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Human–environmental drivers and impacts of the globally extreme 2017 Chilean fires

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Abstract

In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000 km2, an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979-2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons.
RESEARCH ARTICLE
Human–environmental drivers and impacts of the globally
extreme 2017 Chilean fires
David M. J. S. Bowman , Andre
´s Moreira-Mun
˜oz, Crystal A. Kolden,
Roberto O. Cha
´vez, Ariel A. Mun
˜oz, Fernanda Salinas,
A
´lvaro Gonza
´lez-Reyes, Ronald Rocco, Francisco de la Barrera,
Grant J. Williamson, Nicola
´s Borchers, Luis A. Cifuentes,
John T. Abatzoglou, Fay H. Johnston
Received: 11 April 2018 / Revised: 23 July 2018 / Accepted: 25 July 2018
Abstract In January 2017, hundreds of fires in
Mediterranean Chile burnt more than 5000 km
2
, an area
nearly 14 times the 40-year mean. We contextualize these
fires in terms of estimates of global fire intensity using
MODIS satellite record, and provide an overview of the
climatic factors and recent changes in land use that led to
the active fire season and estimate the impact of fire
emissions to human health. The primary fire activity in late
January coincided with extreme fire weather conditions
including all-time (1979–2017) daily records for the Fire
Weather Index (FWI) and maximum temperature,
producing some of the most energetically intense fire
events on Earth in the last 15-years. Fire activity was
further enabled by a warm moist growing season in 2016
that interrupted an intense drought that started in 2010. The
land cover in this region had been extensively modified,
with less than 20% of the original native vegetation
remaining, and extensive plantations of highly flammable
exotic Pinus and Eucalyptus species established since the
1970s. These plantations were disproportionally burnt
(44% of the burned area) in 2017, and associated with
the highest fire severities, as part of an increasing trend of
fire extent in plantations over the past three decades.
Smoke from the fires exposed over 9.5 million people to
increased concentrations of particulate air pollution,
causing an estimated 76 premature deaths and 209
additional admissions to hospital for respiratory and
cardiovascular conditions. This study highlights that
Mediterranean biogeographic regions with expansive
Pinus and Eucalyptus plantations and associated rural
depopulation are vulnerable to intense wildfires with wide
ranging social, economic, and environmental impacts,
which are likely to become more frequent due to longer
and more extreme wildfire seasons.
Keywords Fire weather Forest plantations
Land cover change Mediterranean climate
Smoke pollution Wildfire
INTRODUCTION
Wildfires are increasingly recognized as a natural hazard
that can cause significant social, economic, and environ-
mental harms. Settlement patterns and land management
actions affect the magnitude of wildfire impacts, which are
showing signs of being exacerbated by anthropogenic
global climate change. Analysis of global meteorological
data shows that wildfire seasons are becoming longer and
characterized by more extreme fire weather (Jolly et al.
2015). Some studies have demonstrated that anthropogenic
climate change has contributed to increased vegetation
dryness, longer fire seasons, and increased incidence of
extreme fire danger in parts of the globe (Abatzoglou and
Williams 2016). Globe-scale satellite analyses have also
shown that extremely energetic and destructive fire events
have been linked to extreme fire weather conditions and
promoting economically disastrous fire (Bowman et al.
2017).
Partitioning the relative effects of inherent ecology,
human actions, and climate change is difficult. Wildfire is
not exclusively a climate phenomenon; it has biological
and human dimensions. Some plants and vegetation types
(e.g., tall grasses, Eucalyptus) are inherently more flam-
mable than others and human ignitions, fire suppression,
and land uses (e.g., plantations, urbanization) affect the
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s13280-018-1084-1) contains supple-
mentary material, which is available to authorized users.
ÓRoyal Swedish Academy of Sciences 2018
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https://doi.org/10.1007/s13280-018-1084-1
likelihood of fires by altering patterns of landscape fire
hazard (Bowman et al. 2011). Collectively, the spatial
occurrence and extent, behavior (intensity and rate of
spread), and biological impacts are the result of a complex
amalgam of climatic, biological, and human influences.
Nonetheless, humans can profoundly positively and nega-
tively influence fire activity. For instance, the Maori col-
onization of New Zealand resulted in a dramatic increase in
fires (McWethy et al. 2010); by contrast, in the western
USA there has been an effective program of fire suppres-
sion since the beginning of the 20th century (Marlon et al.
2012). Given the complex direct and indirect drivers of fire
activity, it is crucial to consider the respective roles of
climate, biogeography, land use, and fire management in
affecting fire activity, which necessarily demands a trans-
disciplinary approach and analysis of specific fire events.
In this context, we consider a major fire event that
occurred in the austral summer of 2016/17 in Central Chile
(32–38°S, 70–73°W), a densely populated region with a
Mediterranean climate. Between January 1 and February
10, 2017, large areas of Central Chile were affected by
historically unprecedented wildfires that have collectively
become known as ‘tormenta de fuego’ (in English, ‘the fire
storm’). Hundreds of individual fires burned more than
5000 km
2
, threatening densely populated areas and
destroying extensive forestry plantations, small agricultural
holdings, and several rural villages, with 11 confirmed
fatalities. Although this fire event was widely reported in
the media and has been the subject of brief commentaries
in global scientific literature considering the ecological
consequences (Martinez-Harms et al. 2017), policy
dimensions (Go
´mez-Gonza
´lez et al. 2018), and possible
linkages with climate change (Anonymous 2017; Holz
et al. 2017), there are yet no detailed pyrogeographic
analyses that holistically consider the biophysical aspects
of the fires and the health impacts of the smoke.
Rigorous post-mortem analysis of significant fire events
is crucial to provide insight on key ingredients that con-
tributed to fire risk, occurrence, and growth rates and the
identification of a host of potential drivers. We acknowl-
edge that such a case study approach is necessarily
opportunistic, and constrained by available, and often
imperfect, data from a variety of sources. Here we (a) use
historical records to contextualize the extent of the fires and
their association with different land cover types, (b) assess
the severity of the fires at a regional and global scale using
satellite imagery analysis, (c) identify climatic trends and
meteorological conditions that preceded and occurred
during the fire, and (d) make a first approximation of the
magnitude of the health impacts of the smoke generated
from this event. Finally, we discuss both the value of the
transdisciplinary case study approach taken here, and
canvas the broad implications of this fire event for other
landscapes with Mediterranean climates.
MATERIALS AND METHODS
Fire severity and extent
We determined interannual variability of the area burned
and number of ignitions for five administrative regions of
central Chile from 1985–2017 to contextualize the
2016-2017 fire season. Fire data (burned area and ignitions)
were acquired from Corporacio
´n Nacional Forestal online
data (CONAF 2017). We compared burned area in Pinus
and Eucalyptus plantations with non-plantation areas
(comprised grasslands, shrublands, and woodlands) for
each fire year (July - June) from 1984/85 through 2015/16.
We conducted a spatial overlay analysis from the 2017 fire
perimeters reported by Corporacio
´n Nacional Forestal
(CONAF 2017) with land cover from Zhao et al. (2016)to
quantify the relative proportions of land cover type burnt
and determine if these proportions were greater than
expected. We applied a Chi-Square test to determine if the
area of plantations burnt was significantly greater than
expected.
To quantify wildfire effects on vegetation productivity,
we mapped contemporaneous biomass loss as quantified by
the 16-day Enhanced Vegetation Index (EVI) product
(MOD13Q1) from MODIS (Huete et al. 2010). Data were
pre-processed using the quality assessment bands, and by
eliminating pixels corresponding to snow, water, clouds,
cloud-shadows, and high level of aerosols. For each pixel
in central Chile, we calculated an anomaly for the wildfire
season by first developing a probability curve of a given
EVI value occurring on a given day during the primary
growing season from the first 16 years of the EVI data (i.e.,
excluding the 2016–2017 growing season). We then cal-
culated the cumulative anomaly (difference between
baseline and post-fire EVI values) for a given pixel for the
2016–2017 growing season up to January 1, the final EVI
scene before the wildfires began, to account for pre-fire
impacts of the severe drought and heat on vegetation.
