Download or read book Remote Sensing of Burn Severity and the Interactions Between Burn Severity Topography and Vegetation in Interior Alaska written by Justin Frederick Epting and published by . This book was released on 2004 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A variety of single-band, band ratio, vegetation index, and multivariate algorithms were evaluated for mapping burn severity using Landsat TM and ETM+ imagery across four burns in interior Alaska. The Normalized Burn Ratio (NBR) outperformed all algorithms, both when tested as a single post-fire value and when tested as a differenced (prefire-postfire) value. The NBR was then used to map burn severity at a historical burn near Yukon-Charley Rivers National Preserve and a time-series of images from 1986 to 2002 was analyzed to investigate interactions between vegetation, burn severity, and topography. Strong interactions existed between vegetation and burn severity, but the only topographic variable that had a significant relationship with burn severity was elevation, presumably due to the strong control of elevation on vegetation type. The highest burn severity occurred in spruce forest, while the lowest occurred in broadleaf forest. Areas with high burn severity experienced disproportionately more shifts toward spruce woodland and shrub classes, while areas with low to moderate severity were less likely to change vegetation type. Finally, vegetation recovery, estimated using a remotely-sensed vegetation index, peaked between 8-14 years post-fire, and recovery was highest for areas with the highest burn severity"--Leaf iii.
Download or read book Interactions Among Climate Fire and Vegetation in the Alaskan Boreal Forest written by Paul Arthur Duffy and published by . This book was released on 2006 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The boreal forest covers 12 million km2 of the northern hemisphere and contains roughly 40% of the world's reactive soil carbon. The Northern high latitudes have experienced significant warming over the past century and there is a pressing need to characterize the response of the disturbance regime in the boreal forest to climatic change. The interior Alaskan boreal forest contains approximately 60 million burnable hectares and, relative to the other disturbance mechanisms that exist in Alaska, fire dominates at the landscape-scale. In order to assess the impact of forecast climate change on the structure and function of the Alaskan boreal forest, the interactions among climate, fire and vegetation need to be quantified. The results of this work demonstrate that monthly weather and teleconnection indices explain the majority of observed variability in annual area burned in Alaska from 1950-2003. Human impacts and fire-vegetation interactions likely account for a significant portion of the remaining variability. Analysis of stand age distributions indicate that anthropogenic disturbance in the early 1900's has left a distinct, yet localized impact. Additionally, we analyzed remotely sensed burn severity data to better understand interactions among fire, vegetation and topography. These results show a significant relationship between burn severity and vegetation type in flat landscapes but not in topographically complex landscapes, and collectively strengthen the argument that differential flammability of vegetation plays a significant role in fire-vegetation interactions. These results were used to calibrate a cellular automata model based on the current conceptual model of interactions among weather, fire and vegetation. The model generates spatially explicit maps of simulated stand ages at 1 km resolution across interior Alaska, and output was validated using observed stand age distributions. Analysis of simulation output suggests that significant temporal variability of both the mean and variance of the stand age distribution is an intrinsic property of the stand age distributions of the Alaskan boreal forest. As a consequence of this non-stationarity, we recommend that simulation based methods be used to analyze the impact of forecast climatic change on the structure and function of the Alaskan boreal forest"--Leaf iii.
