Reduced Postfire Tree Regeneration Along A Boreal Forest-Forest-Tundra Transect in Northern Quebec

Ecology ◽  
1991 ◽  
Vol 72 (2) ◽  
pp. 619-627 ◽  
Author(s):  
Luc Sirois ◽  
Serge Payette
Keyword(s):  
Boreal Forest ◽  
Tree Regeneration ◽  
Forest Tundra

scholarly journals Spatially explicit fire-climate history of the boreal forest-tundra (Eastern Canada) over the last 2000 years

2007 ◽  
Vol 363 (1501) ◽  
pp. 2299-2314 ◽  
Author(s):  
Serge Payette ◽  
Louise Filion ◽  
Ann Delwaide
Keyword(s):  
Boreal Forest ◽  
Fire History ◽  
Forest Cover ◽  
Tree Regeneration ◽  
Spatially Explicit ◽  
Fire Event ◽  
Climate History ◽  
Forest Tundra ◽  
Disturbance Factor ◽  
History Of

Across the boreal forest, fire is the main disturbance factor and driver of ecosystem changes. In this study, we reconstructed a long-term, spatially explicit fire history of a forest-tundra region in northeastern Canada. We hypothesized that current occupation of similar topographic and edaphic sites by tundra and forest was the consequence of cumulative regression with time of forest cover due to compounding fire and climate disturbances. All fires were mapped and dated per 100 year intervals over the last 2000 years using several fire dating techniques. Past fire occurrences and post-fire regeneration at the northern forest limit indicate 70% reduction of forest cover since 1800 yr BP and nearly complete cessation of forest regeneration since 900 yr BP. Regression of forest cover was particularly important between 1500s–1700s and possibly since 900 yr BP. Although fire frequency was very low over the last 100 years, each fire event was followed by drastic removal of spruce cover. Contrary to widespread belief of northward boreal forest expansion due to recent warming, lack of post-fire recovery during the last centuries, in comparison with active tree regeneration more than 1000 years ago, indicates that the current climate does not favour such expansion.

scholarly journals Effects of Soil Abiotic and Biotic Factors on Tree Seedling Regeneration Following a Boreal Forest Wildfire

Ecosystems ◽  
2021 ◽  
Author(s):  
Theresa S. Ibáñez ◽  
David A. Wardle ◽  
Michael J. Gundale ◽  
Marie-Charlotte Nilsson
Keyword(s):  
Boreal Forest ◽  
Betula Pendula ◽  
Fire Severity ◽  
Tree Regeneration ◽  
Soil Biota ◽  
Fire Disturbance ◽  
Burn Severity ◽  
Soil Conditions ◽  
Tree Seedling ◽  
Seedling Regeneration

AbstractWildfire disturbance is important for tree regeneration in boreal ecosystems. A considerable amount of literature has been published on how wildfires affect boreal forest regeneration. However, we lack understanding about how soil-mediated effects of fire disturbance on seedlings occur via soil abiotic properties versus soil biota. We collected soil from stands with three different severities of burning (high, low and unburned) and conducted two greenhouse experiments to explore how seedlings of tree species (Betula pendula, Pinus sylvestris and Picea abies) performed in live soils and in sterilized soil inoculated by live soil from each of the three burning severities. Seedlings grown in live soil grew best in unburned soil. When sterilized soils were reinoculated with live soil, seedlings of P. abies and P. sylvestris grew better in soil from low burn severity stands than soil from either high severity or unburned stands, demonstrating that fire disturbance may favor post-fire regeneration of conifers in part due to the presence of soil biota that persists when fire severity is low or recovers quickly post-fire. Betula pendula did not respond to soil biota and was instead driven by changes in abiotic soil properties following fire. Our study provides strong evidence that high fire severity creates soil conditions that are adverse for seedling regeneration, but that low burn severity promotes soil biota that stimulates growth and potential regeneration of conifers. It also shows that species-specific responses to abiotic and biotic soil characteristics are altered by variation in fire severity. This has important implications for tree regeneration because it points to the role of plant–soil–microbial feedbacks in promoting successful establishment, and potentially successional trajectories and species dominance in boreal forests in the future as fire regimes become increasingly severe through climate change.

scholarly journals Caribou Conservation: Restoring Trees on Seismic Lines in Alberta, Canada