Finally, we calculated the fire-induced EVI anomaly as the
difference between the EVI observed on March 6, 2017
(the start of post-fire recovery) and the expected (modeled)
EVI, minus the 2016–2017 growing season anomaly up to
January 1. These phenological reconstructions and anom-
aly calculations were performed using the software R and
the package npphen (Cha
´vez et al. 2017). We then ran-
domly sampled 10,000 points from within the burnt areas
and attributed both pre-fire land cover and post-fire EVI
anomaly for each point. A Kolmogorov–Smirnov test
(Lilliefors 1967) was applied to the EVI anomaly
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distributions to test for significant differences in the dis-
tribution of biomass loss between plantation and non-
plantation sites (Parks et al. 2014). To assess the fires by
intensity against the MODIS-derived global extreme
events, we used the database developed by Bowman et al.
(2017), we updated this database through April 30, 2017,
and then re-ranked the events based on the new years of
data.
Climatic context and fire weather conditions
To assess meteorological conditions during the fire event
and the climatic context for the fires, we acquired daily
data output from the ERA-Interim reanalysis at a 0.75°
spatial resolution from 1979 to 2017. Daily precipitation
data from the Multi-Source Weighted-Ensemble Precipi-
tation (MSWEP) product (Beck et al. 2017) at 0.5°spatial
resolution were prioritized over ERA-Interim precipitation
given its incorporation of gauge-based precipitation data.
Daily accumulation precipitation from MSWEP was
interpolated to the ERA-Interim grid for compatibility
following Abatzoglou et al. (2018). These data were used
to compute a suite of bioclimatic variables that have been
linked to wildfire activity in global studies including vapor
pressure deficit (VPD), climate water balance, and the Fire
Weather Index (FWI) from the Canadian Forest Fire
Danger Rating System (van Wagner 1987).
All calculations were performed at the native resolution
of the data and then aggregated to cover the geographic
extent of central Chile excluding non-land pixels. Daily
mean wind speed, maximum temperature, and FWI were
examined for Austral summer (DJF) 2016–2017. In addi-
tion to examining daily near-surface fire weather data for
December 2016–February 2017, we computed climato-
logical statistics to contextualize conditions. This was done
by calculating the median, interquartile range, and 95th
percentile range of daily data using a 21-day-centered
moving window of historical daily data from 1979-2016.
Finally, to provide longer-term context for drought condi-
tions across the region leading up to the fire event, we
acquired gridded monthly self-calibrated Palmer Drought
Severity (sc-PDSI) indices from the Climatic Research
Unit dataset for the study region (Osborn et al. 2017).
Whereas we make no attempt to explicitly model burned
area extent during the 2017 firestorm, we provide a cli-
matic context for the event by calculating linear climate-
burned area correlations for the study area excluding the
2017 fire season. This was done separately for the base-10
logarithm of fire season (Dec-Mar) burned area, as well as
for burned area in plantation and non-plantation areas. We
considered interannual correlations to climate variables
concurrent to the core fire season (e.g., temperature, VPD,
occurrence of extreme fire danger days defined as FWI
exceeding the 95th percentile) as well as precipitation
antecedent to the fire season-given relationships reported in
prior studies (e.g., Urrutia-Jalabert et al. 2018).
Air quality and health impacts
We followed the approach of Broome et al. (2016), who
evaluated a period of severe pollution from landscape
burning in Sydney, Australia. The details of this analysis are
provided in the electronic supplementary material. We
obtained hourly measurements of particulate matter less
than 2.5 micrometers in diameter (PM
2.5
) per cubic meter of
air from the Chilean National Air Quality Information
System (Sistema de Informacio
´n Nacional de Calidad del
Aire (SINCA) 2017) (Table S1). We included all monitors
in regions affected by the fire as follows: Valparaiso,
Metropolitan, O’Higgins, Maule, and Biobio. The differ-
ence between the historical mean PM
2.5
for January and
February 2012–2016, and the measured PM
2.5
during the
fire period was calculated to estimate the excess pollution
attributable to the fires. Mortality and hospital discharge
records for 2011–2015 were obtained from the Department
of Statistics and Health Information of the Ministry of
Health (Departamento de Informacio
´n y Estadı
´sticas de
Salud Ministerio de Salud (DEIS) 2017) and population
data from the 2017 National Census (Instituto Nacional de
Estadı
´stica (INE) 2017) (Table S2). We calculated the
baseline average daily incidence of all-cause mortality, and
hospital admissions for respiratory and cardiovascular
conditions during the summer months of January and
February by region (Table S2). We then applied standard
concentration–response functions for PM
2.5
developed by
the World Health Organization (WHO 2013), to estimate
the number and 95% confidence intervals (95% CI) of
premature deaths, respiratory, and cardiovascular hospital
admissions attributable to increased PM
2.5
from the fires
(Table S3).
RESULTS
The ‘tormenta de fuego’ event involved hundreds of fires
that burned a total of 5132 sq. km (Fig. 1). The extent of
these fires was 5.7 times the area burned in the next largest
fire year on record (1998–1999) and 13.6 times the 32-year
mean (excluding the 2016–2017 fire season) for the five
administrative regions comprising central Chile (Fig. 1).
This extreme anomaly, however, occurred despite a normal
number of documented ignitions (CONAF 2017) (Fig. 1).
The predominant vegetation types burnt were Pinus (31%)
and Eucalyptus (12%) plantations and grass/shrub range-
lands (44%), with a substantially smaller proportion (11%)
of natural forests (Fig. 2). As plantations only comprise
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14% of the landscape of central Chile, the fires burned at a
significantly higher rate than expected in this human-
engineered land cover type (d.f.=1, p\0.0001). The
disproportionate amount of fire in plantations in 2016–17 is
consistent with a significant increase in plantation burned
area over the 33-year record. For example, approximately
40% of the burned area from fire seasons 2005/06 to
2016/17 occurred in plantations compared to 21% of the
burned area for fire seasons from 1984/85 to 2004/05.
Plantations also burned more severely than non-planta-
tion land cover types with greater loss of biomass (Fig. 2).
The median EVI negative anomaly (i.e., departure from
normal vegetative greenness) for plantations was 0.19,
compared to a median negative anomaly of 0.14 for other
land cover types, where the range of values for all points
was 0.07 (lowest severity) to 0.38 (highest severity). While
other land cover types displayed a near-normal distribution
of EVI anomaly as a proxy for burn severity, the EVI
distribution for plantations was skewed towards more
severe (Fig. 3). The K–S test confirmed that fire effects in
plantations were significantly more severe than in other
land cover types (a\0.0001).