Download or read book Climate induced Changes in Ecological Dynamics of the Alaskan Boreal Forest written by Dana Rachel Nossov Brown and published by . This book was released on 2016 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: A warming climate is expected to cause widespread thawing of discontinuous permafrost, and the co-occurrence of wildfire may function to exacerbate this process. Here, I examined the vulnerability of permafrost to degradation from fire disturbance as it varies across different landscapes of the Interior Alaskan boreal forest using a combination of observational, modeling, and remote sensing approaches. Across all landscapes, the severity of burning strongly influenced both post-fire vegetation and permafrost degradation. The thickness of the remaining surface organic layer was a key control on permafrost degradation because its low thermal conductivity limits ground heat flux. Thus, variation in burn severity controlled the local distribution of near-surface permafrost. Mineral soil texture and permafrost ice content interacted with climate to influence the response of permafrost to fire. Permafrost was vulnerable to deep thawing after fire in coarse-textured or rocky soils throughout the region; low ice content likely enabled this rapid thawing. After thawing, increased drainage in coarse-textured soils caused reductions in surface soil moisture, which contributed to warmer soil temperatures. By contrast, permafrost in fine-textured soils was resilient to fire disturbance in the silty uplands of the Yukon Flats ecoregion, but was highly vulnerable to thawing in the silty lowlands of the Tanana Flats. The resilience of silty upland permafrost was attributed to higher water content of the active layer and the associated high latent heat content of the ice-rich permafrost, coupled with a relatively cold continental climate and sloping topography that removes surface water. In the Tanana Flats, permafrost in silty lowlands thawed after fire despite high water and ice content of soils. This thawing was associated with significant ground surface subsidence, which resulted in water impoundment on the flat terrain, generating a positive feedback to permafrost degradation and wetland expansion. The response of permafrost to fire, and its ecological effects, thus varied spatially due to complex interactions between climate, topography, vegetation, burn severity, soil properties, and hydrology. The sensitivity of permafrost to fire disturbance has also changed over time due to variation in weather at multi-year to multi-decadal time scales. Simulations of soil thermal dynamics showed that increased air temperature, increased snow accumulation, and their interactive effects, have since the 1970s caused permafrost to become more vulnerable to talik formation and deep thawing from fire disturbance. Wildfire coupled with climate change has become an important driver of permafrost loss and ecological change in the northern boreal forest. With continued climate warming, we expect fire disturbance to accelerate permafrost thawing and reduce the likelihood of permafrost recovery. This regime shift is likely to have strong effects on a suite of ecological characteristics of the boreal forest, including surface energy balance, soil moisture, nutrient cycling, vegetation composition, and ecosystem productivity.
Download or read book Annual Report written by University of Alaska Fairbanks. Agricultural and Forestry Experiment Station and published by . This book was released on 2004 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advancing Wildfire Fuel Mapping and Burn Severity Assessment in Alaskan Boreal Forest Using Multi sensor Remote Sensing written by Christopher William Smith and published by . This book was released on 2021 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wildfires in Alaska have been increasing in frequency, size, and intensity putting a strain on communities across the state, especially remote communities lacking firefighting infrastructure to address large scale fire events. Advances in remote sensing techniques and data provide an opportunity to generate high quality map products that can better inform fire managers to allocate resources to areas of most risk and inform scientists how to predict and understand fire behavior. The overarching goal of this thesis is therefore to build insight into methods that can be applied to create highly detailed fire statistic map products in Alaska. To address this overarching goal we tested several methods for generating fire fuel, burn severity, and wildfire hazard maps that were validated using data collected in the field. Applying the Random Forest classifier on Airborne Visible/ Infrared Imaging Spectrometer Next-Generation (AVIRIS-NG) hyperspectral data we were able to produce a fire fuel map with an 81% accuracy. We then tested two supervised machine learning classifiers, post fire standard spectral indices, and differenced spectral indices for their performance in assessing burn severity. We found that supervised machine learning classifiers outperform other algorithms when there is an adequate amount of training data. Using the support vector machine and random forest classifiers we were able to generate burn severity maps with 83% accuracy at the 2019 Shovel Creek Fire. Lastly, we looked for a relationship between burn severity and environmental conditions prevalent during the Shovel Creek and Nugget Creek fires. Overall, these products can be used by fire managers and scientists to assess fire risk, limit the damages caused by wildfires through adequate resource allocation, and provide the guidelines for creating future high quality fire fuel maps.
