Em anos anteriores o lema na imprensa era
Amazônia em Chamas!.
Este ano estamos vendo
Pantanal em Chamas!..
Há a formação de uma
La Niña fraca
no oceano Pacífico,
e a região ~sudoeste do Brasil ficou mais seca, enquanto que
a região ~nordeste (provavelmente cerrado) e também a Amazônia
ficaram mais úmidas.
Decidi fazer uma lista genérica com possíveis causas naturais de incêndios florestais pois a imprensa parece saber somente de uma (incêndios criminosos), mas há uma literatura enquanto que enterrada pelo tempo, rica em informações relevantes, e muitas vezes, revelantes.
There started again the annual talk of forest fires!
In the last two years, the headlines were
Amazon is on fire!
and now they are
Pantanal is on fire!.
For those who are not familiar with what a Pantanal is, it is
actually a Brazilian ecosystem, which terrais flood in the
rain season and dry up in the dry season, so there are many bogs
and meandering rivers.
We are currently in the dry season! Also, this year it seems we are having a weak La Niña, which makes the Pantanal region (and where I live, some further south at the Capricorn Tropical Line), drier. On the other hand, the Amazon, cerrado and thereabouts in the northeast region, are in their turn more humid, and of course there are less forest fires there than the previous years.
I have been reading some material about fire management and found some very good Brazilian and Portuguese papers and documents. Specially, Portugal has got competent technical knowledge on the subject. In one the of the papers, after explaining Portugal fire index system through history (from ~1960), the author acknowledges the index could be far more useful for society if forest and fire management could make use of it!
I decided to start compiling a list of causes of forest fires other than criminal human or indigenous activity, which seems to be the only cause of forest fires the media knows and talks about.
This is a general list, forests may be more prone to some causes than others depending on geography and other factors. That is a shame I did not start making this list a few days ago, now it is rather hard to find some of the references and I can't be 100% sure about some technical wording, so while not ideal, I will link to similar references, leave them without reference or remove the item from the list eventually.
Causes of forest fires:
- Lightning storms (Fao), (Inpe), (University of Calgary), (Time)
- Accidental fires (from cigarette butts, fireworks, etc) and children play
- Bad fire usage in farming, criminous fires (such as balloon fire)
- Electrically-charged animal fur (friction with air, or vegetation) may produce an arc; friction between rocks; see also (a), (b)
- Dry weather, hot weather and other phenomena such as El Niño, La Niña , Pacific Decadal Oscillation (PDO), etc
- Expontaneous combustion phenomena
- Strong wind and/or poor maintenance of electrical transmission channels (Dn.pt), (WildfireMitigation)
- Focal lensing effect of sun rays (by water droplets, reflection from water, glassware)
- Meteors (CNA Brasil) , also NASA and "Impact-generated wildfires"
- Rodents (wire chewing) (Indiana Gov't), (PetsUSA)
- ?Fire/chacoal streams (geothermal ridges) [?context?]
- ?Some high-reactivity metals (such as Na and Zn) in contact with oxigen [?context?]
- Inpe fire monitoring stats
- Biology of Fire
- Fire as a key driver of Earth's biodiversity
- Smokey Bear
- Índice de Incêndio de Portugal
- PRODES - Monitoramento do Desmatamento da Floresta Amazônica Brasileira por Satélite
- Ignition time vs temperature for selected forest fuels
- Floresta em chamas (I don't agree with their conclusions but there are some good material, such as historical material)
- Holocene fire and vegetation changes in southeastern Brazil asdeduced from fossil charcoal and soil carbon isotopes
- Aspectos ecológicos do fogo no cerrado. II - As queimadas e a dispersão de sementes em algumas espécies anemocóricas do estrato herbáceo-subarbustivo / Ecological aspects of fire in the cerrado. II - Fire and seed dispersion in some anemochoric species of the herbaceous layer (1977), another copy here and also an extended version (1981)
- The need for a consistent fire policy for Cerrado conservation (2015), and also a copy from here
- Savanna turning into forest: concerted vegetation changeat the ecotone between the Amazon and "Cerrado" biomes, 2018 (backup copy)
- Spatial and temporal patterns of global burned area in response to anthropogenic and environmental factors: Reconstructing global fire history for the 20th and early 21st centuries, Yang et al 2014
- O mito do ano: "o desmatamento da Amazônia provocou a seca no Sudeste"
Deve-se distinguir claramente a diferença entre uso da terra e desmatamento. Todo desmatamento é uma forma de uso da terra, mas nem todo uso da terra é um desmatamento. Deve-se portanto, quantificar separadamente uso da terra e desmatamento. As áreas agrícolas (uso da terra) fora da região do domínìo da floresta tropical úmida que ocorre nas regiões de savana (cerrado, campos cerrados) dos estados periféricos da Amazônia Legal (Mato Grosso, Tocantins, Pará, Maranhão) não devem ser consideradas como áreas desmatadas e não o foram neste relatório. [..]
CONTRARY to widespread belief, evidence is mounting that pre-Columbian America was not a pristine wilderness inhabited by people who lived in such harmony with nature that they left it unmarked. Instead, many scientists now say, the original Americans powerfully transformed their landscape in ways both destructive and benign -- just like modern people.
[...] more extensive fires on the alluvial islands of the middle Rio Negro were those of the 1925/26 El Niño year, witnessed and poetically described by Marchesi (1975):Thunder and lightning appeared every day without rain. Then the great forest fires began. Flames crossed from one side of the river to the other... Dense smoke covered the entire region, eclipsing thesolar disk. It was night for us too on the upper Rio Negro where the fire had not yet arrived. Weasked ourselves if it weren’t the end of the world. Finally, in early April after 100 days of drought unlike any known before, a tempest struck.