Potential shifts in dominant forest cover in interior Alaska driven by variations in fire severity

2011 ◽  
Vol 21 (7) ◽  
pp. 2380-2396 ◽  
Author(s):  
K. Barrett ◽  
A. D. McGuire ◽  
E. E. Hoy ◽  
E. S. Kasischke
Keyword(s):  
Forest Cover ◽  
Fire Severity ◽  
Interior Alaska ◽  
In Fire ◽  
Potential Shifts

scholarly journals Sources and Sinks of Carbon in Boreal Ecosystems of Interior Alaska : A Review

2021 ◽  
Author(s):  
Thomas A. Douglas ◽  
Christopher A. Hiemstra ◽  
Miriam C. Jones ◽  
Jeffrey R. Arnold
Keyword(s):  
Carbon Cycle ◽  
Forest Succession ◽  
Fire Severity ◽  
Carbon Sources ◽  
Boreal Ecosystems ◽  
Hydrologic Processes ◽  
Sources And Sinks ◽  
Interior Alaska ◽  
Discontinuous Permafrost ◽  
In Fire

Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in soil and vegetation. The roles of fire, forest succession, and the presence/absence of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in boreal ecosystems for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle, this paper was developed incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. The objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution from 45° to 83° north.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Basal Area ◽  
Conifer Forest ◽  
Fuel Loading ◽  
Early Season ◽  
Late Season ◽  
Fuel Loads ◽  
In Fire

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

Mapping fire regime ecoregions in California

2020 ◽  
Vol 29 (7) ◽  
pp. 595 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
Fire Regime ◽  
Fire Severity ◽  
Fire Regimes ◽  
Unsupervised Classification ◽  
Fire Frequency ◽  
The State ◽  
Reduction Strategies ◽  
Lower Variability ◽  
Fire Characteristics ◽  
In Fire

The fire regime is a central framing concept in wildfire science and ecology and describes how a range of wildfire characteristics vary geographically over time. Understanding and mapping fire regimes is important for guiding appropriate management and risk reduction strategies and for informing research on drivers of global change and altered fire patterns. Most efforts to spatially delineate fire regimes have been conducted by identifying natural groupings of fire parameters based on available historical fire data. This can result in classes with similar fire characteristics but wide differences in ecosystem types. We took a different approach and defined fire regime ecoregions for California to better align with ecosystem types, without using fire as part of the definition. We used an unsupervised classification algorithm to segregate the state into spatial clusters based on distinctive biophysical and anthropogenic attributes that drive fire regimes – and then used historical fire data to evaluate the ecoregions. The fire regime ecoregion map corresponded well with the major land cover types of the state and provided clear separation of historical patterns in fire frequency and size, with lower variability in fire severity. This methodology could be used for mapping fire regimes in other regions with limited historical fire data or forecasting future fire regimes based on expected changes in biophysical characteristics.

Postfire seed rain of black spruce, a semiserotinous conifer, in forests of interior Alaska

2009 ◽  
Vol 39 (8) ◽  
pp. 1575-1588 ◽  
Author(s):  
Jill Johnstone ◽  
Leslie Boby ◽  
Emily Tissier ◽  
Michelle Mack ◽  
Dave Verbyla ◽  
...  
Keyword(s):  
Structural Equation ◽  
Black Spruce ◽  
Fire Severity ◽  
Seed Viability ◽  
Basal Area ◽  
Seed Rain ◽  
Equation Modeling ◽  
Viable Seed ◽  
Interior Alaska ◽  
Total Seed

