Initial Succession After Wildfire in Dry Boreal Forests of Northwestern North America

2021 ◽  
Author(s):  
Denyse Dawe ◽  
Marc-André Parisien ◽  
Angeline Van Dongen ◽  
Ellen Whitman
Keyword(s):  
North America ◽  
Plant Community ◽  
Boreal Forests ◽  
Regional Climate ◽  
Relative Equilibrium ◽  
Plant Cover ◽  
Tree Regeneration ◽  
Vegetation Changes ◽  
Tree Seedling ◽  
Species Dominance

Abstract Wildfires in the boreal forest of North America are generally stand renewing, with the initial phase of vegetation recovery often governing the vegetation trajectory for decades. Here, we investigate post-fire vegetation changes in dry boreal forests of the Northwest Territories, Canada, during the first five years following the unusually severe 2014 wildfire season. We sampled post-fire tree regeneration and the overall plant community at one, three, and five years post-fire across different fire severities and stand types within fires that burned in 2014. Post-fire trajectories of tree recruitment, cover by plant functional types, and plant diversity varied widely among sampled stands, as well as among years post-fire. Tree seedling density reaches relative equilibrium by three years post-fire, whereas trends in understory plant cover and understory species assemblages suggest an ongoing change that will extend beyond five years of observation. In almost half of sampled stands, the composition of recruited trees differs from that of the pre-fire stand, suggesting a change in tree-species dominance. An analysis of regional climate reveals a significant, albeit spatially variable, warming and drying trend that will further accelerate forest-stand transformation through both climate drivers of plant community composition and indirectly through increasing fire activity. While the 2014 wildfires enhanced the structural and compositional heterogeneity of the region, they also triggered vegetation changes that are likely to be persistent. As such, this study exemplifies the speed and variability that characterizes post-fire stand development in a strongly moisture-limited part of North America.

scholarly journals High-latitude cooling associated with landscape changes from North American boreal forest fires

2013 ◽  
Vol 10 (2) ◽  
pp. 699-718 ◽  
Author(s):  
B. M. Rogers ◽  
J. T. Randerson ◽  
G. B. Bonan
Keyword(s):  
North America ◽  
Boreal Forest ◽  
High Latitude ◽  
Forest Fires ◽  
Boreal Forests ◽  
Regional Climate ◽  
Forest Composition ◽  
Energy Budgets ◽  
Functional Variation ◽  
Greenhouse Gasses

Abstract. Fires in the boreal forests of North America are generally stand-replacing, killing the majority of trees and initiating succession that may last over a century. Functional variation during succession can affect local surface energy budgets and, potentially, regional climate. Burn area across Alaska and Canada has increased in the last few decades and is projected to be substantially higher by the end of the 21st century because of a warmer climate with longer growing seasons. Here we simulated changes in forest composition due to altered burn area using a stochastic model of fire occurrence, historical fire data from national inventories, and succession trajectories derived from remote sensing. When coupled to an Earth system model, younger vegetation from increased burning cooled the high-latitude atmosphere, primarily in the winter and spring, with noticeable feedbacks from the ocean and sea ice. Results from multiple scenarios suggest that a doubling of burn area would cool the surface by 0.23 ± 0.09 °C across boreal North America during winter and spring months (December through May). This could provide a negative feedback to winter warming on the order of 3–5% for a doubling, and 14–23% for a quadrupling, of burn area. Maximum cooling occurs in the areas of greatest burning, and between February and April when albedo changes are largest and solar insolation is moderate. Further work is needed to integrate all the climate drivers from boreal forest fires, including aerosols and greenhouse gasses.

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.

Impacts of erosion control treatments on native vegetation recovery after severe wildfire in the Eastern Cascades, USA

2010 ◽  
Vol 19 (4) ◽  
pp. 490 ◽  
Author(s):  
Erich K. Dodson ◽  
David W. Peterson ◽  
Richy J. Harrod
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Native Species ◽  
Plant Cover ◽  
Plant Species Richness ◽  
Tree Regeneration ◽  
Vegetation Recovery ◽  
Native Vegetation ◽  
Individual Plant ◽  
Native Plant

Slope stabilisation treatments like mulching and seeding are used to increase soil cover and reduce runoff and erosion following severe wildfires, but may also retard native vegetation recovery. We evaluated the effects of seeding and fertilisation on the cover and richness of native and exotic plants and on individual plant species following the 2004 Pot Peak wildfire in Washington State, USA. We applied four seeding and three fertilisation treatments to experimental plots at eight burned sites in spring 2005 and surveyed vegetation during the first two growing seasons after fire. Seeding significantly reduced native non-seeded species richness and cover by the second year. Fertilisation increased native plant cover in both years, but did not affect plant species richness. Seeding and fertilisation significantly increased exotic cover, especially when applied in combination. However, exotic cover and richness were low and treatment effects were greatest in the first year. Seeding suppressed several native plant species, especially disturbance-adapted forbs. Fertilisation, in contrast, favoured several native understorey plant species but reduced tree regeneration. Seeding, even with native species, appears to interfere with the natural recovery of native vegetation whereas fertilisation increases total plant cover, primarily by facilitating native vegetation recovery.

scholarly journals Potentials of Natural Tree Regeneration after Clearcutting in Subalpine Forests

2008 ◽  
Vol 23 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Juergen Kreyling ◽  
Andreas Schmiedinger ◽  
Ellen Macdonald ◽  
Carl Beiekuhnlein
Keyword(s):  
Natural Regeneration ◽  
Pinus Contorta ◽  
Woody Debris ◽  
Negative Relationship ◽  
Forest Edge ◽  
Tree Regeneration ◽  
Tree Seedlings ◽  
Tree Seedling ◽  
Engelmann Spruce ◽  
Understory Plant

