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Wildfires in boreal ecoregions: Evaluating the power law assumption and intra-annual and interannual variations

Lehsten, Veiko LU ; de Groot, William J.; Flannigan, Mike; George, Charles; Harmand, Peter and Balzter, Heiko (2014) In Journal of Geophysical Research - Biogeosciences 119(1). p.14-23
Abstract
Wildfires are a major driver of ecosystem development and contributor to carbon emissions in boreal forests. We analyzed the contribution of fires of different fire size classes to the total burned area and suggest a novel fire characteristic, the characteristic fire size, i.e., the fire size class with the highest contribution to the burned area, its relation to bioclimatic conditions, and intra-annual and interannual variation. We used the Canadian National Fire Database (using data from 1960 to 2010) and a novel satellite-based burned area data set (2001 to 2011). We found that the fire size distribution is best explained by a normal distribution in log space in contrast to the power law-based linear fire area relationship which has... (More)
Wildfires are a major driver of ecosystem development and contributor to carbon emissions in boreal forests. We analyzed the contribution of fires of different fire size classes to the total burned area and suggest a novel fire characteristic, the characteristic fire size, i.e., the fire size class with the highest contribution to the burned area, its relation to bioclimatic conditions, and intra-annual and interannual variation. We used the Canadian National Fire Database (using data from 1960 to 2010) and a novel satellite-based burned area data set (2001 to 2011). We found that the fire size distribution is best explained by a normal distribution in log space in contrast to the power law-based linear fire area relationship which has prevailed in the literature so far. We attribute the difference to previous studies in the scale invariance mainly to the large extent of the investigated ecoregion as well as to unequal binning or limiting the range at which the relationship is analyzed; in this way we also question the generality of the scale invariance for ecoregions even outside the boreal domain. The characteristic fire sizes and the burned area show a weak correlation, indicating different mechanisms behind each feature. Fire sizes are found to depend markedly on the ecoregion and have increased over the last five decades for Canada in total, being most pronounced in the early season. In the late season fire size and area decreased, indicating an earlier start of the fire season. Key Points <list id="jgrg20150-list-0001" list-type="bulleted"> <list-item id="jgrg20150-li-0001">Fire area-fire number relationship is analyzed for boreal wildfire globally <list-item id="jgrg20150-li-0002">The distribution does not follow a power law as previously assumed <list-item id="jgrg20150-li-0003">The fire size of Canadian wildfires increased strongly over the last decades (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
boreal wildfires, fire season, power law
in
Journal of Geophysical Research - Biogeosciences
volume
119
issue
1
pages
14 - 23
publisher
American Geophysical Union
external identifiers
  • wos:000333164700002
  • scopus:84897008925
ISSN
2169-8953
DOI
10.1002/2012JG002252
project
BECC
language
English
LU publication?
yes
id
4de135b4-d9b3-4878-9083-65f49db0189f (old id 4410814)
date added to LUP
2014-04-29 10:16:21
date last changed
2017-05-28 03:17:23
@article{4de135b4-d9b3-4878-9083-65f49db0189f,
  abstract     = {Wildfires are a major driver of ecosystem development and contributor to carbon emissions in boreal forests. We analyzed the contribution of fires of different fire size classes to the total burned area and suggest a novel fire characteristic, the characteristic fire size, i.e., the fire size class with the highest contribution to the burned area, its relation to bioclimatic conditions, and intra-annual and interannual variation. We used the Canadian National Fire Database (using data from 1960 to 2010) and a novel satellite-based burned area data set (2001 to 2011). We found that the fire size distribution is best explained by a normal distribution in log space in contrast to the power law-based linear fire area relationship which has prevailed in the literature so far. We attribute the difference to previous studies in the scale invariance mainly to the large extent of the investigated ecoregion as well as to unequal binning or limiting the range at which the relationship is analyzed; in this way we also question the generality of the scale invariance for ecoregions even outside the boreal domain. The characteristic fire sizes and the burned area show a weak correlation, indicating different mechanisms behind each feature. Fire sizes are found to depend markedly on the ecoregion and have increased over the last five decades for Canada in total, being most pronounced in the early season. In the late season fire size and area decreased, indicating an earlier start of the fire season. Key Points &lt;list id="jgrg20150-list-0001" list-type="bulleted"&gt; &lt;list-item id="jgrg20150-li-0001"&gt;Fire area-fire number relationship is analyzed for boreal wildfire globally &lt;list-item id="jgrg20150-li-0002"&gt;The distribution does not follow a power law as previously assumed &lt;list-item id="jgrg20150-li-0003"&gt;The fire size of Canadian wildfires increased strongly over the last decades},
  author       = {Lehsten, Veiko and de Groot, William J. and Flannigan, Mike and George, Charles and Harmand, Peter and Balzter, Heiko},
  issn         = {2169-8953},
  keyword      = {boreal wildfires,fire season,power law},
  language     = {eng},
  number       = {1},
  pages        = {14--23},
  publisher    = {American Geophysical Union},
  series       = {Journal of Geophysical Research - Biogeosciences},
  title        = {Wildfires in boreal ecoregions: Evaluating the power law assumption and intra-annual and interannual variations},
  url          = {http://dx.doi.org/10.1002/2012JG002252},
  volume       = {119},
  year         = {2014},
}