, 312-322.  https://doi.org/10.1016/j.quascirev.2018.06.010 

Abstract

We present a comparative analysis of fire reconstructions from tree rings and from wood charcoal preserved in forest soils, peat and lake sediments. Our objective is to highlight the benefits and limits of different archives and proxies to reconstruct fire histories. We propose guidelines to optimize proxy and archive choice in terms of spatial and temporal scales of interest. Comparisons were performed for two sites in the boreal forest of northeastern North America. Compared to others archives, tree-ring analysis remains the best choice to reconstruct recent fires (<1000 years). For longer periods (from several centuries to millennia), lake charcoal can be used to reconstruct regional or local fire histories depending on the method used, but the focus should be on historical trends rather than on the identification of individual fire events. Charcoal preserved in peat and soils can be used to identify individual fire, but sometimes cover shorter time periods than lake archives.

 

 

WORKSHOP REPORT: Applying paleofire records in ecological management

We are very glad to share the last report from the GPWG2 Montreal Workshop that is now published in Wildfire Magazine.

WORKSHOP REPORT: Applying paleofire records in ecological management, 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.

You can read the workshop report below or directly on Wildfire Magazine Here.

New paper: Late Holocene influence of societies on the fire regime in southern Québec temperate forests

I am really happy to share our last paper published in Quaternary Science Reviews with students and colleagues from the Department of Geography and Anthropology of UdeM:

Blarquez O., Talbot J., Paillard J., Lapointe-Elmrabti L., Pelletier N., Gates St-Pierre C. 2018. Late Holocene influence of societies on the fire regime in southern Québec temperate forests. Quaternary Science Reviews 180: 63–74. doi:10.1016/j.quascirev.2017.11.022  

Data will follow soon… 

Abstract: Climatic change that occurred during the Holocene is often recognized as the main factor for explaining fire dynamics, while the influence of human societies is less apparent. In eastern North America, human influence on fire regime before European settlement has been debated, mainly because of a paucity of sites and paleoecological techniques that can distinguish human influences unequivocally from climate. We applied a multiproxy analysis to a 12 000-year-old paleoecological sequence from a site in the vicinity of known settlement areas that were occupied over more than 7000 years. From this analysis, we were able detect the human influence on the fire regime before and after European colonization. Fire occurrence and fire return intervals (FRI) were based on analysis of sedimentary charcoals at a high temporal and spatial resolution. Fire occurrence was then compared to vegetation that was reconstructed from pollen analysis, from population densities deduced from archeological site dating, from demographic and technological models, and from climate reconstructed using general circulation models and ice-core isotopes. Holocene mean FRI was short (164 ± 134 years) and associated with small charcoal peaks that were likely indicative of surface fires affecting small areas. After 1500 BP, large vegetation changes and human demographic growth that was demonstrated through increased settlement evidence likely caused the observed FRI lengthening (301 ± 201 years), which occurred without significant changes in climate. Permanent settlement by Europeans in the area around 1800 AD was followed by a substantial demographic increase, leading to the establishment of Gatineau, Hull and Ottawa. This trend was accompanied by a shift in the charcoal record toward anthropogenic particles that were reflective of fossil fuel burning and an apparent absence of wood charcoal that would be indicative of complete fire suppression. An anthropogenic fire regime that was characterized by severe and large fires and long fire-return intervals occurred more than 1000 years ago, concomitant with the spread of native agriculture, which intensified with European colonization over the past two centuries.

Winter is coming

Notre dernière étude publiée dans New Phytologist fait la couverture du journal!

Le blog du journal nous fait également l’honneur d’un article par Mike Whitfield que vous trouverez ici: https://www.newphytologist.org/blog/behind-the-cover-new-phytologist-2164-december-2017/ 

Et repris ci dessous:

Winter has come to Lake Miroir. Below the surface, deep down in the dark, the lakebed sediments tell a story of ice and fire.

These days, snow covers the landscape from December to April, but this hasn’t always been the case. This lake contains sediments from the last glaciation, which ended about 15,000 years ago in the Alps. Interestingly these sediments contain proof of a glacial refugia of trees: cembra pines and larch. Trees survived the deep glacial winter here in isolation.

The snowy scene on the cover of New Phytologist 216:4 represents a site that contains proof of an extraordinary interplay between fire and vegetation in a periglacial environment. Christopher Carcaillet and Olivier Blarquez studied lake sediments nine metres below the surface. In their New Phytologistpaper, they describe how they discovered evidence of fire amid the ice. This refuge burned, with a very low frequency of about one fire per 1000 years. This is the first evidence of fire at such high altitude during glacial times, which were cold and dry.

Image: Lake Miroir, western Alps, France.
Lake Miroir, western Alps, France. Courtesy of Christopher Carcaillet.

Today, fire is about three times more frequent, with one fire every 300 years or so. The vegetation is naturally dominated by larch with cembra pines. While larch abound today, during glacial times the cembra pines were dominant. Carcaillet and Blarquez observed that when the vegetation switched from pine dominant to larch dominant, fires became more frequent. These results suggest that vegetation and fire interact, fire controlling the abundance of larch over cembra pine.

Christopher Carcaillet’s research focuses on determining the long-term relative influences of climate and social processes on the pattern of plant communities (e.g. biodiversity) or ecosystem dynamics through changes in disturbance regimes (such as fire, snow avalanche, or insect outbreak). Seeking similar evidence to that found at Lake Miroir, the researchers investigated a similar lake in the same region. While it also contains glacial sediments, it provides no evidence of trees nor of fire. This comparison shows that glacial climate does not prevent the occurrence of fires, but suggests that trees are needed to allow fires to ignite and spread.

