A Relationship Between Rainfall and Burned Area for Portugal

1994 ◽  
Vol 4 (1) ◽  
pp. 11 ◽  
Author(s):  
DX Viegas ◽  
MT Viegas
Keyword(s):  
Early Spring ◽  
Wide Area ◽  
Fire Season ◽  
Burned Area ◽  
Weather Station ◽  
Inverse Relation ◽  
Area Burned ◽  
Water Reserve ◽  
Area Data

Total area burned yearly in Portugal in the period of 1975 to 1992 is related to rainfall during particular periods of the year. Precipitation in the period of January to April, corresponding to Winter and early Spring, related to fine fuel growth and to the water reserve in the soil, shows a non monotonic relationship with burned area each year, due to the conflicting mechanisms of the these two processes. Rainfall between June and September, corresponding to the main fire season in Portugal, exhibits an inverse relation with burned area. Data of a single weather station were used in the analysis and it was demonstrated that they are representative of a wide area in the country.

scholarly journals Decreasing fire season precipitation increased recent western US forest wildfire activity

2018 ◽  
Vol 115 (36) ◽  
pp. E8349-E8357 ◽  
Author(s):  
Zachary A. Holden ◽  
Alan Swanson ◽  
Charles H. Luce ◽  
W. Matt Jolly ◽  
Marco Maneta ◽  
...  
Keyword(s):  
United States ◽  
Surface Air Temperature ◽  
Summer Precipitation ◽  
Western United States ◽  
Fire Season ◽  
Burned Area ◽  
Evaporative Demand ◽  
Near Surface ◽  
Area Burned ◽  
Fire Activity

Western United States wildfire increases have been generally attributed to warming temperatures, either through effects on winter snowpack or summer evaporation. However, near-surface air temperature and evaporative demand are strongly influenced by moisture availability and these interactions and their role in regulating fire activity have never been fully explored. Here we show that previously unnoted declines in summer precipitation from 1979 to 2016 across 31–45% of the forested areas in the western United States are strongly associated with burned area variations. The number of wetting rain days (WRD; days with precipitation ≥2.54 mm) during the fire season partially regulated the temperature and subsequent vapor pressure deficit (VPD) previously implicated as a primary driver of annual wildfire area burned. We use path analysis to decompose the relative influence of declining snowpack, rising temperatures, and declining precipitation on observed fire activity increases. After accounting for interactions, the net effect of WRD anomalies on wildfire area burned was more than 2.5 times greater than the net effect of VPD, and both the WRD and VPD effects were substantially greater than the influence of winter snowpack. These results suggest that precipitation during the fire season exerts the strongest control on burned area either directly through its wetting effects or indirectly through feedbacks to VPD. If these trends persist, decreases in summer precipitation and the associated summertime aridity increases would lead to more burned area across the western United States with far-reaching ecological and socioeconomic impacts.

scholarly journals Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 522
Author(s):  
Akli Benali ◽  
Ana C. L. Sá ◽  
João Pinho ◽  
Paulo M. Fernandes ◽  
José M. C. Pereira
Keyword(s):  
Management Strategies ◽  
Treatment Strategies ◽  
Fire Season ◽  
Burned Area ◽  
Treatment Area ◽  
Fuel Treatment ◽  
The North ◽  
Wildfire Hazard ◽  
Central Portugal ◽  
The Impact