During the fires, daily regional FWI was high with
several days above the 95% distribution (including the all-
time highest value in the 1979–2017 period on 25 January)
that were coincident with the largest growth rate of
reported fires (Fig. 4). High daily maximum temperatures
contributed to extreme fire weather (Fig. 4). During the
latter half of January 2017, 7 days fell above the 95%
distribution, including the warmest region-wide daily mean
Fig. 1 Trends in area burned (broken down by plantation and non-
plantation land cover types) and number of ignitions for five regions
in central Chile from Corporacio
´n National Forestal (CONAF 2017)
that show a [500% increase in area burnt in the 2017 event despite a
typical number of ignitions. Over the 33-year period—475,000 of
plantations burned, and excluding 2017 at total of 12,000 ha was
burned
Fig. 2 Land cover from Zhao et al. (2016) and 2017 fire perimeters from CONAF (2017) demonstrating that the fires were concentrated in
plantations (left panel). Proportion of burned area versus proportion of central Chile landscape for each land cover type demonstrating expected
versus observed proportions for each class (right panel)
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temperature in the ERA-Interim record (1979–2017) and
all-time maximum temperatures records set at the two
long-term stations in the region: Arturo Merino Benitez
International (Station CIM00085574) and Carriel Sur
International (Station CIM00085682). Region-wide winds
speeds were also above average for the latter half of Jan-
uary 2017, punctuated by a couple of days where winds
where above the 95% distribution contributing to fire
spread. While summer average temperatures were well
above normal, as defined by 1981–2010 averages, summer
mean drought stress as realized through VPD was only
slightly above average (Fig. 5). The wet warm season and
cool season (1-year lag) preceding the fire year moderated
the effects of a significant prolonged and historically sig-
nificant drought from 2008–2015 (sc-PDSI \-1.5). Cli-
mate–fire relationships excluding the 2016–2017 fire
season showed significant positive correlations between
burned area extent and summer temperature, VPD, and the
number of days with extreme FWI, most notable for burned
area in plantations (Table 1). Likewise, burned area extent
was weakly negatively correlated to cumulative precipita-
tion the previous winter, but positively correlated to pre-
cipitation in the preceding year, suggestive that interannual
variability in both fuel abundance and fuel dryness enable
fire activity in the region.
Fig. 3 Map of Enhanced Vegetation Index (EVI) anomaly in central
Chile in early 2017 shows where the greatest loss of vegetation
occurred relative to expected greenness, due to the wildfires (top
panel). Distribution of EVI anomaly values for 10,000 randomly
sampled pixels within burnt areas, stratified by whether land cover
type was plantation or not, with 95% CI envelope (bottom panel)
Fig. 4 Daily amaximum temperature, bmean wind speed, and
cFire Weather Index from December 1, 2016–February 28, 2017
averaged over central Chile. The light and dark gray depict 21-day
moving averages of the interquartile range (IQR) and the middle 95%
of the data for the period of record (1979–2017), while the bold black
line shows the average daily data from 1981–2010
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Reanalysis of the global extreme wildfire events data-
base of Bowman et al. (2017), based on daily Fire Radia-
tive Power (RFRP) from the MODIS space-borne sensor
summed over 100 km
2
, highlighted the extreme nature of
this fire event globally. A total of 11 of the revised top 500
RFRP events (out of a total of more than 30.4 million
events in the 2002–2017 MODIS record) occurred in
central Chile between 18 and 26 of January 2017, corre-
sponding with the peak in fire activity and extreme fire
weather conditions (Fig. 6).
Smoke impacts varied by region (Table S4). The highest
daily average PM
2.5
recorded during the fire period was
739 lg/m
3
in the region of Biobio, while in the
Metropolitan region, which includes the capital city of
Santiago, the peak PM
2.5
was 93 lg/m
3
at Independencia.
More than 9.5 million people, representing approximately
54% of the total population of Chile (17.5 million), were
exposed to an average increase in PM
2.5
of 26.8 lg/m
3
above historical mean concentrations for a period of
16 days (Fig. 7). The calculated health impacts of the
increased air pollution were (N, 95% Confidence interval):
76 (24–132) premature deaths 140 (0–343) respiratory
hospital admissions and 69 (15–127) cardiovascular hos-
pital admissions (Table S5).
DISCUSSION
We have shown that the fires that occurred in central Chile
in the January 2017 were some of the most intense land-
scape fires on Earth in this century. Our synthesis of
available biophysical information leads us to conclude that
area burned (albeit not number of fires) was historically
anomalous, driven by extreme climatic conditions. Further,
we find that extensive monocultures of highly flammable
Pinus and Eucalyptus plantations played a substantial role
in these extreme fires.
We acknowledge this study is necessarily opportunistic
working with the imperfect data, which is an
inevitable consequence of investigating an unpre-
dictable event. Although uncommon in environmental
sciences, case study approaches are recognized of being of
great value in progressing understanding of many fields,
such as medicine, astronomy, meteorology, and volcanol-
ogy, where experimentation is ethically or practically
impossible and important phenomenon occur
Fig. 5 Time series of aDecember–February mean temperature,
bDecember–February vapor pressure deficit (VPD), ccumulative
precipitation for the warm season (Oct–Apr) and cool season (May–
Sep), and dApril self-calibrated Palmer Drought Severity Index for
central Chile. The horizontal dashed lines depict the 1981–2010
averages in (ac)
Table 1 Pearson’s correlation coefficients between the base-10
logarithm of fire season (Dec–Mar) burned area in central Chile and
climate variables both concurrent to and antecedent to the fire season.
Correlations were computed over a 32-year period from the fire
season 1984/85 to 2015/16. Statistically significant correlations at
p\0.05 are shown in bold. All climate data were aggregated over
land covering 32–38°S, 70–72.5°W
Variable All
fire
Plantation Non-
plantation
Mean temperature (Dec–Feb, DJF) 0.32 0.45 0.22
Precipitation (DJF) -0.09 -0.03 -0.16
Vapor pressure deficit (DJF) 0.37 0.43 0.36
Days where the Fire Weather
Index [95th percentile (DJF)
0.39 0.47 0.36
Self-calibrated Palmer Drought
Severity Index (DJF)
-0.26 -0.34 -0.22
Precipitation (previous wet season,
May–Sep)
-0.31 -0.30 -0.30
Precipitation (previous warm season,
Oct–Apr, lag -1)
0.46 0.39 0.46
Precipitation (previous wet season,
May–Sep, lag -1)
0.41 0.41 0.35
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unpredictably. There is growing awareness that the syn-
thesis of data to understand extreme fire events is pivotal.
Indeed, a recent editorial in Nature Climate Change stated
‘Earth-monitoring efforts as well as on the ground research
seem to be ever more valuable resources as we try to
manage the direct and indirect risks that changing wildfires
pose to people and the environment’ (Anonymous 2017).
Below we consider broader implication of our case study
for flammable Mediterranean landscapes globally.
The large area burnt, and the extremely intense fires
detected by the MODIS satellite, in central Chile, was
associated the anomalous meteorological conditions
including highest temperatures and FWI in the 39-year
reanalysis record. Although meteorological records did not
identify particularly windy conditions, the rapid rate of
spread, erratic behavior change, and sustained nocturnal
intensity reported by fire fighters suggest that the fires were
likely creating their own localized wind fields. Addition-
ally, climate variability leading up to the 2016–2017 fire
season appears to also have contributed to the high inten-
sity of the fires. Mediterranean climates, including the
central Chilean coast plains and ranges, are particularly
conducive to wildfires given cool wet winters that favor
fuel production and hot dry summers that provide reliable
Fig. 6 Location of pixels ranking in the revised top 500 most extreme global fire events (as defined by MODIS-derived RFRP 100 km
-2
).
Squares indicate the location, date, and rank (#/500) from 2002 to May 2017 following the methods of Bowman et al. (Bowman et al. 2017),
demonstrating that 11 (2%) of the top 500 events occurred in the 2017 fires
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fire weather (Cowling et al. 1996, Keeley 2012). Our
results, and the results of others (Urrutia-Jalabert et al.
2018; Abatzoglou et al. 2018), suggest that interannual fire
activity in central Chile significantly correlates with sum-
mer water deficit, and precipitation that occurred in the
previous growing season (Table 1). Such antecedent sea-
sonal effects are well-understood features of the pyro-
geography of seasonal environments (Bradstock 2010).