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 185 ◽  
Author(s):  
Angelo Filicetti ◽  
Michael Cody ◽  
Scott Nielsen
Keyword(s):  
Boreal Forest ◽  
Rangifer Tarandus ◽  
Site Preparation ◽  
Tree Regeneration ◽  
Tree Density ◽  
Petroleum Exploration ◽  
Rangifer Tarandus Caribou ◽  
Mechanical Site Preparation ◽  
Undisturbed Forest ◽  
Seismic Lines

Seismic lines are narrow linear (~3–8 m wide) forest clearings that are used for petroleum exploration in Alberta’s boreal forest. Many seismic lines have experienced poor tree regeneration since initial disturbance, with most failures occurring in treed peatlands that are used by the threatened woodland caribou (Rangifer tarandus caribou). Extensive networks of seismic lines, which often reach densities of 40 km/km2, are thought to have contributed to declines in caribou. The reforestation of seismic lines is therefore a focus of conservation. Methods to reforest seismic lines are expensive (averaging $12,500 per km) with uncertainty of which seismic lines need which treatments, if any, resulting in inefficiencies in restoration actions. Here, we monitored the effectiveness of treatments on seismic lines as compared to untreated seismic lines and adjacent undisturbed reference stands for treed peatlands in northeast Alberta, Canada. Mechanical site preparation (mounding and ripping) increased tree density when compared to untreated lines, despite averaging 3.8-years since treatment (vs. 22 years since disturbance for untreated). Specifically, treated lines had, on average, 12,290 regenerating tree stems/ha, which is 1.6-times more than untreated lines (7680 stems/ha) and 1.5-times more than the adjacent undisturbed forest (8240 stems/ha). Using only mechanical site preparation, treated seismic lines consistently have more regenerating trees across all four ecosites, although the higher amounts of stems that were observed on treated poor fens are not significant when compared to untreated or adjacent undisturbed reference stands.

Late Holocene deforestation and tree regeneration in the forest–tundra of Québec

Nature ◽  
1985 ◽  
Vol 313 (6003) ◽  
pp. 570-572 ◽  
Author(s):  
Serge Payette ◽  
Réjean Gagnon
Keyword(s):  
Late Holocene ◽  
Tree Regeneration ◽  
Forest Tundra

scholarly journals Boreal tree regeneration after fire and fuelwood harvesting in coastal Nunatsiavut

2020 ◽  
Vol 6 (4) ◽  
pp. 384-403
Author(s):  
Lucas Brehaut ◽  
Carissa D. Brown
Keyword(s):  
Boreal Forest ◽  
Forest Regeneration ◽  
Abies Balsamea ◽  
Tree Regeneration ◽  
Tree Age ◽  
Published Data ◽  
Stem Density ◽  
Forest Stands ◽  
Seedling Regeneration ◽  
The People

Consecutive landscape-scale disturbances are known to influence boreal forest regeneration, yet few published data exist on the compounding effects of natural and anthropogenic disturbance on regeneration in subarctic forests. We conducted a dendroecological study of eastern coastal boreal forest regeneration two decades after fire at three subarctic forest stands that are important sources of fuelwood for the people of Nunatsiavut (Labrador, Canada). We quantified spruce (Picea spp.) and balsam fir (Abies balsamea (L.) Mill.) seedling regeneration, standing dead tree density, trees harvested within burned forests, and aged proximal unburned stands. Age of unburned forest varied with site; however, each exhibited continuous regeneration over several decades. Despite low seedling regeneration at each site (stems·m−2; less than 35% of pre-fire stem density), model results indicated harvesting post-fire did not impact seedling regeneration. Findings suggest a negative pressure on seedling abundance from increased presence of tall multi-stemmed shrubs, yet we argue that because stands exhibit a range in tree age, shrubs may be a set of early successional species rather than indicating a change in successional trajectory. Examination of a larger chronosequence within coastal forest stands of Nunatsiavut is warranted to further understand forest regeneration in the eastern subarctic under changing disturbance regimes.

