scholarly journals Remote sensing techniques to assess active fire characteristics and post-fire effects

2006 ◽  
Vol 15 (3) ◽  
pp. 319 ◽  
Author(s):  
Leigh B. Lentile ◽  
Zachary A. Holden ◽  
Alistair M. S. Smith ◽  
Michael J. Falkowski ◽  
Andrew T. Hudak ◽  
...  

Space and airborne sensors have been used to map area burned, assess characteristics of active fires, and characterize post-fire ecological effects. Confusion about fire intensity, fire severity, burn severity, and related terms can result in the potential misuse of the inferred information by land managers and remote sensing practitioners who require unambiguous remote sensing products for fire management. The objective of the present paper is to provide a comprehensive review of current and potential remote sensing methods used to assess fire behavior and effects and ecological responses to fire. We clarify the terminology to facilitate development and interpretation of comprehensible and defensible remote sensing products, present the potential and limitations of a variety of approaches for remotely measuring active fires and their post-fire ecological effects, and discuss challenges and future directions of fire-related remote sensing research.

Proceedings ◽  
2020 ◽  
Vol 30 (1) ◽  
pp. 78
Author(s):  
Anna Brook

Fires were once a natural phenomenon that helped to shape species distribution, contributed to the persistence of fire-dependent species, and assisted the natural evolution of ecosystems. However, nowadays, most of the forest fires worldwide are not of natural causes. Therefore, wildfires have received significant attention over the past few decades. Major ecological and policy changes were stimulated by historical frequency, extent, and severity of fires in the dry forests. These fires are important at both local to regional scales, as it might change the maintenance of landscape structure, composition, and function. Moreover, it affects pollutants, impacts air quality and raises human health risks. Many studies suggested using remote sensing data and techniques to assess fire characteristics and post-fire effects. Due to its ability to quantify patterns of variation in space and time, the remote sensing data are especially important to detect active fire extents at local and regional scales, mapping fuel loading and identify areas with long or problematic natural recovery. In the past few decades, the advantages of multi-temporal remote sensing techniques to monitor landscape change in a rapid and cost-effective manner, are reported in the scientific literature. Many studies focused on the development of techniques to evaluate and quantify fire behavior and fuel combustion. Yet the main contribution is recorded for spectral indices, e.g. the Normalized Burn Ratio (NBR), the difference in the Normalized Burn Ratio between pre- and post-fire images (dNBR), and the Normalized Difference Vegetation Index (NDVI), which are calculated by a simple combinations of different sensor bands, rely on spectral changes of the burning or burned surfaces. Numerous papers are focused on more advanced and very detailed spectral models of fuel and post-fire ash residues, mainly using laboratory spectrometers, e.g., Fourier Transform Infrared (FTIR). However, many of the developed models are not applicable in the real world. In the current talk, we will present the most recent studies and scientific activities in the field of (1) active fire detection and characterization, using mainly hyperspectral ground and airborne technologies; (2) future space-borne applications on board of nano- and micro-satellites; (3) discuss the contribution of detailed and precise spectral models for post-fire ecological effects studies; (4) describe field assessment; (5) discuss management applications and future directions of fire-related remote sensing research.


2012 ◽  
Vol 124 (1) ◽  
pp. 30
Author(s):  
Kevin G. Tolhurst

The Wombat Fire Effects Study was established to address a number of questions in relation to the effects of repeated low-intensity fires in mixed species eucalypt forest in the foothills of Victoria. This study has now been going for 25 years and has included the study of understorey plants, fuels, bats, terrestrial mammals, reptiles, invertebrates, fungi, birds, soils, tree growth, fire behaviour and weather. This forest system has shown a high resilience to fire that is attributed here to the patchiness and variability in the fire characteristics within a fire and the relatively small proportion of the landscape being affected. A means of comparing the level of “injury” caused by low-intensity prescribed fire with high intensity wildfire is proposed so that the debate about leverage benefits (the reduction in wildfire area compared to the area of planned burning) can be more rational. There are some significant implications for assessing the relative environmental impacts of wildfire compared with the planned burning program being implemented in Victoria since the Victorian Bushfires Royal Commission recommendations (Teague et al. 2010).