Climate variability leading up to the fire season included
an antecedent moist growing season associated with El Nin
˜o
conditions in 2015/16 that result in increased biomass pro-
duction and hence available fuel. Historical studies have
related fire activity in southern South America has also been
to the positive phase of the Southern Annular Mode (SAM)
due to warmer and drier conditions (Holz et al. 2017; Urrutia-
Jalabert et al. 2018), as was the case before the fires. Addi-
tionally, the fires occurred after the 2010-2016 drought,
which was one of the most extreme droughts in the last
millennium (Garreaud et al. 2017). There is evidence that
frequency of droughts has been increasing since 1950
(Gonza
´lez-Reyes 2016; Gonza
´lez-Reyes et al. 2017), pos-
sibly in response to climate change (Boisier et al. 2016). In
addition, future projections show a decline of precipitation
rate in 40% of the total annual amounts over Central Chile for
the 21st century (Comisio
´n Nacional del Medio Ambiente
(CONAMA) 2006), increasing the severity and frequency of
droughts events (Bozkurt et al. 2017). Despite the primacy of
climatic conditions in driving the fire intensity and extent of
the fires, our study highlights the need to consider additional
factors such as land use and vegetation type.
Natural vegetation in Mediterranean regions has adapted
to a strongly seasonal climate with a recovery mechanism
to both drought and fire disturbance (Cowling et al. 1996;
Keeley 2012). However, unlike other Mediterranean
regions, natural (lightning) ignitions are rare in Mediter-
ranean Chile. Even though plant species in the Nothofagus
forests, Acacia caven and Prosopis chilensis savannas, and
sclerophyllous shrublands that characterize central Chile
can recover from fire damage via basal and aerial
resprouting and soil seed banks, the natural flora is less
adapted to fire than other climatically similar regions
(Montenegro et al. 2003). This is clearly apparent by the
sharply contrasting recovery of burnt Eucalyptus trees to
native trees (Fig. 8).
Colonization by indigenous people in the early Holo-
cene and European colonization since the 16th century
resulted in marked increase in landscape fire and caused a
loss of fire-sensitive vegetation (Aravena et al. 2003). In
the mid-20th century, much natural vegetation in Central
Chile had been converted to small-scale agricultural
enterprises (Aronson et al. 1998). Since the 1970s, a
massive program of Pinus radiata and Eucalyptus globulus
Fig. 7 Air quality impacts from the 2017 fire event in central Chile both temporally (a) and spatially (b). Aggregated across the five regions of
central Chile, residents were exposed to poor air quality exceeding the WHO (2017) limit of 25 lg/m
3
fine particulate matter (PM
2.5
) for a total of
15 days between 18 January and 2 February (a), corresponding with the peak of fire consumption (i.e., area burnt) across the region but also
resulting in delayed atmospheric clearing after the peak burning period. Over 9.5 million residents were impacted across the fire regions (b), most
of them in the metropolitan capital region surrounding the capital city of Santiago
123 ÓRoyal Swedish Academy of Sciences 2018
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plantations has been implemented (Aronson et al. 1998;
Klubock 2006; Heilmayr et al. 2016). We found a strong
association with area burnt and fire severity with Pinus and
Eucalyptus plantations. Plantations are particularly flam-
mable because of closely dense trees and deep litter beds,
which result in sharply increased landscape flammability
and, hence the need for fire suppression (Pen
˜a-Ferna
´ndez
and Valenzuela-Palma 2005; Carmona et al. 2012; Diaz-
Hormazabal and Gonzalez 2016;U
´beda and Sarricolea
2016). Densely stocked regenerating stands of Eucalyptus
are known to favor high severity fires (Taylor et al. 2014;
Bowman et al. 2016). Unlike native vegetation where fire
risk increases after periods of above annual rainfall due
fuels build up, monocultures of exotic trees are likely to
become highly flammable during anomalously dry seasons
such as the 2015/16 summer due to leaf shedding and
desiccation of fine fuel. Anticipating increasing fire risk
due to climate change, Go
´mez-Gonza
´lez et al. (2018) stress
the need for fuel management in Pinus and Eucalyptus
plantations to reduce fire hazard.
The fire hazard of the plantations is further increased
because of a socio-ecological consequence of industrial-
scale forestry plantations that lead to widespread rural
depopulation and loss of small-scale traditional agricultural
enterprises run by poor rural landowners (campesinos)
(Pen
˜a-Ferna
´ndez and Valenzuela-Palma 2005; Klubock
2006). For example, Curepto commune in Maule region,
lost 25% of its population between 1974 and 2015, due to
the expansion of forest industry (Aguilera Vivanco 2016).
This sociological change has reduced landscape complex-
ity thereby making flammable fuels more continuous.
Further, political opposition to industrialized forestry in
some regions has been linked to the destruction of plan-
tations by arson (U
´beda and Sarricolea 2016).
Quantification of the direct and indirect economic
impacts of the fires, and the insured and uninsured losses, is
beyond the scope of this paper, but is likely to be sub-
stantial because of the extensive loss of homes (such as the
entire Santa Olga village), structures, and damaged large-
scale agricultural enterprises such as vineyards and small-
scale rural holdings (Fig. 8). The loss of plantations will
also have enduring negative economic impacts to the
Chilean economy through the destruction of timber
resources given the forest industry contributes US$2.8
trillion to the national economy annually, and employs
1.5% of jobs nationwide (Instituto Forestal (INFOR) 2016).
Fig. 8 High mortality induced by extreme fire behavior in Nothofagus forest [DMJS Bowman] (a); aerial view of the complete destruction of
the village of Santa Olga in the Maule region [permission Ministerio de Bienes Nacionales] (b); fire effects due to high intensity fire behavior,
including rock shattering, whole plant consumption, and hydrophobic soils facilitating erosion [A. Moreira-Mun
˜oz] (c), and high burn severity in
Pinus radiata plantation [DMJS Bowman] (d)
ÓRoyal Swedish Academy of Sciences 2018
www.kva.se/en 123
Ambio
Central Chile is a biodiversity hotspot where nearly all the
remaining natural vegetation is on private lands (Pliscoff
and Fuentes-Castillo 2011). There is concern that there is
little incentive to restore privately owned natural vegeta-
tion (Martinez-Harms et al. 2017). Ecosystem services are
likely to be severely degraded by the fires due to extensive
soil erosion on steep slopes, loss of carbon storage,
reduction of biodiversity, and smoke pollution, although
there is as yet little quantification of these effects (Fig. 8).
It has been estimated that the total emission of the fires was
about 30 megatonnes CO
2
, which would have accounted
for ‘approximately 8% of the January 2017 total global fire
emissions’ (Parrington et al. 2017). Our results show that
smoke from these fires caused episodes of extremely poor
air quality and haze affecting the most densely populated
region of Chile and thus about half of the nation’s popu-
lation. Our health assessment suggests that smoke killed
seven times as many people as the actual inferno. The link
between wildfire smoke exposure and poor health is well
established; population exposure to wildfire smoke has
been associated with increased mortality, hospital admis-
sions, symptoms, and medication use, especially in people
with chronic lung diseases (Reid et al. 2016). Our health
impact assessment highlighted the large health burden from
wildfire smoke when large populations are affected. There
is acknowledged uncertainty around the estimates. How-
ever, in available studies, the associations between partic-
ulate matter and health outcomes in Chile have shown
broadly similar effect size estimates to those used in this
assessment (Cifuentes et al. 2000; Sanhueza et al. 2009).
The 2017 Chilean ‘tormenta de fuego’ event raises
concern about the fire risk of similar catastrophic fire in
Mediterranean climate zones. Historically wildfire disasters
are concentrated in southern Australia and western North
America (Moritz et al. 2014; Bowman et al. 2017), with
fewer events in the climatically similar Mediterranean
Basin due to high human population densities and different
land uses (Bowman et al. 2017). However, socio-ecological
trends of rural depopulation and widespread Pinus and
Eucalyptus plantations, combined with a rapidly changing
climate, apparently contribute to an increase of fire disas-
ters in southern Europe (Moreira et al. 2011; Pausas and
Ferna
´ndez-Mun
˜oz 2012; Nunes et al. 2016; Oliveira et al.