The extreme 2017 fire season in Portugal led to widespread recognition of the need for a paradigm shift in forest and wildfire management. We focused our study on Alvares, a parish in central Portugal located in a fire-prone area, which had 60% of its area burned in 2017. We evaluated how different fuel treatment strategies may reduce wildfire hazard in Alvares through (i) a fuel break network with different extents corresponding to different levels of priority and (ii) random fuel treatments resulting from a potential increase in stand-level management intensity. To assess this, we developed a stochastic wildfire simulation system (FUNC-SIM) that integrates uncertainties in fuel distribution over the landscape. If the landscape remains unchanged, Alvares will have large burn probabilities in the north, northeast and center-east areas of the parish that are very often associated with high fireline intensities. The different fuel treatment scenarios decreased burned area between 12.1–31.2%, resulting from 1–4.6% increases in the annual treatment area and reduced the likelihood of wildfires larger than 5000 ha by 10–40%. On average, simulated burned area decreased 0.22% per each ha treated, and cost-effectiveness decreased with increasing area treated. Overall, both fuel treatment strategies effectively reduced wildfire hazard and should be part of a larger, holistic and integrated plan to reduce the vulnerability of the Alvares parish to wildfires.

scholarly journals Demographic Effects of Severe Fire in Montane Shrubland on Tasmania’s Central Plateau

Fire ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 32
Author(s):  
Judy A. Foulkes ◽  
Lynda D. Prior ◽  
Steven W. J. Leonard ◽  
David M. J. S. Bowman
Keyword(s):  
Woody Species ◽  
Fire Frequency ◽  
Fire Season ◽  
Burned Area ◽  
Large Area ◽  
Seedling Regeneration ◽  
Central Plateau ◽  
Conservation Area ◽  
Severe Fire ◽  
Representative Area

Australian montane sclerophyll shrubland vegetation is widely considered to be resilient to infrequent severe fire, but this may not be the case in Tasmania. Here, we report on the vegetative and seedling regeneration response of a Tasmanian non-coniferous woody montane shrubland following a severe fire, which burned much of the Great Pine Tier in the Central Plateau Conservation Area during the 2018–2019 fire season when a historically anomalously large area was burned in central Tasmania. Our field survey of a representative area burned by severe crown fire revealed that more than 99% of the shrubland plants were top-killed, with only 5% of the burnt plants resprouting one year following the fire. Such a low resprouting rate means the resilience of the shrubland depends on seedling regeneration from aerial and soil seedbanks or colonization from plants outside the burned area. Woody species’ seedling densities were variable but generally low (25 m−2). The low number of resprouters, and reliance on seedlings for recovery, suggest the shrubland may not be as resilient to fire as mainland Australian montane shrubland, particularly given a warming climate and likely increase in fire frequency.

scholarly journals Global estimation of burned area using MODIS active fire observations

2006 ◽  
Vol 6 (4) ◽  
pp. 957-974 ◽  
Author(s):  
L. Giglio ◽  
G. R. van der Werf ◽  
J. T. Randerson ◽  
G. J. Collatz ◽  
P. Kasibhatla
Keyword(s):  
Vegetation Cover ◽  
Regression Trees ◽  
The United States ◽  
Tree Cover ◽  
Burned Area ◽  
Data Set ◽  
Active Fire ◽  
Terra Modis ◽  
Good Agreement ◽  
Area Data

Abstract. We present a method for estimating monthly burned area globally at 1° spatial resolution using Terra MODIS data and ancillary vegetation cover information. Using regression trees constructed for 14 different global regions, MODIS active fire observations were calibrated to burned area estimates derived from 500-m MODIS imagery based on the assumption that burned area is proportional to counts of fire pixels. Unlike earlier methods, we allow the constant of proportionality to vary as a function of tree and herbaceous vegetation cover, and the mean size of monthly cumulative fire-pixel clusters. In areas undergoing active deforestation, we implemented a subsequent correction based on tree cover information and a simple measure of fire persistence. Regions showing good agreement between predicted and observed burned area included Boreal Asia, Central Asia, Europe, and Temperate North America, where the estimates produced by the regression trees were relatively accurate and precise. Poorest agreement was found for southern-hemisphere South America, where predicted values of burned area are both inaccurate and imprecise; this is most likely a consequence of multiple factors that include extremely persistent cloud cover, and lower quality of the 500-m burned area maps used for calibration. Application of our approach to the nine remaining regions yielded comparatively accurate, but less precise, estimates of monthly burned area. We applied the regional regression trees to the entire archive of Terra MODIS fire data to produce a monthly global burned area data set spanning late 2000 through mid-2005. Annual totals derived from this approach showed good agreement with independent annual estimates available for nine Canadian provinces, the United States, and Russia. With our data set we estimate the global annual burned area for the years 2001-2004 to vary between 2.97 million and 3.74 million km2, with the maximum occurring in 2001. These coarse-resolution burned area estimates may serve as a useful interim product until long-term burned area data sets from multiple sensors and retrieval approaches become available.