2010 ◽  
Vol 25 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Elizabeth D. Reinhardt ◽  
Lisa Holsinger ◽  
Robert Keane

Abstract Removal of dead and live biomass from forested stands affects subsequent fuel dynamics and fire potential. The amount of material left onsite after biomass removal operations can influence the intensity and severity of subsequent unplanned wildfires or prescribed burns. We developed a set of biomass removal treatment scenarios and simulated their effects on a number of stands that represent two major forests types of the northern Rocky Mountains: lodgepole and ponderosa pine. The Fire and Fuels Extension to the Forest Vegetation Simulator was used to simulate effects including stand development, fire behavior, and fire effects prior to the biomass removal treatment and 1, 10, 30, and 60 years after the treatment. Analysis of variance was used to determine whether these changes in fuel dynamics and fire potential differed significantly from each other. Results indicated that fire and fuel characteristics varied within and between forest types and depended on the nature of the treatment, as well as time since treatment. Biomass removal decreased fire potential in the short term, but results were mixed over the long term.


1996 ◽  
Vol 6 (4) ◽  
pp. 165 ◽  
Author(s):  
D Mckenzie ◽  
DL Peterson ◽  
E Alvarado

Models of vegetation change in response to global warming need to incorporate the effects of disturbance at broad spatial scales. Process-based predictive models, whether for fire behavior or fire effects on vegetation, assume homogeneity of crucial inputs over the spatial scale to which they are applied. Landscape disturbance models predict final burning patterns, but either do not model mechanistic behavior and explicit spread rates, or require large amounts of data to initialize simulations and predict ecological effects. Empirical data on the ecological effects of fire are not generally available at these scales, and conclusions are often extrapolated upward from stand-level data. Three methods for extrapolating ecological effects of fire across spatial scales and the sources of error associated with each were identified: (1) extrapolating fire behavior models directly to larger spatial scales; (2) integrating fire behavior and fire effects models with successional models at the stand level, then extrapolating upward; and (3) aggregating model inputs to the scale of interest. Extreme fire events present a challenging problem for modelers, regardless of which extrapolation method is employed. No single approach to modeling fire effects is inherently superior; modeling objectives and the characteristics of specific systems will determine the best strategy for each situation.


2017 ◽  
Vol 91 ◽  
pp. 845-854 ◽  
Author(s):  
Eric V. Mueller ◽  
Nicholas Skowronski ◽  
Kenneth Clark ◽  
Michael Gallagher ◽  
Robert Kremens ◽  
...  

2009 ◽  
Vol 18 (1) ◽  
pp. 116 ◽  
Author(s):  
Jon E. Keeley

Several recent papers have suggested replacing the terminology of fire intensity and fire severity. Part of the problem with fire intensity is that it is sometimes used incorrectly to describe fire effects, when in fact it is justifiably restricted to measures of energy output. Increasingly, the term has created confusion because some authors have restricted its usage to a single measure of energy output referred to as fireline intensity. This metric is most useful in understanding fire behavior in forests, but is too narrow to fully capture the multitude of ways fire energy affects ecosystems. Fire intensity represents the energy released during various phases of a fire, and different metrics such as reaction intensity, fireline intensity, temperature, heating duration and radiant energy are useful for different purposes. Fire severity, and the related term burn severity, have created considerable confusion because of recent changes in their usage. Some authors have justified this by contending that fire severity is defined broadly as ecosystem impacts from fire and thus is open to individual interpretation. However, empirical studies have defined fire severity operationally as the loss of or change in organic matter aboveground and belowground, although the precise metric varies with management needs. Confusion arises because fire or burn severity is sometimes defined so that it also includes ecosystem responses. Ecosystem responses include soil erosion, vegetation regeneration, restoration of community structure, faunal recolonization, and a plethora of related response variables. Although some ecosystem responses are correlated with measures of fire or burn severity, many important ecosystem processes have either not been demonstrated to be predicted by severity indices or have been shown in some vegetation types to be unrelated to severity. This is a critical issue because fire or burn severity are readily measurable parameters, both on the ground and with remote sensing, yet ecosystem responses are of most interest to resource managers.