Download or read book Vegetation Response to Prescribed Fire in the Kenai Mountains Alaska written by Tina V. Boucher and published by . This book was released on 2003 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Between 1977 and 1997, 4000 ha were burned to promote regeneration of tree and shrub species used for browse by moose (Alces alces) in the Kenai Mountains. Species composition was documented along burned and unburned transects at 17 prescribed burn sites. Relationships among initial vegetation composition, physical site characteristics, browse species abundance, and competitive herbaceous vegetation were examined to determine controls on browse species regeneration after prescribed burning. Browse species abundance after burning was inversely related to Calamagrostis canadensis Michx. Beauv. (bluejoint reedgrass) abundance prior to burning. Calamagrostis canadensis abundance was related to specific landscape characteristics. Depositional slopes, such as fluvial valley bottoms and toe slopes, often featured soils with deep, loamy surface horizons. Sites with these characteristics generally showed large increases in C. canadensis cover after prescribed burning, even when C. canadensis was a low percentage (3 percent) of the canopy cover prior to burning. The most important preburn variables for predicting postburn browse species abundance were preburn C. canadensis cover and the type of surficial deposit. Site conditions that are favorable to C. canadensis may be problematic for successful regeneration of browse species, especially if browse species are not present in the initial composition.
Download or read book The Effect of Burn Severity on Short term Boreal Vegetation Recovery in Interior Alaska written by Jared Wesley Oyler and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wildfire Burn Susceptibility to Non native Plant Invasions in Black Spruce Forests of Interior Alaska written by Katie Lin Villano and published by . This book was released on 2008 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: "As the climate changes, Alaska's boreal forest faces the simultaneous threats of rising invasive plant abundances and increasing area burned by wildfire. Highly flammable and widespread black spruce forest represents a boreal habitat that may be increasingly susceptible to non-native plant invasion. In other biomes, non-native plant invasions are generally greatest in high severity burns that are only a few years old. The relationship between fire and non-native plant invasion has not been investigated in the northern boreal forest. To assess the invasibility of burned black spruce forests, I used burned field sites that spanned a gradient of burn severities, moisture levels, and burn ages. I conducted both field surveys and a greenhouse experiment using soil taken from burn sites. Contrary to generalizations from other biomes, I found soils from low severity burns and burns between 10 and 20 years old support greater invasive plant growth in black spruce forests than do high severity and more recent burns. In addition, regional differences between burn complexes outweighed burn severity and site moisture in determining the invasibility of burned black spruce sites. Finally, rebounding native vegetation appears to offer burned areas a level of resistance to invasive plant establishment"--Leaf iii.
Download or read book Quantifying Burn Severity in Forests of the Interior Pacific Northwest written by Saba Juliet Saberi and published by . This book was released on 2019 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate quantification of burn severity, or the magnitude of fire-caused ecological change, is important, especially as the climate warms and associated changes to fire regimes unfold. The purpose of this thesis is to explore relationships between different methods of burn severity quantification in the Interior Pacific Northwest (IPNW) (Chapter 2), and to see if these relationships differ in short interval reburns (Chapter 3). Burn severity is commonly assessed in the field by forest managers and scientists using semi-quantitative ordinal ocular estimates such as the Composite Burn Index (CBI). Yet, because CBI and direct quantitative measures of burn severity are rarely collected together, how CBI relates to individual measures of burn severity has not been widely tested. Further, how CBI relates to different satellite indices of burn severity varies and has not been tested across many regions. I address these knowledge gaps by comparing CBI to eight individual quantitative field measures of burn severity 1-year post burn from 315 plots across 14 fires in the IPNW. Using zero and one inflated beta regression models and area under the receiver operating curve (AUC) for model comparison, I tested the relationship between CBI and individual field measures, and between CBI and three satellite indices. Canopy measures were best captured by CBI while surface measures were not well captured by CBI. Furthermore, the three remotely sensed indices were nearly equal in their relationship with burn severity in the region. The strong correspondence between CBI and most individual measures of burn severity suggests that CBI, as a relatively simple field assessment, could be used to infer individual components of burn severity in burned landscapes. However, some variables were not captured by CBI (e.g., deep char, or charred bole surface that is scaly in appearance) and could be collected in the field to augment CBI. In Chapter 3, I tested to see if the relationships between individual field metrics and 1) CBI and 2) RdNBR differed if the fire was a short interval reburn, and when so, if the first fire was stand replacing or not. This research question addresses the gap in understanding of if burn severity indices in reburns provide the same information as they do in single burns. While reburns are a normal part of fire regimes, in some areas they represent a return to historical fire frequency, while in others they raise significant ecological questions about their effects on forest structure and function. I found the relationship between canopy measures (e.g. change in live canopy cover, tree mortality, char heights) and CBI were mostly similar between single burns and reburns. However, the relationships between CBI and floor measures of burn severity differ in short interval reburns when the first fire was non-stand replacing. CBI's inability to capture surface measures may be because surface measures are often related to pre-fire vegetation and general cover in the understory, and CBI is a post-fire measurement. Relationships between canopy measures and RdNBR were also mostly similar between single burns and reburns, and RdNBR over-predicted surface char in reburns where the first fire was non-stand replacing. RdNBR may be unable to capture surface char in reburns where the first fire was non-stand replacing because these areas may experience frequent light surface fire, where satellite sensors only capture the spectral signatures from unchanged tree canopies. In a non-stand replacing fire, the understory may be frequently opening up and re-sprouting post fire, and it may be difficult for satellite sensors to capture the spectral indices in the understory. Deep char could not be modeled by either CBI or RdNBR, suggesting that neither metric can capture deep char. My study suggests that current canopy measures of burn severity are accurate in reburns, but that interpretation of reburn burn severity on the forest floor should be made with caution.