2017;Go
´mez-Gonza
´lez et al. 2018). This problem was
well illustrated by extreme wildfires in Mediterranean
Europe during the 2017 boreal summer that caused fatali-
ties and widespread loss of property in Spain and Portugal
(Boer et al. 2018;Go
´mez-Gonza
´lez et al. 2018) and those
in California in late 2017 (Nauslar et al. 2018).
Our findings have substantial implications for under-
standing the interplay between climate and land cover
change on fire activity, and the likely consequences for fire
activity in other flammable landscapes in a warming world.
The Chilean fires were extremely difficult to control
despite using a well-developed fire suppression force
including ground crews (professional fire fighters and local
community) and aerial water bombing (including the
Boeing 747 Supertanker, the world’s biggest aerial fire
bomber, which was partially funded by foreign private
donors), but little vegetation reduction had occurred locally
as a proactive measure to reduce fire hazard. This under-
scores the urgent need for developing sustainable socio-
ecological systems for management of flammable land-
scapes where the risks of extreme fires are being amplified
by climate change (Moreira et al. 2011; Fernandes 2013;
Moritz et al. 2014; Fischer et al. 2016; Nunes et al. 2016,
U
´beda and Sarricolea 2016; Bowman et al. 2017). In
Portugal, landscape analysis has shown that having a mix
of agriculture, forestry, and grazing can reduce the occur-
rence and impact of wildfires (Nunes et al. 2016). Small-
scale clearing around structures can also reduce the
destructive effects of fire. Under catastrophic fire weather
conditions in both Australia and US Mediterranean
ecosystems, the probability of houses burning has been
reduced where trees and shrubs are removed within 30–40
m of houses (Gibbons et al. 2012; Syphard et al. 2014). It is
possible, therefore, that improved landscape planning and
design in Mediterranean landscapes can reduce fire hazard
(Moreira et al. 2011), including creating mosaics of flam-
mable and less flammable vegetation, planting orchards
and vineyards, with an associated increased labor force in
flammable landscapes (Otero 2016). It must be acknowl-
edged that sustainably funding such initiatives is more
difficult than investing in classical fire-fighting approaches;
indeed, there remains unresolved tension between the roles
of government and industry (top down) and local com-
munity (bottom up) in managing fuels and ignitions
(Moreira et al. 2011; Fernandes 2013; Fischer et al. 2016).
CONCLUSION
We show that the 2017 Chilean fires were globally extreme
and historically anomalous. The fires were associated with
fire weather conditions unprecedented in the last four
decades and an antecedent severe multiannual drought.
Further, the establishment of extensive highly flammable
Pinus and Eucalyptus plantations disrupted a form of tra-
ditional Mediterranean silvopasture and led to rural
depopulation. The fires had substantial effects on air
quality and human health, released globally significant
amounts of CO
2
, and impacted a global biodiversity hot-
spot. The 2017 Chilean fires highlight the vulnerability of
this and other Mediterranean settings that are affected by
similar land cover and demographic changes, and are prone
to experience more extreme fires under anthropogenic
123 ÓRoyal Swedish Academy of Sciences 2018
www.kva.se/en
Ambio
climate change. This study highlights the joint effects of
climate extremes and land-use practices in contributing to
catastrophic wildfires.
Acknowledgements This paper is based on a workshop led by AM-
M, that Pia Osses and the Biogeography course 2017 helped organize.
DMJSB and AM-M led the writing of the paper with input from all
authors as follows: CAK finalized the figures; GJW and CAK
undertook the FRP analysis; ROC and RR did the EVI anomalies and
burn severity analysis and figures; AM and AG-R did the PDSI
drought analysis and figures; JTA provided analysis of the fire cli-
matology; FHJ, NB, LAC, and FDLB undertook the analysis of PM
2.5
pollution and health impacts; FS evaluated the ecological impacts of
the fires. This paper is the output of a symposium ‘Chile en Llamas’
held in May 2017 by Instituto de Geografı
´a, Pontificia Universidad
Cato
´lica de Valparaı
´so, Chile. The work was supported by the fol-
lowing grants: Direccio
´n General de Vinculacio
´n con el Medio
PUCV, Fondecyt Iniciacio
´n No. 1150422, and 11161061; Fondecyt
Regular No.1150425 Centro de Ciencia del Clima y la Resiliencia
(CR)2; Fondap No. 15110009; CONICYT PAI No. 82140001; Fon-
decyt Iniciacio
´n No. 11171041; and Australian Research Council
Linkage Grant LP130100146.
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AUTHOR BIOGRAPHIES
David M. J. S. Bowman (&) is a Research Professor in the School of
Natural Sciences at the University of Tasmania. He is a pyrogeog-
rapher researching the socio-ecological dimensions of wildland fire at
multiple spatio-temporal scales.
Address: School of Natural Sciences, University of Tasmania, Private
Bag 55, Hobart, TAS 7001, Australia.
e-mail: david.bowman@utas.edu.au
Andre
´s Moreira-Mun
˜oz is a Full Professor at the Instituto de Geo-
grafı
´a, Pontificia Universidad Cato
´lica de Valparaı
´so. He is a bio-
geographer interested in biodiversity conservation and the processes
that threaten ecosystems, like urban sprawl and wildland fires.
Address: Instituto de Geografı
´a, Pontificia Universidad Cato
´lica de
Valparaı
´so, Av. Brasil 2241 Valparaı
´so, Chile.
e-mail: andres.moreira@pucv.cl
Crystal A. Kolden is an Associate Professor at the College of Natural
Resources, University of Idaho. Her research interests include pyro-
geography and geospatial analysis of socio-ecological systems.
Address: College of Natural Resources, University of Idaho, Moscow,
ID 83844-1133, USA.
e-mail: ckolden@uidaho.edu
Roberto O. Cha
´vez is an Associate Professor at the Instituto de
Geografı
´a and chair of the Lab. of Geo-information and Remote
Sensing, Pontificia Universidad Cato
´lica de Valparaı
´so. His research
interests include land surface phenology, remote sensing time series
analysis, and environmental impact assessment.
Address: Instituto de Geografı
´a, Pontificia Universidad Cato
´lica de
Valparaı
´so, Av. Brasil 2241 Valparaı
´so, Chile.
e-mail: roberto.chavez@pucv.cl
Ariel A. Mun
˜oz is a Professor at the Instituto de Geografı
´a, Pontificia
Universidad Cato
´lica de Valparaı
´so. His research focuses on the
application of tree rings and their chemistry to understand the effects
of climate change on natural resources, cities, and forest ecosystems.
Address: Instituto de Geografı
´a, Pontificia Universidad Cato
´lica de
Valparaı
´so, Av. Brasil 2241 Valparaı
´so, Chile.
e-mail: ariel.munoz@pucv.cl
Fernanda Salinas is a Research Ecologist at the non-governmental
organization Fiscalı
´a del Medio Ambiente. Her research interests
include plant ecology and evolution, and the environmental impacts
of human activities.
Address: Fiscalı
´a del Medio Ambiente (ONG FIMA), Mosqueto 491,
of. 312, Santiago, Chile.
e-mail: salinas@fima.cl
A
´lvaro Gonza
´lez-Reyes is a Adjunct Professor at the Instituto de
Ciencias de la Tierra, Universidad Austral de Chile. His research
interests include climate change, water resources, extreme events, and
dendrochronology.
Address: Instituto de Ciencias de la Tierra, Facultad de Ciencias,
Universidad Austral de Chile, Campus Isla Teja, Casilla, 567 Val-
divia, Chile.
e-mail: gonzalezreyesalvaro@gmail.com
Ronald Rocco is a researcher of the Lab. of Geo-information and
Remote Sensing, Pontificia Universidad Cato
´lica de Valparaı
´so. His
research interests include optical remote sensing and forestry.