The availability of viable seed can act as an important constraint on plant regeneration following disturbance. This study presents data on seed quantity and quality for black spruce ( Picea mariana (Mill.) B.S.P.), a semiserotinous conifer that dominates large areas of North American boreal forest. We sampled seed rain and viability for 2 years after fire (2005–2007) in 39 sites across interior Alaska that burned in 2004. All sites were dominated by black spruce before they burned. Structural equation modeling was used to assess the relative importance of prefire spruce abundance, topography effects, canopy fire severity, and distance to unburned stands in explaining variations in black spruce seed rain. Prefire basal area of spruce that remained standing after fire was a significant predictor of total seed rain, but seed viability was more strongly related to site elevation, canopy fire severity, and distances to unburned stands. Although positive relations between tree basal area and the size of the aerial seed bank may place a first constraint on seed availability, accurate prediction of postfire viable seed rain for serotinous conifers also requires consideration of the effects of abiotic stress and canopy fire severity on seed viability.

Refuges for birds in fire-prone landscapes: The influence of fire severity and fire history on the distribution of forest birds

2014 ◽  
Vol 318 ◽  
pp. 110-121 ◽  
Author(s):  
Natasha M. Robinson ◽  
Steven W.J. Leonard ◽  
Andrew F. Bennett ◽  
Michael F. Clarke
Keyword(s):  
Fire History ◽  
Fire Severity ◽  
Forest Birds ◽  
In Fire

scholarly journals Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

Elem Sci Anth ◽  
2014 ◽  
Vol 2 ◽  
Author(s):  
Thomas A. Douglas ◽  
Miriam C. Jones ◽  
Christopher A. Hiemstra ◽  
Jeffrey R. Arnold
Keyword(s):  
Carbon Cycle ◽  
Forest Succession ◽  
Fire Severity ◽  
Research Question ◽  
Carbon Sources ◽  
Ecosystem Processes ◽  
Boreal Ecosystems ◽  
Sources And Sinks ◽  
Interior Alaska ◽  
Discontinuous Permafrost

Abstract Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in soil and vegetation. The roles of fire, forest succession, and the presence (or absence) of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in boreal ecosystems for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle we developed this review paper by incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We surveyed estimates of aboveground and belowground carbon stocks for interior Alaska boreal ecosystems and summarized methane and carbon dioxide fluxes. These data have been converted into similar units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance. A novel research question is how compounding disturbances affect carbon sources and sinks associated with boreal ecosystem processes. Finally, we provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution from 45° to 83° north.

scholarly journals Identifying Post-Fire Recovery Trajectories and Driving Factors Using Landsat Time Series in Fire-Prone Mediterranean Pine Forests

2020 ◽  
Vol 12 (9) ◽  
pp. 1499 ◽  
Author(s):  
Alba Viana-Soto ◽  
Inmaculada Aguado ◽  
Javier Salas ◽  
Mariano García
Keyword(s):  
Time Series ◽  
Fire Severity ◽  
Driving Factors ◽  
Pine Forests ◽  
Recovery Rates ◽  
Tasseled Cap ◽  
Successional Stages ◽  
Mediterranean Pine ◽  
Recovery Dynamics ◽  
In Fire

Wildfires constitute the most important natural disturbance of Mediterranean forests, driving vegetation dynamics. Although Mediterranean species have developed ecological post-fire recovery strategies, the impacts of climate change and changes in fire regimes may endanger their resilience capacity. This study aims at assessing post-fire recovery dynamics at different stages in two large fires that occurred in Mediterranean pine forests (Spain) using temporal segmentation of the Landsat time series (1994–2018). Landsat-based detection of Trends in Disturbance and Recovery (LandTrendr) was used to derive trajectory metrics from Tasseled Cap Wetness (TCW), sensitive to canopy moisture and structure, and Tasseled Cap Angle (TCA), related to vegetation cover gradients. Different groups of post-fire trajectories were identified through K-means clustering of the Recovery Ratios (RR) from fitted trajectories: continuous recovery, continuous recovery with slope changes, continuous recovery stabilized and non-continuous recovery. The influence of pre-fire conditions, fire severity, topographic variables and post-fire climate on recovery rates for each recovery category at successional stages was analyzed through Geographically Weighted Regression (GWR). The modeling results indicated that pine forest recovery rates were highly sensitive to post-fire climate in the mid and long-term and to fire severity in the short-term, but less influenced by topographic conditions (adjusted R-squared ranged from 0.58 to 0.88 and from 0.54 to 0.93 for TCA and TCW, respectively). Recovery estimation was assessed through orthophotos, showing a high accuracy (Dice Coefficient ranged from 0.81 to 0.97 and from 0.74 to 0.96 for TCA and TCW, respectively). This study provides new insights into the post-fire recovery dynamics at successional stages and driving factors. The proposed method could be an approach to model the recovery for the Mediterranean areas and help managers in determining which areas may not be able to recover naturally.