Abstract Regeneration of interior mountain forests still is not adequately understood, although these forests are subject to intensified use over the last decades. We examined factors influencing the success of natural tree regeneration after harvesting in the Engelmann spruce–subalpine fir zone of the Monashee Mountains, British Columbia, Canada. Distance from the forest edge was an important factor for regeneration; at distances exceeding 70 m from the forest edge only 50% of plots showed sufficient natural regeneration to meet stocking targets compared with 90% of plots closer to forest edges. Seedling density and growth were superior in the more protected southern portions of clearcuts. Seedling growth was less in plots containing high cover of downed woody debris. There was no relationship between understory plant diversity or composition and tree seedling regeneration. However, cover of fireweed (Epilobium angustifolium) had a significant negative relationship with density but not growth of tree seedlings, particularly for lodgepole pine (Pinus contorta var. latifolia). Cover of fireweed decline substantially within the first 10 years after clearcutting. We conclude that natural regeneration of trees has potential to help achieve stocking targets and also to maintain natural diversity of tree species if spatial constraints, especially thresholds in clearcut size, are considered.

scholarly journals Climate on tundra and thoughts on causes of regional climate differences

2000 ◽  
Vol 31 ◽  
pp. 10-14 ◽  
Author(s):  
Atsumu Ohmura
Keyword(s):  
West Coast ◽  
Boreal Forests ◽  
Regional Climate ◽  
Global Scale ◽  
Scientific Investigations ◽  
Causal Processes ◽  
Mcgill University ◽  
Axel Heiberg Island ◽  
Fundamental Consideration

AbstractThe Axel Heiberg Island Expedition of McGill University, Montreal, Canada, led by the late Fritz Müller was the cradle for a number of scientific investigations, not all of them glaciological. During the four years 1969–72, the tundra climate was investigated in the Expedition Area, encompassing about 100 km2 on the mid-west coast of Axel Heiberg Island, Nunavut, Canada. This series of studies identified the main features of the tundra climate, clarified its causal processes and contributed to an understanding of the differences between tundra climates and those of the neighboring regions with glaciers, ocean surfaces and boreal forests. A fundamental consideration of climate processes on a global scale was conceived during this time. Some significant results are recorded here to commemorate Fritz Müller’s contributions as a polar scientist and a university educator.

scholarly journals Soil Properties and Plant Community Changes along a Goat Grazing Intensity Gradient in an Open Canopy Oak Forest

2013 ◽  
Vol 41 (2) ◽  
pp. 567 ◽  
Author(s):  
Aimilia LEMPESI ◽  
Apostolos P. KYRIAZOPOULOS ◽  
Michail ORFANOUDAKIS ◽  
Georgios KORAKIS
Keyword(s):  
Soil Properties ◽  
Plant Community ◽  
Management Practices ◽  
Plant Cover ◽  
Grazing Intensity ◽  
Oak Forest ◽  
Goat Grazing ◽  
Open Canopy ◽  
Grazing Intensities ◽  
Soil Measurements

Understanding how the management practices of silvopastoral systems affect the long-term sustainability of oak ecosystems and what their influence is on nutrient cycling and plant community, is of great interest. The aim of this study was to examine the effects of relative grazing intensity on soil properties and on vegetation characteristics in an open canopy oak forest dominated by Quercus frainetto. The research was conducted in the area of Pentalofos, which is located in Evros region, north-eastern Greece and is grazed by goats. The distance from a goat corral was used to represent relative grazing intensity. In June 2011, soil and vegetation samples were collected along transects placed at 50, 150, 300, 600 and 1200 m from the goat corral, running perpendicular to three replicates. Soil measurements included pH, phosphorous (P) and nitrogen (N) concentrations while vegetation measurements included plant cover, species composition and diversity. Plant cover was not significantly different among grazing intensities. Species diversity, especially of the woody vegetation layer, was significantly higher in the light grazing intensity in comparison to both the heavy and the very light grazing. Heavy grazing reduced soil organic matter while it increased total nitrogen. Grazing intensity did not affect available P and soil pH. Light to moderate goat grazing could ameliorate floristic diversity and increase sustainability of oak forests in the Mediterranean region.

scholarly journals Mountain pastures of Qilian Shan: plant communities, grazing impact and degradation status (Gansu province, NW China)

Hacquetia ◽  
2016 ◽  
Vol 15 (2) ◽  
pp. 21-35 ◽  
Author(s):  
Alina Baranova ◽  
Udo Schickhoff ◽  
Shunli Wang ◽  
Ming Jin
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Plant Cover ◽  
Management Strategies ◽  
Detrended Correspondence Analysis ◽  
Gansu Province ◽  
Grazing Impact ◽  
Vegetation Patterns ◽  
Pasture Management ◽  
Nw China

Abstract Environmental degradation of pasture areas in the Qilian Mountains (Gansu province, NW China) has increased in recent years. Soil erosion and loss of biodiversity caused by overgrazing is widespread. Changes in plant cover, however, have not been analysed so far. The aim of this paper is to identify plant communities and to detect grazing-induced changes in vegetation patterns. Quantitative and qualitative relevé data were collected for community classification and to analyse gradual changes in vegetation patterns along altitudinal and grazing gradients. Detrended correspondence analysis (DCA) was used to analyse variation in relationships between vegetation, environmental factors and differential grazing pressure. The results of the DCA showed apparent variation in plant communities along the grazing gradient. Two factors - altitude and exposure - had the strongest impact on plant community distribution. Comparing monitoring data for the most recent nine years, a trend of pasture deterioration, plant community successions and shift in dominant species becomes obvious. In order to increase grassland quality, sustainable pasture management strategies should be implemented.

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