Address: Instituto de Geografı
´a, Pontificia Universidad Cato
´lica de
Valparaı
´so, Av. Brasil 2241 Valparaı
´so, Chile.
e-mail: r.roccogatica@gmail.com
Francisco de la Barrera is a Professor at the Department of Geog-
raphy, Universidad de Concepcio
´n. His research interests include
landscape ecology, urban ecology, ecosystem services, and sustain-
ability.
Address: Faculty of Architecture, Urbanism and Geography,
Universidad de Concepcion, Victor Lamas 1290, Concepcio
´n, Chile.
e-mail: fdelabarrera@udec.cl
Grant J. Williamson is a geospatial analyst and landscape ecologist
at the School of Natural Sciences, University of Tasmania. His
research interests include landscape to global scale pyrogeography,
wildfire smoke transport, and human exposure.
Address: School of Natural Sciences, University of Tasmania, Private
Bag 55, Hobart, TAS 7001, Australia.
e-mail: grant.williamson@utas.edu.au
Nicola
´s Borchers is a doctoral candidate at the Menzies Institute for
Medical Research, University of Tasmania. His research interests
include the health and economic impacts of air pollution, environ-
mental and energy policy, and policy-related data science.
Address: Menzies Institute for Medical Research, University of
Tasmania, Private Bag 23, Hobart, TAS 7001, Australia.
e-mail: nicolas.borchers@utas.edu.au
Luis A. Cifuentes is an Associate Professor from the Department of
Industrial and Systems Engineering, Pontificia Universidad Cato
´lica
de Chile. His research interests include environmental management,
economics and policy; environmental risk assessment; air pollution
impacts; and risk perception.
Address: Industrial and Systems Engineering Department, Pontificia
Universidad Cato
´lica de Chile, Avda. Vicun
˜a Mackenna 4860, Macul,
Santiago, Chile.
e-mail: lac@ing.puc.cl
John T. Abatzoglou is an Associate Professor of Geography at
College of Science, University of Idaho. His research interests include
climate variability and change and impacts on natural and human
systems.
Address: College of Science, University of Idaho, Moscow, ID
83844-3021, USA.
e-mail: jabatzoglou@uidaho.edu
Fay H. Johnston is a public health physician and environmental
epidemiologist at the Menzies Institute for Medical Research,
University of Tasmania. Her research interests include the health
impacts of wildfires and air pollution.
Address: Menzies Institute for Medical Research, University of
Tasmania, Private Bag 23, Hobart, TAS 7001, Australia.
e-mail: fay.johnston@utas.edu.au
ÓRoyal Swedish Academy of Sciences 2018
www.kva.se/en 123
Ambio
... Los incendios forestales se reconocen cada vez más como un peligro natural que puede causar importantes daños sociales, económicos y ambientales, se constituyen como uno de los mayores agentes de degradación de los ecosistemas, que se ha intensificado por el cambio climático global, impactando en la sequedad de vegetación (Arroyo et al., 2019;Bowman et al., 2019;Fernández et al., 2010). En este sentido, los incendios son una perturbación negativa en los ecosistemas aledaños a sistemas urbano-rurales, estos han generado cambios en la estructura de los bosques, pérdida de suelos fértiles, contaminación atmosférica, desertificación y consecuentemente una disminución en los servicios ecosistémicos, entre otros (Alcañiz et al., 2018;CONAF, 2017;Úbeda & Sarricolea, 2016). ...
... En este sentido, algunos tipos de vegetación como eucaliptos son intrínsicamente más inflamables que otros, por lo que representan un mayor riesgo cuando se encuentran cercanos a asentamientos humanos. La extensión de incendios y los usos de suelo como plantaciones y urbanización aumentan la probabilidad de que se produzcan incendios (Bowman et al., 2019). ...
... En este sentido, la distribución de la vegetación nativa es heterogénea y se desarrolla a diversas escalas. Esto quiere decir que, dentro de una misma zona, los efectos de incendios serán variados según las condiciones bióticas, abióticas, y las coberturas del suelo (Bowman et al., 2019;CONAF, 2017). ...
Thesis
Full-text available
Forest fires are considered one of the major agents of ecosystem degradation, generating negative social, economic and environmental effects. The objective of this research was to evaluate the impact of the 2017 mega forest fire in the Vichuquén micro-watershed on the provision of cultural ecosystem services. The methodology used corresponds to quantitative and qualitative methods such as; supervised land cover classification, NBRI index to determine the level of severity, as well as biophysical valuation of ecosystem services. The qualitative methodology developed corresponds to the identification of the biophysical attributes of the landscape, through a semi-structured survey and interviews with local stakeholders. The main results show changes in land cover, mainly dominated by forest plantations, with the highest level of severity in these areas. There is a slow recovery of the landscape, favored by native forest and scrub cover. Landscape attributes provided by water bodies, protected areas and socio-cultural elements that increase the provision of cultural ecosystem services are highlighted. The conclusions of this research account for an increase in the cultural ecosystem service after the mega fire 2017, associated with recreational opportunities in addition to the historical cultural value of Vichuquén, it is necessary to generate participatory ecological restoration processes for those areas most affected, allowing an articulation between biophysical aspects towards a social articulation based on conservation with the actors of the territory.
... Además, pueden modificar, en el corto y mediano plazo, al clima local, a los procesos ecosistémicos, y a la tasa de emisión de gases y partículas (Harper et al., 2018). También cambian las coberturas del suelo, teniendo como consecuencia la pérdida de los servicios ecosistémicos que ofrecían las coberturas terrestres antes de la ocurrencia de los mega-incendios, siendo la pérdida aún más crítica cuando los incendios ocurren cerca de zonas urbanas o áreas muy pobladas (De la Bowman et al., 2018). ...
... Sin embargo, desde el siglo XX el cambio climático y las condiciones meteorológicas favorables para los incendios que genera, junto al cambio de uso de suelos que favorece una cubierta domínate que es altamente combustible, homogénea e incluye vegetación pirrófitas, han generado una modificación en los regímenes de incendios hacia un aumento de su frecuencia y magnitud, haciendo a los paisajes mediterráneos aún más propensos a incendios forestales (Lasanta et al., 2018;San Miguel-Ayanz et al., 2013). En Chile, la ocurrencia de incendios y mega-incendios forestales ha aumentado en los últimos años, siendo sus zonas de clima mediterráneo, donde domina la vegetación de tipo esclerófila, las plantaciones forestales y los suelos agrícolas, las más afectadas (Altamirano et al., 2013;Bowman et al. 2018). A principios del 2017, mega-incendios afectaron la zona centro-sur de Chile quemando plantaciones forestales, bosques nativos, matorrales, e incluso, asentamientos humanos. ...
... En el mundo prácticamente ninguna región con vegetación está exenta a los incendios forestales, sin embargo, las regiones de clima semiárido o de clima mediterráneos los incendios forestales son fundamentales en la ecología y la evolución de la flora y a la vez un importante agente de perturbación (Urrutia-Jalabert et al., 2018), pero también son la mayor perturbación económica desde una perspectiva socioeconómica y ecológica, es uno de los principales problemas ambientales y son más propensas a estos, además su frecuencia y gravedad han aumentado en las últimas décadas y se estima que esto siga aumentando en los próximos años, afectando la composición y estructura de bosques naturales y plantaciones forestales (Lasanta et al., 2018;Castillo et al., 2017;Massetti, 2019;Castillo et al., 2020;Promis et al., 2019). Los países más afectados se encuentran China en 1987, Portugal en 2003 y 2005, Australia 2003 y 2009, Grecia 2007, Canadá 2016 y Australia para la temporada 2019-2020, esta frecuencia que va en aumento se le atribuye principalmente a la acumulación de combustible promovida por el abandono de tierras y a las alteraciones ecológicas desencadenadas por el cambio climático, que contribuye a la sequedad de la vegetación y a incrementar la incidencia de incendios extremos (Pliscoff et al., 2020;Bowman et al., 2018). Los incendios forestales no son exclusivamente un fenómeno climático, también tienen dimensiones biológicas y humanas. ...