Download or read book Earth Observation of Wildland Fires in Mediterranean Ecosystems written by Emilio Chuvieco and published by Springer Science & Business Media. This book was released on 2009-09-25 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wildland fires are becoming one of the most critical environmental factors affecting a wide range of ecosystems worldwide. In Mediterranean ecosystems (including also South-Africa, California, parts of Chile and Australia), wildland fires are recurrent phenomena every summer, following the seasonal drought. As a result of changes in traditional land use practices, and the impact of recent climate warming, fires have more negative impacts in the last years, threatening lives, socio-economic and ecological values. The book describes the ecological context of fires in the Mediterranean ecosystems, and provides methods to observe fire danger conditions and fire impacts using Earth Observation and Geographic Information System technologies.
Download or read book Spatial Modeling in GIS and R for Earth and Environmental Sciences written by Hamid Reza Pourghasemi and published by Elsevier. This book was released on 2019-01-18 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatial Modeling in GIS and R for Earth and Environmental Sciences offers an integrated approach to spatial modelling using both GIS and R. Given the importance of Geographical Information Systems and geostatistics across a variety of applications in Earth and Environmental Science, a clear link between GIS and open source software is essential for the study of spatial objects or phenomena that occur in the real world and facilitate problem-solving. Organized into clear sections on applications and using case studies, the book helps researchers to more quickly understand GIS data and formulate more complex conclusions. The book is the first reference to provide methods and applications for combining the use of R and GIS in modeling spatial processes. It is an essential tool for students and researchers in earth and environmental science, especially those looking to better utilize GIS and spatial modeling. Offers a clear, interdisciplinary guide to serve researchers in a variety of fields, including hazards, land surveying, remote sensing, cartography, geophysics, geology, natural resources, environment and geography Provides an overview, methods and case studies for each application Expresses concepts and methods at an appropriate level for both students and new users to learn by example
Download or read book Preliminary Results of Experimental Fires in the Black Spruce Type of Interior Alaska written by Leslie A. Viereck and published by . This book was released on 1979 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earth Observation of Ecosystem Services written by Domingo Alcaraz-Segura and published by CRC Press. This book was released on 2013-11-12 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: A balanced review of differing approaches based on remote sensing tools and methods to assess and monitor biodiversity, carbon and water cycles, and the energy balance of terrestrial ecosystem. Earth Observation of Ecosystem Services highlights the advantages Earth observation technologies offer for quantifying and monitoring multiple ecosystem fun
Download or read book Examining Drivers of Post Wildfire Vegetation Dynamics Across Multiple Scales Using Time Series Remote Sensing written by Grant M. Casady and published by . This book was released on 2008 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystem response to disturbance is a function of environmental factors interacting at a number ofspatio-temporal scales. This research explored ecosystem response to wildfire as a function of local and broad-scale environmental factors using satellite based time-series remote sensing data. This topic was explored as a series of three independent but related studies. The first study focused on the evaluation of techniques for the analysis of time-series satellite data for describing post-fire vegetation trends at sites in the US, Spain, and Israel. Time-series data effectively described post-fire trends, and reference sites were valuable for differentiating between post-fire effects and other environmental factors. The use of phenological indicators derived from the time-series shows promise as a monitoring tool, but requires further investigation. The next study evaluated the influence of broad-scale climate factors on rates of post-fire vegetation regeneration across the western US. Rates of post-fire regeneration were higher with increased precipitation and higher minimum temperatures. Changes in climate are likely to result in shifts in post-fire vegetation dynamics, leading to important