scholarly journals PERFIL DOS INCÊNDIOS FLORESTAIS NO BRASIL DE 1994 A 1997

FLORESTA ◽  
2002 ◽  
Vol 32 (2) ◽  
Author(s):  
Ronaldo Viana Soares ◽  
Juliana Ferreira Santos
Keyword(s):  
Forest Fire ◽  
Vegetation Type ◽  
Secondary Growth ◽  
Minas Gerais ◽  
Size Class ◽  
Fire Season ◽  
Burned Area ◽  
Native Forest ◽  
Fire Statistics ◽  
Fire Control

O conhecimento do perfil dos incêndios florestais é muito importante para o planejamento do controle dos mesmos. O objetivo deste trabalho foi estabelecer o perfil dos incêndios florestais no país através de dados coletados, em áreas protegidas, no período de 1994 a 1997, através de formulários preenchidos por empresas e instituições florestais. Foram registrados e informados 1.957 incêndios e apesar deste número não representar a totalidade dos incêndios ocorridos no período estudado, constituiu-se numa base confiável para se conhecer as principais características dos incêndios. Os resultados mostraram que a área média atingida por incêndio no período analisado foi de aproximadamente 135 ha, sendo Minas Gerais o estado líder, tanto em número de incêndios informados (62,7% do total) como em área queimada (25,2%). O grupo Incendiários foi a principal causa dos incêndios, com 56,6% das ocorrências, vindo a seguir as Queimas para limpeza com 22,1%. Com relação à área queimada o grupo Queimas para limpeza , com 74,1% da superfície atingida, foi a principal causa, ficando o grupo Incendiários em segundo lugar com 19,8%. A principal estação de incêndios no país se estende de julho a novembro, quando ocorreram 79,2% dos incêndios, correspondendo a 98,6% da área atingida. O maior número de incêndios (39,7% das ocorrências) foi registrado em Outro tipo de vegetação, que inclui cerrado, capoeira e campo. Com relação à área atingida, entretanto, 92,5% foi registrada em Florestas Nativas. Quanto à distribuição dos incêndios através das classes de tamanho, 23,9% foi enquadrado na classe I ( 0,1 ha). É importante ressaltar que quanto maior a eficiência no combate aos incêndios, maior é a concentração dos mesmos na classe I. Apesar de corresponder a apenas 2,4% das ocorrências, os incêndios da classe V ( 200,0 ha) foram responsáveis por 94,5% da área queimada. FOREST FIRE STATISTICS IN BRAZIL FROM 1994 TO 1997 Abstract Forest fire statistics knowledge is an important tool for fire control planning. The objective of this research was to collect information on forest fire occurrence in Brazilian protected areas in the period of 1994 to 1997. The analyzed variables were the number of fires and burned areas per state of the federation, monthly distribution, probable causes, affected vegetation, size class distribution, and average burned area per fire. Results showed that the average burned area per fire was approximately 135 ha and Minas Gerais ranked first, both in number of registered fires (62.7%) and burned surface (25.2%). Incendiary, with 56.6% of the occurrences was the leading cause, followed by debris burning with 22.1%. However, as for the affected area, Debris burning was the leading cause (74.1%), followed by Incendiary (19.8%). The fire season extends from July to November, when 79.2% of the fires occurred, corresponding to 98.6% of the burned surface. Miscellaneous, that includes savanna, secondary growth forest, and grassland were the most affected vegetation type (39.7% of the occurrences). In relation to the burned surface, Native Forest (92.5%) ranked first. The distribution of the registered fires through the size classes presented 23.9% of the occurrences in Class I ( 0.1 ha), whereas 94.5% of the burned area were result of Class V ( 200 ha) fires. Size Class II (0.1 to 4.0 ha), with 49.1% of the occurrences, ranked first in number of registered fires during the analyzed period.