Thesis
Full-text available
Extreme fire episodes, also known as megafires, often refer to wildfires that cause catastrophic damage in terms of human life, economic loss, or both. These megafires change the land cover, resulting in the loss of the ecosystem services provided by the land cover before the mega-fires occurred. This loss is even more critical when fires occur near urban areas or heavily populated areas. At the beginning of 2017, megafires affected the south-central zone of Chile, affecting forest plantations, native forests, scrublands, and even human settlements. The Maule Region had 287,027 of the 529,974 hectares affected at the macro-regional level, the coastal sector of the region (including the Costal range) being strongly impacted. The objective of this work is to evaluate how a large forest fire modifies the configuration of the micro-basin landscape and how this influences the provision of multiple ecosystem services on an inter-annual basis, considering a biophysical approach based on experts and remote sensing techniques. For this, the Estero Empedrado micro-basin was analyzed, which was affected by 59% by the fire called “Las Máquinas”, covering a total area of 183,946 ha. The landscape assessment was based on the classification of the covers using Sentinel-2 images in conjunction with three multispectral indicators: NBRI, BAIS-2 and NDVI. Meanwhile, the provision of ecosystem services was biophysically an expert-based matrix where values are attributed to the capacity of each ecosystem to provide ecosystem services, being directly linked to the behavior of spectral indices and coverage, presented through graphs and cartographies. The results indicate that the studied area was contracted by the great forest fire, reducing its supply capacity by half, being even more serious since this supply was already low and with few ecosystem services. Those ecosystem services most affected were regulatory and cultural services. The use of the indices shows a high correlation, with respect to the severity indices it shows similar information, however, BAIS-2 is more sensitive to post-fire regeneration changes and NDVI works better to discriminate healthy and burning vegetation. The land cover that provides the most ecosystem services is the native forest, so its restoration is key to recovering the provision of services. The methodology designed is applicable for areas affected by forest fires between the regions from O'Higgins to Ñuble. It is recommended to extend this analysis to a minimum of 10 years, for which it would currently be necessary to use Landsat images, or wait 5 more years to be able to replicate the use of Sentinel images, which have better spatial resolution.
... In Chile, lying between the subtropical south-eastern Pacific and the Andes Cordillera (17°S to 56°S), recent HWs have provoked large ecosystem losses. For instance, during January 2017, daily maximum air temperature continuously reached values above 30ºC between 30º to 40ºS, and ~ 5000 km 2 of native forest and exotic plantations were burned during the so-called "firestorm" (Bowman et al., 2019), i.e. ten times the average area burned in the previous 40 years as has been reported by Urrutia-Jalabert et al. (2018). Despite Chile's environmental consequences during the "firestorm" in 2017, the study on HWs in Chile has received small attention to date. ...
... Since 2010, Central and South-Central Chile have been experiencing a so-called megadrought (Garreaud et al., 2017). Hence, higher daily Tx might result in more intense and/or more persistent HWs, such as those events identified during 2017 that induce severe wildfires and impacts (more than 5000 km 2 burned in Central Chile; Bowman et al., 2019). We speculate that the persistent dry conditions registered in Chile since 2010 have played a key role for the increase in HW frequency during 2011-2020 in Chile here reported. ...
... During the Megadrought in Central Chile, the number, area, simultaneity, and duration of large fires increased significantly compared with the previous 10-year period [34]. The fires of the 2016-2017 summer burned an area that was 14 times the mean for the period 1985-2016 and the highest on record till then [35]. This megafire was one of the severest ever recorded, burning in three weeks an area close to 350,000 hectares in south-central Chile [36] and was also associated with the prolonged drought and increase of heatwaves [37]. ...
Article
Full-text available
Climate change should deteriorate the value of real estate, but studies are lacking for developing economies which may suffer the worst weather changes. We match an administrative register of all the real estate properties’ transactions in Chile between 2002 and 2020 with a high spatial resolution dataset of local temperatures and precipitation. Even after controlling for a wide set of home characteristics or fixed-effects for each property, we find that fluctuations in temperatures had an impact on the prices of residential homes and agricultural properties.
... Large fires are increasing in frequency on a global scale, especially due to climate change and the accumulation of available fuel to burn (Bowman et al., 2018;Rogers et al., 2020). Population growth and the growing demand for second homes or recreational homes in forest areas increase the vulnerability to forest fires (Reams et al., 2005;Castillo, 2006). ...
Article
Full-text available
Wildfires in the urban-forest interface constitute a civil protection emergency, causing considerable personal injury and damage to properties. The potential impacts of wildfires on buildings can be minimized by reducing the surrounding fuel and the use of structural materials with low flammability. However, the costs associated with implementing these actions and the responsibility for maintenance usually present conflicts with the property owners. This study aimed to identify minimum safety distances in wildland-urban interfaces within priority areas. The priority areas were identified based on the integration of fire risk and fuel hazard. Radiant heat is a variable in the behavior of fire that directly influences the definition of safety distances. In this research the radiant heat transfer was calculated based on the potential fire behavior for each study area. A comparative study of the horizontal heat transfer method and the radiant heat flux model was carried out. The horizontal heat transfer method indicated the highest vegetation-free distances, ranging from 23 m to 32 m. Some safety distances were validated using experimental fires and wildfires. The findings from the experimental fires and wildfires emphasize the need for a progressive fuel load reduction to mitigate radiant heat transfer. This may include both the removal of surface fuel and removal of trees to mitigate against crown fires. Our findings provide relevant information for decision-making on the effectiveness and efficiency of safety distances at the wildland-urban interface.
... Wildfires in Chile have caused significant human, ecological and economic damage to cities, protected areas, and the economy (Reszka and Fuentes 2014;Bowman et al. 2018). Climate change is expected to increase the occurrence and severity of these events (McWethy et al. 2018;Pausas and Keeley 2021;United Nations Environment Programme 2022). ...
Chapter
O período entre 2018 e 2022 mostrou-nos que o problema dos incêndios à escala global não está a diminuir, antes pelo contrário. Parece que as consequências das alterações climáticas já estão a afectar a ocorrência de incêndios florestais em várias partes do Mundo, de uma forma que só esperaríamos que acontecesse vários anos mais tarde. Em muitos países do Sul da Europa, bem como em algumas regiões dos EUA, Canadá e Austrália, onde estamos habituados a enfrentar a presença de incêndios muito grandes e devastadores, continuamos a ter eventos que quebram recordes. Alguns países, como os da Europa Central e do Norte, que não estavam habituados a ter grandes incêndios, experimentaram-nos durante estes anos. Os anos anteriores foram muito exigentes para todo o Mundo, também noutros aspectos que nos afectaram a todos. Referimo-nos às restrições impostas pela pandemia que limitaram as nossas reuniões e viagens, afectando em muitos casos a saúde dos membros da Comunidade Científica Wildfire. Felizmente, conseguimos encontrar novas formas de comunicação, ultrapassar essas limitações e manter-nos em contacto uns com os outros. Durante semanas e meses, para muitos de nós, as reuniões pessoais e o trabalho de grupo foram substituídos por ligações em linha. Apesar da economia de dinheiro e tempo, e da facilidade de reunir uma grande variedade de pessoas que estas reuniões desde que nos apercebêssemos de que não substituem as reuniões presenciais, que trazem consigo outras dimensões inestimáveis, que fazem parte da comunicação pessoal e ajudam a construir uma comunidade científica.
... From this, we obtained information on the coordinates, start date, control, cause, and magnitude, of the fires that occurred in the Maule region between 2013 and 2015. The period defined for collecting information was due to the need to have a rich source of It should be noted that in Empedrado, the town of Santa Olga was entirely consumed by the fire, becoming an emblematic case of megafires' impact on a population in a WUI [15,67]. The incident negatively impacted the water and electricity supply and generated contamination of water sources for human and animal consumption. ...