Ultra-high resolution assessment of potential impacts of vegetation shadows on satellite-derived spectral signals from small thermokarst lakes in the boreal forest-tundra transition zone (subarctic Canada)

2021 ◽  
Author(s):  
Pedro Freitas ◽  
Gonçalo Vieira ◽  
Carla Mora ◽  
João Canário ◽  
Diogo Folhas ◽  
...  
Keyword(s):  
High Resolution ◽  
Boreal Forest ◽  
Transition Zone ◽  
Satellite Data ◽  
Thermokarst Lakes ◽  
Forest Tundra ◽  
Permafrost Thaw ◽  
Spectral Signal ◽  
Tree Communities ◽  
Additional Support

<p>Warming of the circumpolar north is accelerating permafrost thaw, with implications for landscapes, hydrology, ecosystems and the global carbon cycle. In subarctic Canada, abrupt permafrost thaw is creating widespread thermokarst lakes. Little attention has been given to small waterbodies with area less than 10,000 m<sup>2</sup>, yet these are biogeochemically more active than larger lakes. Additionally, the landscapes where they develop show intense shrubification and terrestrialization processes, with increases in area and height of shrub and tree communities. Tall vegetation that is colonizing waterbody margins can cast shadows that impact productivity, thermal regime and the water spectral signal, which in satellite data generates pixels with mixed signatures between sunlit and shaded surfaces. We undertook UAV surveys using optical and multispectral sensors at long-term monitoring sites of the Center for Northern Studies (CEN) in subarctic Canada, from the sporadic (SAS/KWAK) to the discontinuous (BGR) permafrost zones in the boreal forest-tundra transition zone. This ultra-high spatial resolution data enabled spectral characterization and 3D reconstruction of the study areas. Ultra-high resolution digital surface models were produced to model shadowing at satellite overpass time (WorldView, PlanetScope and Sentinel-2). We then analyzed the impacts of surrounding vegetation and cast shadows on lake surface spectral reflectance derived from satellite imagery. Ultra-high resolution UAV data allows generating accurate shadow models and can be used to improve the assessment of errors and accuracy of satellite data analysis. Particularly, we identify different spectral signal impacts of cast shadows according to lake color, which highlight the need for special attention of this issue onto lakes with more turbidity.</p><p>This research is funded by the Portuguese Foundation for Science and Technology (FCT) under the project THAWPOND (PROPOLAR), by the Centre of Geographical Studies (FCT I.P. UIDB/00295/2020 and UIDP/00295/2020), with additional support from ArcticNet (NCE), Sentinel North (CFREF) and CEN and is a contribution to T-MOSAiC. PF is funded by FCT (SFRH/BD/145278/2019).</p>

Winter habitat use by ptarmigan, snowshoe hares, red foxes, and river otters in the boreal forest – tundra transition zone of western Quebec

1995 ◽  
Vol 73 (4) ◽  
pp. 755-764 ◽  
Author(s):  
Mario St-Georges ◽  
Simon Nadeau ◽  
Daniel Lambert ◽  
Robert Décarie
Keyword(s):  
Boreal Forest ◽  
Transition Zone ◽  
Species Abundance ◽  
Habitat Type ◽  
Riparian Habitat ◽  
Red Foxes ◽  
Winter Habitat ◽  
Forest Tundra ◽  
River Otters ◽  
Snowshoe Hares

We investigated species–habitat relationships of the midsized fauna inhabiting the transition zone between the boreal forest and forest tundra of subarctic Quebec. Data were collected during a winter aerial track survey of 46 randomly selected 25-km2 plots. The presence of species tracks and habitat variables were recorded for each 1-km section of riparian edge habitat within a plot. Sections of non-riparian habitat were also surveyed. Logistic regression was used to construct habitat models for ptarmigan (Lagopus spp.), snowshoe hares (Lepus americanus), red foxes (Vulpes vulpes), and river otters (Lutra canadensis). Species' habitat type selection was studied by comparing use and availability. Kendall's correlation coefficients were computed to analyze interrelations between variables. Significant logistic regressions were obtained for each species. The index of rank correlation between the observed responses and predicted probabilities for all pairs of observations ranged from 0.67 for ptarmigan to 0.84 for river otters. Species abundance was negatively associated with latitude except for that of snowshoe hare, which showed a stronger negative link with open habitat. For all species, distribution was not proportional to the frequency of occurrence of habitat types. Non-riparian habitat was either avoided or not significantly preferred by all species. Herbivorous species and river otter selected edge habitats along watercourses. Our study suggests that differences presented by the forest tundra and boreal forest are of importance for wildlife.

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