scholarly journals Estimates of biomass burning emissions in tropical Asia based on satellite-derived data

2010 ◽  
Vol 10 (5) ◽  
pp. 2335-2351 ◽  
Author(s):  
D. Chang ◽  
Y. Song
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Crop Residue ◽  
Fire Season ◽  
Burned Area ◽  
Published Data ◽  
Tropical Asia ◽  
Fire Emissions ◽  
Burned Areas ◽  
In Fire

Abstract. Biomass burning in tropical Asia emits large amounts of trace gases and particulate matter into the atmosphere, which has significant implications for atmospheric chemistry and climatic change. In this study, emissions from open biomass burning over tropical Asia were evaluated during seven fire years from 2000 to 2006 (1 March 2000–31 February 2007). The size of the burned areas was estimated from newly published 1-km L3JRC and 500-m MODIS burned area products (MCD45A1). Available fuel loads and emission factors were assigned to each vegetation type in a GlobCover characterisation map, and fuel moisture content was taken into account when calculating combustion factors. Over the whole period, both burned areas and fire emissions showed clear spatial and seasonal variations. The size of the L3JRC burned areas ranged from 36 031 km2 in fire year 2005 to 52 303 km2 in 2001, and the MCD45A1 burned areas ranged from 54 790 km2 in fire year 2001 to 148 967 km2 in 2004. Comparisons of L3JRC and MCD45A1 burned areas using ground-based measurements and other satellite data were made in several major burning regions, and the results suggest that MCD45A1 generally performed better than L3JRC, although with a certain degree of underestimation in forest areas. The average annual L3JRC-based emissions were 123 (102–152), 12 (9–15), 1.0 (0.7–1.3), 1.9 (1.4–2.6), 0.11 (0.09–0.12), 0.89 (0.63–1.21), 0.043 (0.036–0.053), 0.021 (0.021–0.023), 0.41 (0.34–0.52), 3.4 (2.6–4.3), and 3.6 (2.8–4.7) Tg yr−1 for CO2, CO, CH4, NMHCs, NOx, NH3, SO2, BC, OC, PM2.5, and PM10, respectively, whereas MCD45A1-based emissions were 122 (108–144), 9.3 (7.7–11.7), 0.63 (0.46–0.86), 1.1 (0.8–1.6), 0.11 (0.10–0.13), 0.54 (0.38–0.76), 0.043 (0.038–0.051), 0.033 (0.032–0.037), 0.39 (0.34–0.47), 3.0 (2.6–3.7), and 3.3 (2.8–4.0) Tg yr−1. Forest burning was identified as the major source of the fire emissions due to its high carbon density. Although agricultural burning was the second highest contributor, it is possible that some crop residue combustion was missed by satellite observations. This possibility is supported by comparisons with previously published data, and this result may be due to the small size of the field crop residue burning. Fire emissions were mainly concentrated in Indonesia, India, Myanmar, and Cambodia. Furthermore, the peak in the size of the burned area was generally found in the early fire season, whereas the maximum fire emissions often occurred in the late fire season.

scholarly journals Needle Senescence Affects Fire Behavior in Aleppo Pine (Pinus halepensis Mill.) Stands: A Simulation Study

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1054 ◽  
Author(s):  
Rodrigo Balaguer-Romano ◽  
Rubén Díaz-Sierra ◽  
Javier Madrigal ◽  
Jordi Voltas ◽  
Víctor Resco de Dios
Keyword(s):  
Mediterranean Basin ◽  
Fire Behavior ◽  
Western Mediterranean ◽  
Aleppo Pine ◽  
Fire Season ◽  
Burned Area ◽  
Crown Fire ◽  
Wind Speeds ◽  
Western Mediterranean Basin ◽  
Needle Senescence