Carcaillet and Blarquez’s research suggests that trees may have survived the long glacial winter in Europe in more places than previously thought. Despite finding refuge from the ice, however, they may not have been safe from fire.

Mike Whitfield
Development Coordinator
New Phytologist

Read the paper: Carcaillet, C. and Blarquez, O. (2017) Fire ecology of a tree glacial refugium on a nunatak with a view on Alpine glaciers. New Phytologist. doi: 10.1111/nph.14721

 

Our paper on African land-use change recommended in F1000Prime as being of special significance in its field!

Our paper “Land-use change outweighs projected effects of changing rainfall on tree cover in sub-Saharan Africa”  , has been recommended in F1000Prime as being of special significance in its field by F1000 Faculty Member George Malanson! Pr. Malanson summary:

Aleman et al. identified landscapes at risk in sub-Saharan Africa. A variety of data sources (satellite tree cover, climatic, soils, population density, and land use) are nicely combined in a statistical model (random forest) to identify the relative importance of variables. Future scenarios were developed and the random forest model re-used to predict future tree cover. Land use change was identified as a greater threat than climate change. Risk is assessed in terms of loss of tree cover and areas likely to be protected. Depending on scenario, projected loss of tree cover was high in both savanna and forest biomes, but tree cover increases could reduce the area of savanna. The highest risk is in an area south of the Sahel and with a connection to much of the Congo Basin. Given the role of land use, the conversion of savanna to biofuels to mitigate climate change is questioned. The paper could be used as an example for complementary analyses in other places. The focus on biome transitions (forest-savanna-grassland) in the context of land use highlights the importance of landscape level analyses. The action is at the edges.

New paper: Paleofire Dynamics in Central Spain During the Late Holocene: the Role of Climatic and Anthropogenic Forcing

I am very pleased to share this new article with José Antonio López-Sáez and colleagues: DOI:10.1002/ldr.2751 about the fire history of a mountain range in central Spain.  

Abstract:

The use of fire and, consequently, its severity and incidence on the environment, has grown steadily during the last millennia throughout the Mediterranean. This issue can be assessed in several mountain ranges of central Iberia where changes in the management policy on anthropic activities and exploitation of high-mountain environments have promoted a remarkable increase on fire frequency. Our research focuses on fire dynamics throughout the last three thousand years from three peat bog charcoal records of the Gredos range (central Iberia). Our aim is to reconstruct past fire regimes according to forest vegetation typology (Castanea sativa, Pinus pinaster, P. sylvestris). Charcoal influx shows low values between 3140 and 1800 cal. yr BP when forests were relatively dense both in high and mid-mountain areas. Fire appeared synchronous between 1800 and 1700 cal. yr BP for Lanzahíta and Serranillos and around 1400-1240 cal. yr BP for the three sites suggesting anthropogenic fire control between the Late Roman and the Visigothic periods that can be related to the cultivation of olive trees in the valleys and a greater human impact in high-mountain areas. By contrast, during the Muslim period (1240-850 cal. yr BP) fire dynamics becomes asynchronous. Later, fires turn again coeval in the Gredos range during the Christian period (850-500 cal. yr BP) and can be also correlated with drought phases during the Late Medieval Warm Episode. In short, our study demonstrates that fire activity has been enormously variable during the late Holocene in response to both short- and long-term regional and global climate, vegetation dynamics and land use changes.

New paper: Global Modern Charcoal Dataset (GMCD): A tool for exploring proxy-fire linkages and spatial patterns of biomass burning

I am very pleased to share this article by Donna Hawthorne, Colin J. Courtney Mustaphi, Julie Aleman et al. on a new tool and data repository the Global Modern Charcoal Dataset which is currently in development by the GPWG and colleagues working in paleofire research. The GMCD is a unique opportunity to develop paleofire research and achieve charcoal calibration in sediment which should bring new discussion opportunities amongst paleoecologist, modern ecologist, modellers and managers. Stay tuned for developments at http://www.gpwg.paleofire.orgLink to pdf

Abstract:  Progresses in reconstructing Earth’s history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjunction with changing climate, anthropogenic activities and land-use patterns, there is an increasing need to further understand, calibrate and interrogate recent and past fire regimes as related to changing fire emissions and changing carbon sources and sinks. Discussions at the PAGES Global Paleofire Working Group workshop 2015, including paleoecologists, numerical modelers, statisticians, paleoclimatologists, archeologists, and anthropologists, identified an urgent need for an open, standardized, quality-controlled and globally representative dataset of modern sedimentary charcoal and other sediment-based fire proxies. This dataset fits into a gap between metrics of biomass burning indicators, current fire regimes and land cover, and carbon emissions inventories. The dataset will enable the calibration of paleofire data with other modern datasets including: data of satellite derived fire occurrence, vegetation patterns and species diversity, land cover change, and a range of sources capturing biochemical cycling. Standardized protocols are presented for collecting and analyzing sediment-based fire proxies, including charcoal, levoglucosan, black carbon, and soot. The GMCD will provide a publically-accessible repository of modern fire sediment surface samples in all terrestrial ecosystems. Sample collection and contributions to the dataset will be solicited from lacustrine, peat, marine, glacial, or other sediments, from a wide variety of ecosystems and geographic locations.

Ref: 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. (no date) ‘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.