2021 ◽  
Vol 13 (24) ◽  
pp. 5160
Author(s):  
Ioanna Tselka ◽  
Pavlos Krassakis ◽  
Alkiviadis Rentzelos ◽  
Nikolaos Koukouzas ◽  
Issaak Parcharidis

Earth’s ecosystems are extremely valuable to humanity, playing a key role ecologically, economically, and socially. Wildfires constitute a significant threat to the environment, especially in vulnerable ecosystems, such as those that are commonly found in the Mediterranean. Due to their strong impact on the environment, they provide a crucial factor in managing ecosystems behavior, causing dramatic modifications to land surface processes dynamics leading to land degradation. The soil erosion phenomenon downgrades soil quality in ecosystems and reduces land productivity. Thus, it is imperative to implement advanced erosion prediction models to assess fire effects on soil characteristics. This study focuses on examining the wildfire case that burned 30 km2 in Malesina of Central Greece in 2014. The added value of remote sensing today, such as the high accuracy of satellite data, has contributed to visualizing the burned area concerning the severity of the event. Additional data from local weather stations were used to quantify soil loss on a seasonal basis using RUSLE modeling before and after the wildfire. Results of this study revealed that there is a remarkable variety of high soil loss values, especially in winter periods. More particularly, there was a 30% soil loss rise one year after the wildfire, while five years after the event, an almost double reduction was observed. In specific areas with high soil erosion values, infrastructure works were carried out validating the applied methodology. The approach adopted in this study underlines the significance of using remote sensing and geoinformation techniques to assess the post-fire effects of identifying vulnerable areas based on soil erosion parameters on a local scale.


Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 65
Author(s):  
Gernot Ruecker ◽  
David Leimbach ◽  
Joachim Tiemann

Fire behavior is well described by a fire’s direction, rate of spread, and its energy release rate. Fire intensity as defined by Byram (1959) is the most commonly used term describing fire behavior in the wildfire community. It is, however, difficult to observe from space. Here, we assess fire spread and fire radiative power using infrared sensors with different spatial, spectral and temporal resolutions. The sensors used offer either high spatial resolution (Sentinel-2) for fire detection, but a low temporal resolution, moderate spatial resolution and daily observations (VIIRS), and high temporal resolution with low spatial resolution and fire radiative power retrievals (Meteosat SEVIRI). We extracted fire fronts from Sentinel-2 (using the shortwave infrared bands) and use the available fire products for S-NPP VIIRS and Meteosat SEVIRI. Rate of spread was analyzed by measuring the displacement of fire fronts between the mid-morning Sentinel-2 overpasses and the early afternoon VIIRS overpasses. We retrieved FRP from 15-min Meteosat SEVIRI observations and estimated total fire radiative energy release over the observed fire fronts. This was then converted to total fuel consumption, and, by making use of Sentinel-2-derived burned area, to fuel consumption per unit area. Using rate of spread and fuel consumption per unit area, Byram’s fire intensity could be derived. We tested this approach on a small number of fires in a frequently burning West African savanna landscape. Comparison to field experiments in the area showed similar numbers between field observations and remote-sensing-derived estimates. To the authors’ knowledge, this is the first direct estimate of Byram’s fire intensity from spaceborne remote sensing data. Shortcomings of the presented approach, foundations of an error budget, and potential further development, also considering upcoming sensor systems, are discussed.


2005 ◽  
Vol 35 (12) ◽  
pp. 2981-2995 ◽  
Author(s):  
Crystal L Raymond ◽  
David L Peterson

We had the rare opportunity to quantify the relationship between fuels and fire severity using prefire surface and canopy fuel data and fire severity data after a wildfire. The study area is a mixed-evergreen forest of southwestern Oregon with a mixed-severity fire regime. Modeled fire behavior showed that thinning reduced canopy fuels, thereby decreasing the potential for crown fire spread. The potential for crown fire initiation remained fairly constant despite reductions in ladder fuels, because thinning increased surface fuels, which contributed to greater surface fire intensity. Thinning followed by underburning reduced canopy, ladder, and surface fuels, thereby decreasing surface fire intensity and crown fire potential. However, crown fire is not a prerequisite for high fire severity; damage to and mortality of overstory trees in the wildfire were extensive despite the absence of crown fire. Mortality was most severe in thinned treatments (80%–100%), moderate in untreated stands (53%–54%), and least severe in the thinned and underburned treatment (5%). Thinned treatments had higher fine-fuel loading and more extensive crown scorch, suggesting that greater consumption of fine fuels contributed to higher tree mortality. Fuel treatments intended to minimize tree mortality will be most effective if both ladder and surface fuels are treated.


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