Research Highlights: Pre-programmed cell death in old Aleppo pine needles leads to low moisture contents in the forest canopy in July, the time when fire activity nears its peak in the Western Mediterranean Basin. Here, we show, for the first time, that such needle senescence may increase fire behavior and thus is a potential mechanism explaining why the bulk of the annual burned area in the region occurs in early summer. Background and Objectives: The brunt of the fire season in the Western Mediterranean Basin occurs at the beginning of July, when live fuel moisture content is near its maximum. Here, we test whether a potential explanation to this conundrum lies in Aleppo pine needle senescence, a result of pre-programmed cell death in 3-years-old needles, which typically occurs in the weeks preceding the peak in the burned area. Our objective was to simulate the effects of needle senescence on fire behavior. Materials and Methods: We simulated the effects of needle senescence on canopy moisture and structure. Fire behavior was simulated across different phenological scenarios and for two highly contrasting Aleppo pine stand structures, a forest, and a shrubland. Wildfire behavior simulations were done with BehavePlus6 across a wide range of wind speeds and of dead fine surface fuel moistures. Results: The transition from surface to passive crown fire occurred at lower wind speeds under simulated needle senescence in the forest and in the shrubland. Transitions to active crown fire only occurred in the shrubland under needle senescence. Maximum fire intensity and severity were always recorded in the needle senescence scenario. Conclusions: Aleppo pine needle senescence may enhance the probability of crown fire development at the onset of the fire season, and it could partly explain the concentration of fire activity in early July in the Western Mediterranean Basin.

scholarly journals Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

2011 ◽  
Vol 11 (8) ◽  
pp. 3611-3629 ◽  
Author(s):  
T. T. van Leeuwen ◽  
G. R. van der Werf
Keyword(s):  
Temporal Variability ◽  
Field Measurement ◽  
Environmental Variables ◽  
Trace Gases ◽  
Measurement Techniques ◽  
Arithmetic Mean ◽  
Fire Season ◽  
Burned Area ◽  
Spatial And Temporal Variability ◽  
Fire Emissions

Abstract. Fires are a major source of trace gases and aerosols to the atmosphere. The amount of biomass burned is becoming better known, most importantly due to improved burned area datasets and a better representation of fuel consumption. The spatial and temporal variability in the partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors (EFs)) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome. In addition, it is unknown whether the available field measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH4, and CO2, our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different measurements of environmental variables that may correlate with part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were lower and explained about 33%, 38%, 19%, and 34% of the variability for respectively CO, CH4, CO2, and the Modified Combustion Efficiency (MCE). This may be partly due to uncertainties in the environmental variables, differences in measurement techniques for EFs, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of EF measurements. We derived new mean EFs, using the relative importance of each measurement location with regard to fire emissions. These weighted averages were relatively similar to the arithmetic mean. When using relations between the environmental variables and EFs to extrapolate to regional and global scales, we found substantial differences, with for savannas 13% and 22% higher CO and CH4 EFs than the arithmetic mean of the field studies, possibly linked to an underrepresentation of woodland fires in EF measurement locations. We argue that from a global modeling perspective, future measurement campaigns could be more beneficial if measurements are made over the full fire season, and if relations between ambient conditions and EFs receive more attention.

Development and field experiments of a human-portable towed ROV for high-speed and wide area data acquisition

2020 ◽  
Author(s):  
Norimitsu Sakagami ◽  
Keita Hirayama ◽  
Ryo Taba ◽  
Shota Kobashigawa ◽  
Seita Arashiro ◽  
...  
Keyword(s):  
Data Acquisition ◽  
High Speed ◽  
Field Experiments ◽  
Wide Area ◽  
Area Data
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