8 results on '"Frégeau, Mathieu"'
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2. Post-Glacial Climate–Fire Interactions Control Tree Composition of Mesic Temperate Forests in Eastern North America.
- Author
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Payette, Serge, Pilon, Vanessa, Frégeau, Mathieu, Couillard, Pierre-Luc, and Laflamme, Jason
- Subjects
TEMPERATE forests ,DECIDUOUS forests ,WHITE pine ,SUGAR maple ,FOREST succession - Abstract
Stand-scale gap-phase dynamics is generally viewed as the main driver of development in mesic deciduous forests of the temperate biome. Soil charcoal of temperate forests in eastern North America are unnoticed in most surveys, thus explaining why fire is undervalued as a driver of forest succession. The extent to which gap-phase, fire, or other processes are responsible for the regeneration and maintenance of mesic deciduous forests is unknown because paleoecological evidence is lacking. We tested the fire-driven succession hypothesis on the development of this major forest type. Based on charcoal
14 C dates of two sites, 44 and 55 fires occurred since early Holocene, with a mean interval of 170 to 215 years. The vegetation of both sites followed comparable post-glacial trajectories consisting of three distinct periods. Conifers dominated the two first periods during 5200–6000 years and were replaced by hardwoods–conifers over the last 3500 years. The first period was represented by boreal conifers, whereas the second period, dominated by white pine (Pinus strobus) forests, persisted during 3000–4300 years. The third period marked the development of hardwood (sugar maple, Acer saccharum) forests. Fires occurred continuously on the sites since early Holocene likely under dry conditions during the conifer periods and cooler and moister conditions during the hardwood–conifer period. Recurrent fires appear with climate as key drivers of the long-term dynamics of several temperate forests in eastern North America. Similar studies on other temperate forests should be pursued to test the hypothesis of climate–fire interactions influencing tree composition change. [ABSTRACT FROM AUTHOR]- Published
- 2021
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3. Macrocharcoal-Based Chronosequences Reveal Shifting Dominance of Conifer Boreal Forests Under Changing Fire Regime.
- Author
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Couillard, Pierre-Luc, Payette, Serge, Lavoie, Martin, and Frégeau, Mathieu
- Subjects
BLACK spruce ,FOREST management ,BALSAM fir ,PLANT species ,FOREST ecology - Abstract
Balsam fir (Abies balsamea) and black spruce (Picea mariana) forests are the main conifer forest types in the North American boreal zone. The coexistence of the two species as well as their respective canopy dominance in distinct stands raises questions about the long-term evolution from one forest type to the other in relation to environmental factors including climate and stand disturbance. We tested the hypothesis that repetitive fire events promote the succession of balsam fir forest to black spruce forest and vice versa. Postfire chronosequences of one black spruce (BSP) and one balsam fir (BFI) sites were reconstructed based on the botanical composition and
14 C-dated soil macrocharcoals. The results support the hypothesis of a successional dynamics. The BSP site has been affected by fires for the last 7600 years, whereas the BFI site, after having been impacted by several fires during the first half of the Holocene, evolved in a fire-free environment for the last 4400 years. Periods of fire activity facilitated the dominance of black spruce forests. The cessation of fires around 4400 cal. years BP on BFI site marks the beginning of the transition from black spruce to balsam fir stands. This succession is a long process, due to the ability of black spruce to regenerate by layering in the absence of fire. The resulting balsam fir stands are ancient and precarious ecosystems, since fire generally leads to the return of black spruce. The increase in balsam fir to the detriment of black spruce in boreal forests is a response to a decrease in fire frequency. [ABSTRACT FROM AUTHOR]- Published
- 2018
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- View/download PDF
4. Sugar maple ( Acer saccharum) at its northeastern range limit: a fire-resilient tree species.
- Author
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Payette, Serge, Frégeau, Mathieu, Couillard, Pierre-Luc, Pilon, Vanessa, and Laflamme, Jason
- Subjects
SUGAR maple ,FOREST management ,BIODIVERSITY ,HABITATS ,PLANT species - Abstract
Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
5. Long-term fire history of maple ( Acer) forest sites in the central St. Lawrence Lowland, Quebec.
- Author
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Payette, Serge, Pilon, Vanessa, Couillard, Pierre-Luc, and Frégeau, Mathieu