scholarly journals Near-complete loss of fire-resistant primary tropical forest cover in Sumatra and Kalimantan

2021 ◽  
Author(s):  
Tadas Nikonovas ◽  
Allan Spessa ◽  
Stefan Doerr ◽  
Gareth Clay ◽  
Symon Mezbuhaddin
Keyword(s):  
Forest Cover ◽  
Fire Regimes ◽  
Forest Edge ◽  
Complete Loss ◽  
Primary Forest ◽  
Peatland Restoration ◽  
Future Global Warming ◽  
Drought Conditions ◽  
In Fire ◽  
Primary Forests

<p>Deforestation in Indonesia in recent decades has made increasingly large parts of the region vulnerable to fires. Burning is particularly widespread in deforested peatlands, and it leads to globally significant carbon emissions. Here we use satellite-based observations to assess loss and fragmentation of primary forests and associated changes in fire regimes in Sumatra and Kalimantan between 2001 and 2019. We find that fires did not penetrate undisturbed primary forest areas deeper than two kilometres from the forest edge irrespective of drought conditions. However, fire-resistant forest now covers only 3% of peatlands and 4.5% of non-peatlands; the majority of the remaining primary forests are severely fragmented or degraded due to proximity to the forest edge. We conclude that protection and regeneration of the remaining blocks of contiguous primary forest, as well as peatland restoration, are urgently needed to mitigate the impacts of potentially more frequent fire events under future global warming.</p>

Effect of fire severity on long-term occupancy of burned boreal conifer forests by saproxylic insects and wood-foraging birds

2010 ◽  
Vol 19 (4) ◽  
pp. 500 ◽  
Author(s):  
Antoine Nappi ◽  
Pierre Drapeau ◽  
Michel Saint-Germain ◽  
Virginie A. Angers
Keyword(s):  
Boreal Forests ◽  
Fire Severity ◽  
Fire Regimes ◽  
Conifer Forests ◽  
Saproxylic Insects ◽  
Dead Trees ◽  
Brown Creeper ◽  
Canadian Boreal Forest ◽  
In Fire

Fire severity can vary greatly within and among burns, even in the Canadian boreal forest where fire regimes consist mostly of stand-replacing fires. We investigated the effects of fire severity on the long-term occupancy of burns by (i) saproxylic insects and (ii) three wood-foraging birds. Based on observations made 6 to 11 years after fire in burned conifer forests that varied in fire severity in Quebec, Canada, our results indicate that low-severity portions of the burns likely provided snag conditions suitable for the long-term presence of deadwood-associated insects and birds. The black-backed woodpecker, a post-fire forest specialist, was still abundant 6 and 8 years after fire. This pattern was likely explained by the persistence of several saproxylic insect species that are associated with recently dead trees and by the positive effect of lower fire severity on the abundance of Arhopalus foveicollis, a cerambycid with a long life cycle in dead wood. The American three-toed woodpecker and the brown creeper, and their associated prey (Scolytinae beetles), were more abundant in burned stands of lower v. higher severity. We conclude that less severely burned snags and stands within high-severity burns may favour the long-term presence of trophic webs that involve saproxylic insects and wood-foraging birds in burned boreal forests.

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