feedbacks into the climate system. The use of time-series data was a valuable tool in measuring trends in post-fire vegetation across a large area and over an extended period. The final study used time-series vegetation data to measure variations in post-fire vegetation response across an extensive 2002 wildfire. Regression tree analysis related post-fire regeneration to local environmental factors such as burn severity, soil properties, vegetation, and topography. Residuals from modeled rates of post-fire regeneration were evaluated in the context of management activities and site characteristics using expert knowledge. Post-fire rates of regeneration were a function of water availability, pre-burn vegetation, and burn severity. Management activities, soil differences, and shifts in vegetation community composition resulted in deviations from the modeled post-fire regeneration rates. The results of these three research studies indicate that remotely sensed time-series vegetation data provide a useful tool for measuring post-fire vegetation dynamics. Both broad-scale and local environmental factors play important roles in defining post-fire vegetation response, and the use of remote sensing and geospatial data sets can be useful in integrating these factors and enhancing management decisions.
Download or read book Advances in Remote Sensing of Postfire Environmental Damage and Recovery Dynamics written by Alfonso Fernández-Manso and published by Mdpi AG. This book was released on 2022-10-26 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding forest fire regimes involves characterizing spatial distribution, recurrence, intensity, seasonality, size, and severity. In recent years, knowledge of damage levels can be directly related to the environmental impact of fire and, at the same time, it is a valuable estimator of fire intensity, when the data about it are not available. Remote sensing may be seen as a tool to accurately assess burn severity and to predict the potential effects of forest fires on ecosystems, thus making the prediction of the regeneration of the plant community and the effects on ecosystems easier. This information is basic to facilitate decision-making in the post-fire management of fire-prone ecosystems. Nowadays, there has been intense research activity in relation to burned areas, burn severity, and vegetation regeneration because fires in many areas of the planet are becoming more severe and extensive, and their correct evaluation and follow-up is posing great challenges to current scientists. The current advances in remote sensing and related sciences will allow us to evaluate the damage with greater precision and to know with greater reliability the dynamics of recovery. This reprint contains studies on new remote sensing technologies, new sensors, data collections, and processing methodologies that can be successfully applied in burn severity mapping, vegetation recovery monitoring, and post-fire management of fire-prone ecosystems affected by large fires. We hope this book can help readers become more familiar with this knowledge and foster an increased interest in this field.
Download or read book Permafrost Ecosystems written by Akira Osawa and published by Springer Science & Business Media. This book was released on 2010-01-04 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drawing from a decade-long collaboration between Japan and Russia, this important volume presents the first major synthesis of current knowledge on the ecophysiology of the coniferous forests growing on permafrost at high latitudes. It presents ecological data for a region long inaccessible to most scientists, and raises important questions about the global carbon balance as these systems are affected by the changing climate. Making up around 20% of the entire boreal forests of the northern hemisphere, these ‘permafrost forest ecosystems’ are subject to particular constraints in terms of temperature, nutrient availability, and root space, creating exceptional ecosystem characteristics not known elsewhere. This authoritative text explores their diversity, structure, dynamics and physiology. It provides a comparison of these forests in relation to boreal forests elsewhere, and concludes with an assessment of the potential responses of this unique biome to climate change. The book will be invaluable to advanced students and researchers interested in boreal vegetation, forest ecology, silviculture and forest soils, as well as to researchers into climate change and the global carbon balance.
Download or read book Ecological Effects of Forest Fires in the Interior of Alaska written by Harold John Lutz and published by . This book was released on 1956 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