Article
Full-text available
Wildland fires are a phenomenon of broad interest due to their relationship with climate change. The impacts of climate change are related to a greater frequency and intensity of wildland fires. In this context, megafires have become a phenomenon of particular concern. In this study, we develop a model of ignition risk. We use factors such as human activity, geographic, topographic, and land cover variables to develop a bagged decision tree model. The study area corresponds to the Maule region in Chile, a large zone with a Mediterranean climate. This area was affected by a megafire in 2017. After generating the model, we compared three interface zones, analyzing the scar and the occurrences of ignition during and after the megafire. For the construction of georeferenced data, we used the geographic information system QGIS. The results show a model with high fit goodness that can be replicated in other areas. Fewer ignitions are observed after the megafire, a high recovery of urban infrastructure, and a slow recovery of forest plantations. It is feasible to interpret that the lower number of ignitions observed in the 2019–2020 season is a consequence of the megafire scar. It is crucial to remember that the risk of ignition will increase as forest crops recover. Wildland fire management requires integrating this information into decision-making processes if we consider that the impacts of climate change persist in the area.
... In many parts of the world, forest disturbances have been intensified, and climate change is expected to amplify this trend, compromising profoundly forest carbon stocks and sinks in the future (Seidl et al., 2017). For instance, in recent years, forest landscapes in south-central Chile have experienced the largest wildfires of the past 50 years associated with dry and warm climate conditions (Bowman et al., 2018;González et al., , 2020Urrutia-Jalabert et al., 2018b;Garreaud et al., 2020). In this region, 99% of the fires are caused by humans (Pozo et al., 2022), and the risk of fires is increasing with climate change (Veblen et al., 2011;Urrutia-Jalabert et al., 2018b;IPCC, 2022), so stronger prevention and control programs for wildfires are needed. ...
Article
Full-text available
Forest disturbances influence Fitzroya cupressoides forest structure and carbon stocks at multiple spatial and temporal scales. Natural disturbances such as landslides and volcanism affect and give rise to the mostly pristine Fitzroya stands present in the Andean cordillera. On the other hand, mostly human-caused fires and logging have been the main processes shaping the structure of Fitzroya stands in the Coastal range and of Fitzroya small remnants in the Central depression. The main goal of this study was to assess the carbon stocks and accumulation rates of Fitzroya forest stands according to their development stage under different disturbance regimes and environmental conditions given by the three physiographic units where the species grows (Coastal range, Central depression, and Andean range). The site selection included an age sequence of stands, known as a chronosequence approach. We identified Fitzroya post-disturbance stands in three different stages of development: young forest stage (mean stand age of the main cohort ≤ 200 years old), mature forest stage (200–800 years old), and old growth forest stage (800–1,500 years old). The following biomass components were considered: living standing trees, dead standing trees (snags), and logs from dead trees laying on the ground (coarse woody debris). Old-growth Fitzroya forests reached a mean total carbon stock (standing live trees, snags, and coarse woody debris) of 507, 279, and 331 Mg C ha ⁻¹ in the Andean and Coastal ranges, and Central depression, respectively. Fitzroya cupressoides contributes, in average, more than 80% to the total carbon stock in the Andean and Coastal ranges, and 63% in the Central depression. The remainder corresponds mainly to Nothofagus spp. The high carbon stocks in old-growth stands in the Andean range are explained by Fitzroya longevity, larger size, wood decay resistance, and the low recurrence of volcanic events. Carbon accumulation rates differ between the forests in the three physiographic units (Central depression>Andean range>Coastal range), mainly due to the different growth rates and environmental conditions present in each unit. In the context of climate change, conserving old-growth stands with large biomass and carbon stocks and restoring Fitzroya forests should be recognized as a key contribution toward national and global goals to mitigate global warming.
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Nothofagus alessandrii , categorized as Endangered on the IUCN Red List, is an endemic, deciduous tree species of the coastal range of central Chile. We assessed the effects of fire severity, invasion by the exotic fire-prone Pinus radiata , and land-cover composition and configuration of the landscape on the resilience of fragments of N. alessandrii after a mega-fire in 2017. We used remote sensing data to estimate land-use classes and cover, fire severity and invasion cover of P. radiata . We monitored forest composition and structure and post-fire responses of N. alessandrii forests in situ for 2 years after the mega-fire. In the coastal Maule region wildfires have been favoured by intense drought and widespread exotic pine plantations, increasing the ability of fire-adapted invasive species to colonize native forest remnants. Over 85% of N. alessandrii forests were moderately or severely burnt. The propagation and severity of fire was probably amplified by the exotic pines located along the edges of, or inside, the N. alessandrii fragments and the highly flammable pine plantations surrounding these fragments (> 60% of land use is pine plantations). Pinus radiata , a fire-adapted pioneer species, showed strong post-fire recruitment within the N. alessandrii fragments, especially those severely burnt. Positive feedback between climate change (i.e. droughts and heat waves), wildfires and pine invasions is driving N. alessandrii forests into an undesirable and probably irreversible state (i.e. a landscape trap). A large-scale restoration programme to design a diverse and less flammable landscape is needed to avoid the loss of these highly threatened forest ecosystems.
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Changing frequencies of extreme weather events and shifting fire seasons call for enhanced capability to forecast where and when forested landscapes switch from a non-flammable (i.e. wet fuel) state to the highly flammable (i.e. dry fuel) state required for catastrophic forest fires. Current forest fire danger indices used in Europe, North America and Australia rate potential fire behaviour by combining numerical indices of fuel moisture content, potential rate of fire spread, and fire intensity. These numerical rating systems lack the physical basis required to reliably quantify forest flammability outside the environments of their development or under novel climate conditions. Here, we argue that exceedance of critical forest flammability thresholds is a prerequisite for major forest fires and therefore early warning systems should be based on a reliable prediction of fuel moisture content plus a regionally calibrated model of how forest fire activity responds to variation in fuel moisture content. We demonstrate the potential of this approach through a case study in Portugal. We use a physically-based fuel moisture model with historical weather and fire records to identify critical fuel moisture thresholds for forest fire activity and then show that the catastrophic June 2017 forest fires in central Portugal erupted shortly after fuels in the region dried out to historically unprecedented levels.
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Wildfires cause different impacts, depending on the conditions and resilience level of the exposed communities. Wildfire occurrence in mainland Portugal was assessed with regard to socioeconomic and demographic parameters, to identify the most distinctive conditions of fire-affected areas, without implying the existence of causal relationships. The latest population and agriculture census data were used to retrieve conditions at the civil parish level, regarding demographic patterns, social and labor conditions, physical structures and agricultural activities. To identify differences between parishes, two groups were created with the communities that showed the highest and lowest 20% of wildfire incidence between 2007 and 2014, separately for density of fire events and for burned area. A stepwise approach based on classification trees and random forest methods was applied to identify the best discriminant variables between the groups. First, irrelevant variables were removed by an interactive process based on misclassification rates. The second step used random Forest analysis to the remaining variables to evaluate their importance in distinguishing the groups. In the final step, cluster analysis was applied to test the correspondence between the clusters created with the selected variables and the initial groups. Results showed that parishes with higher fire density have higher population density, higher proportion of young and educated people, larger families and more overcrowded buildings. On the contrary, parishes with larger burned area are less populated, less attractive to foreigners, have a higher proportion of elderly people, more degraded housing conditions and agricultural activities are still relevant. The cluster analysis demonstrated a better performance of the model for wildfire density, revealing a strong association with socioeconomic dynamics with an agreement above 0.85, much higher than for burned areas which is 0.29. Overall, the spatial distribution of wildfire impacts is framed by societal settings and particular conditions must be further understood to improve the coping capacity of affected communities.
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