Fires threaten forests’ ability to store CO2


Research, recently published in the scientific journal Nature Ecology and Evolution, indicates that frequent fires threaten ecosystems and the ability of forests to store carbon dioxide. According to the results released, some regions do not recover from repetitive fires, that is, those that occur frequently over the years.

The analysis, led by researcher Adam Pellegrini of the Department of Plant Sciences at the University of Cambridge, took into account evidence collected over decades. Through the vast database, the team mapped the damage suffered by regions with annual fires and changes over 50 years. Among them, there is an alarming reduction in the number of trees, which reached 72%. In regions with less frequent fires, that number was 63%.

Reduction in CO2 storage

As a consequence of this drastic decrease in the green area, there is a reduction in the carbon storage capacity of the forests, already mentioned above. In this scenario, the immediate solution is to plant these lost trees. However, Pellegrini warns that there are some factors to consider before taking action.

Although the wetter regions favor the growth of trees, they are more prone to fires (as well as drier regions). The zones that offer greater security and resistance, highlights the researcher, are those with moderate temperatures.

“Planting trees in areas where trees grow quickly is widely promoted as a way to mitigate climate change. But to be sustainable, the plans must consider the possibility of changes in the frequency and intensity of the fire in the long term ”, pondered Pellegrini.

Fires reduce soil health

This is not the first study to address the long-term effects of forest fires. Previous analyzes have already revealed that such events reduce the level of nutrients, including nitrogen, in the soil. Although it looks negative, research published in the journal Nature Ecology and Evolution points out that this may favor trees with slower growth – capable of surviving in poor soils.

However, these trees make the recovery of forests more difficult, while retaining the nutrients they have, preventing the soil from enriching and allowing new seedlings to grow after an intense fire.

Increased carbon in the atmosphere

Along with the increasing degradation of ecosystems, researchers have registered an increase in the amount of carbon dioxide in the atmosphere, driven by fires – which destroy 5% of the Earth’s surface each year, releasing CO2 equivalent to 20% of annual fossil fuel emissions.

This is a relatively new problem. In the past, most of the gas released by the fires was recaptured as soon as the ecosystems were recovered. However, with the intensification of climate change, events have become less widely spaced. As an example, we mention the Brazilian scenario in 2020, which presented the largest number of outbreaks of burns of the decade, according to data from the National Institute for Space Research (Inpe).

“The species of trees that are more tolerant to fire generally grow more slowly, reducing the productivity of the forest. As climate change causes forest fires to become more intense and droughts more severe, the forest’s ability to recover is impaired – reducing its carbon storage capacity ”, explains the researcher.

The study, which is funded by the United States National Institute of Food and Agriculture and the Gordon and Betty More Foundation, is the broadest of its kind with data from 29 sites from different ecosystems, divided between Africa, Australia, Europe and South America. North.


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