- Subjects
MAPLE ,FOREST fire ecology ,CHARCOAL ,DECIDUOUS plants - Abstract
Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2016
- Full Text
- View/download PDF
6. Fire history of the central boreal forest in eastern North America reveals stability since the mid-Holocene.
- Author
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Frégeau, Mathieu, Payette, Serge, and Grondin, Pierre
- Subjects
HOLOCENE Epoch ,TAIGAS ,PALEOECOLOGY ,CLIMATE change ,PLANT communities - Abstract
Past and present fire frequencies are key factors to evaluate fire-mediated changes in climate, but this metric is difficult to evaluate realistically in paleoecological and climatic reconstructions. Here, we applied charcoal analysis of forest soils to test from direct evidence the stability and resilience of the eastern North-American boreal forest at the Holocene timescale. Current knowledge indicates that the boreal forest is not so stable and resilient in several parts of its range, particularly at its northern and southern edges where it is converted to tundra and woodland communities, respectively. However, it is not known to what degree the structure and composition of the boreal forest situated at the central core of its range (FCR), far from the climate-sensitive edges, have been modified during the Holocene. To address the long-term status of the boreal forest vis-a-vis the Holocene climate, we have used a large dataset composed of
14 C-dated and botanically identified charcoal. Long-term fire frequencies in several sites of the FCR were calculated to assess the stability of the main forest ecosystems. The mean fire interval over the last 5000 years of the two principal ecosystems composed of black spruce–jack pine forests and black spruce–balsam fir forests was ~200 and >300 years, respectively. Fires occurred repetitively during this period without fire gaps longer than 400 years (ecosystem 1) and 600 years (ecosystem 2), an indication that the fire regime of the FCR remained stable since the mid-Holocene. Unchanged forest ecosystems during this period also suggest the maintenance of both fire-prone and less fire-prone tree species in their respective sites and the ability of the boreal biome to maintain its structure and function in a repetitive fire-disturbance regime. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
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7. Holocene dynamics of an eastern hemlock (Tsuga canadensis) forest site at the northern range of the species limit.
- Author
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Payette, Serge, Pilon, Vanessa, Couillard, Pierre-Luc, and Frégeau, Mathieu
- Subjects
EASTERN hemlock ,CONIFERS ,HARDWOOD forests ,HOLOCENE paleoclimatology ,COARSE woody debris - Abstract
Eastern hemlock (Tsuga canadensis) is a shade-tolerant tree of the temperate conifer-hardwood forests of northeastern North America whose northern limit of distribution coincides with the St Lawrence River around Québec City (Canada). We have analyzed the structure and dynamics of one of the very few old-growth hemlock stands in this area to evaluate its successional status at the Holocene scale. To document the origin and long-term development of the hemlock site, we have used conventional forest surveys and macrofossil analysis of woody debris and charcoal pieces at the soil surface and buried in the mineral soil. The ‘Rivière-du-Moulin hemlock forest’ is an old-growth forest, at least 1000 years old, whose structure has been rejuvenated by recurrent surface fires killing most plants of the shaded forest floor and facilitating hemlock regeneration. According to the number of fires and the corresponding fire intervals, the hemlock site experienced a sustained fire regime since the mid-Holocene, first in a developmental context of hardwood forests where beech (Fagus), butternut (Juglans), and birch (Betula) were growing, and then for the last 2400–2100 years as conifer forests where hemlock prevailed throughout or during a large part of the period. Our data highlight the influence of fire on the dynamics of hemlock-hardwood stands, a forest ecosystem generally viewed as being controlled by local light and medium canopy-gap disturbances. Soil charcoal analysis of conifer-hardwood forests may be used concurrently with canopy-gap analysis to decipher the influence of stand-scale disturbances and to calculate better forest turnover at several time scales. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
8. The velocity of postglacial migration of fire-adapted boreal tree species in eastern North America.
- Author
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Payette S, Couillard PL, Frégeau M, Laflamme J, and Lavoie M
- Subjects
- Canada, Ice, Fires, Picea, Pinus
- Abstract
The Earth's climate has been warming rapidly since the beginning of the industrial era, forcing terrestrial organisms to adapt. Migration constitutes one of the most effective processes for surviving and thriving, although the speed at which tree species migrate as a function of climate change is unknown. One way to predict latitudinal movement of trees under the climate of the twenty-first century is to examine past migration since the Last Glacial Maximum. In this study, radiocarbon-dated macrofossils were used to calculate the velocity of past migration of jack pine ( Pinus banksiana ) and black spruce ( Picea mariana ), two important fire-adapted conifers of the North American boreal forest. Jack pine migrated at a mean rate of 19 km per century (km
-cent ) from unglaciated sites in the central and southeastern United States to the northern limit of the species in subarctic Canada. However, the velocity increased between unglaciated and early deglaciated sites in southern Quebec and slowed from early to mid-Holocene in central and eastern Quebec. Migration was at its lowest speed in late-Holocene times, when it stopped about 3,000 y ago. Compared with jack pine, black spruce migrated at a faster mean rate of 25 km-cent from the ice border at the last interstadial (Bølling/Allerød) to the species tree limit. The modern range of both species was nearly occupied about 6,000 y ago. The factors modulating the changing velocity of jack pine migration were closely associated with the warm-dry climate of the late Pleistocene-Holocene transition and the more humid climate of the mid- and late-Holocene.- Published
- 2022
- Full Text
- View/download PDF
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