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Study: A chimney in an Amazon wetland destroys 27% of trees in 3 years

Publicado em 16 agosto 2021

Por tech4u

According to a cutting-edge study that measured the effects of an in situ fire site, a forest burned in a wetland loses on average 27. 3% of the density of its stems. The destruction basically affects small and medium-sized trees. The loss of biomass (carbon stored) in the 3 years following a chimney, the place reaches 12. 8%. Mortality is worse in the first two years and is giving way to the expansion of local herbaceous bamboo species.

The Amazon corresponds to 5. 9% of Brazil, with a territory of five million km², 77 five municipalities, 67% of the world’s rainforest, a third of its trees and 20% of its new water.

It is also the Brazilian biome with the maximum year of chimneys since the beginning of the records, according to the National Institute for Space Research (INPE). In 2020, INPE recorded 103,161 chimneys, the highest number since 2017 (107,439) and the 3rd. in the decade. The biggest moment occurred in 2015 (106,438). Inpe’s forest chimney statistics are summarized here.

The 2015 fires, aggravated by excessive drought related to El Niño, were the subject of a study funded by the São Paulo Research Foundation, FAPESP through two projects. of the Royal Society B: Biological Sciences.

The examination was conducted by Luiz Eduardo Oliveira e Cruz de Aragão, who heads the Earth Observation and Geoinformatics Division of INPE (DIOTG).

“Studying how forests respond to the chimney in the long run is one of the frontiers of wisdom about how the Amazon works. It is vital to our ability to design the long-term interactions of biome and climate, and to provide knowledge to Brazil to report emissions and carbon removal more particularly in the context of policies to decrease emissions from deforestation and forest degradation [REDD], which can generate monetary benefits for the country. ” said Aragão.

The researchers analyzed burned and unskilled spaces after the fires that hit the Northern Purús and Madeira (central Amazon) rivers and conducted annual surveys to track biomass replacement demographic points over the next 3 years.

The territory is located in the commune of Autazes, about 90 km southeast of Manaus, near the BR-319 motorway. The researchers measured trees with a diameter of 10 cm or more and estimated the extent to which stem expansion and tree mortality were influenced by chimney intensity (represented by the height of the charred trunk, an indicator of how long the trunk of a tree is exposed to flames and the maximum temperatures of a chimney) and the morphology of the tree (length and density of wood).

Most of the fieldwork was done through Aline Pontes-Lopes, PhD student, CANDIDATE for INPE, and Camila Silva, researcher at the Amazon Institute for Environmental Research (IPAM), respectively the first and last author of the article.

“Field knowledge is very valuable. The study included several censuses of the same burned area, a rare type of data for the Amazon. In particular, the box’s knowledge is scarce about the mortality, expansion and local dynamics of trees in tropical forest spaces in general. Examine also looked at the effects of chimney on the wetter parts of the forest, where it is unusual. There has been a lot of new wisdom about those spaces,” said Ricardo Dal’Agnol, INPE researcher and co-author of the paper.

Dal’Agnol, who is supported by FAPESP through a postdoctoral fellowship, participated in a study published in January that indicates that water stress, soil fertility and anthropogenic forest degradation create gaps in the Amazon rainforest and influence tree mortality more than any other factor.


“In burned areas, we have noticed that seedlings, small trees and trees are the first to die, clearing enough of the undergrowth to allow us to cross the forest and establish forest plots in 2015. Small and medium-sized trees died more often in two. at age 3,” said Pontes-lopes. The lower floor is the layer of trees and shrubs under the canopy but above the forest floor.

Another vital point, he added, is the effect of the chimney on biomass. According to the study, biomass remained solid over the three years in unskilled plots, but decreased by up to 12. 8% in burned areas.

The effect was especially severe on lianas, which lost 38. 6% of their american and 38. 1% of their biomass. Tree loss was 28% for individual trees and 12. 1% for biomass; for palm trees, the loss was 14. 6% for Americans and 27. 2% for biomass. The same comparisons for un burned plots showed much smaller losses or no significant change.

Growth measurements and comparisons through scientists between burned and unskilled spaces showed that trees with low wood density grew faster in burned spaces over a three-year era and that giant trees stored more carbon in burned spaces. However, the faster expansion of these two categories of trees resulted in an accumulation of total forest biomass or timber production, either of which was surpassed by tree mortality from chimneys.

According to Pontes-Lopes, other teams use the knowledge gathered from at least 4 studies. The knowledge was standardized and published on ForestPlots. net, an online page for researchers, forest scientists and forest communities to know the percentage that will measure, monitor and perceive the world’s forests, that is, in the tropics.


According to the researchers, continuous monitoring of spaces affected by chimneys in normal periods (annual or semi-annual) is vital to our understanding of carbon emissions and absorption, the time it takes the forest to recover to a pre-chimney state, and the disruption of carbon dynamics due to tree mortality due to more droughts and chimney events Future studies deserve to focus on the Long-term follow-up after chimneys to determine if delayed mortality from tall trees is occurring on a significant scale in the Amazon. Conclude.

It is estimated that fires in the Amazon are responsible for more than 50 percent of global greenhouse fuel emissions due to land-use change. These fuels, in specific carbon dioxide (CO2), contribute to the average temperature increase consistent with an increase. it may succeed at 1. 5°C above pre-industrial grades until 2050 if temporary effective measures are not taken to mitigate global warming.

However, the long-term effect on fires in the Amazon is not sufficiently quantified. An article published last year with Silva as the first writer showed that more than 70% of gross wildfire emissions over a 30-year era were due to tree mortality and decomposition (as opposed to combustion). These emissions were only partially offset through the expansion of forests during the same time. The study also found that net annual emissions peaked 4 years after the wildfires.

Deforestation and forest degradation, along with climate change, are compromising forest carbon stocks. Plant photosynthesis converts mild CO2 into energy, reducing the amount of CO2 in the atmosphere. Carbon remains in biomass until plants burn or die and decompose.

“Without land-use regulations, the Brazilian government’s current goal of paving BR-319 will increase deforestation in the Purús-Madeira region, expanding ignition resources and the related threat of large-scale logging,” the authors warn.

They presented two projects for long-term decision-making to avoid large-scale wildfire sites in the Amazon: mapping the hazards of wildfire sites and mapping of possible effects of fire sites based on morphological characteristics of plants. the progression of these projects.

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