- Research from Brazil shows that tree species adapted to extreme heat may be key to reforesting areas affected by fires.
- The ongoing research focuses on plants native to the Cerrado savanna, a biome where fire is a natural mechanism for vegetation regeneration and seeds can germinate after the land is burned.
- The findings have practical implications for the Cerrado, which is the most burning-prone biome in Brazil, with the risk of fire exacerbated by agriculture.
- Proponents say restoration strategies that include heat-resistant species can minimize the impacts and prepare the restoration site for other species to take root.
Fire-resistant seeds offer promise, at a low cost, for restoring areas devastated by burning in Brazil’s Cerrado savanna, a project by biologist Giovana Cavenaghi Guimarães shows.
Guimarães, a doctoral candidate at São Paulo State University (UNESP), focused on five species of Cerrado-native seeds, including jatobá (Hymenaea courbaril), amendoim-bravo (Pterogyne nitens), mulungu (Erythrina mulungu) and canafístula (Peltophorum dubium). All are naturally adapted to extreme heat.
According to Guimarães, these plants can survive in adverse conditions such as the high temperatures caused by wildfires, which makes their seeds ideal for environmental recovery after such events. The species also have a greater germination capacity: on average, 99% of seeds develop into trees.
“The idea of the study is to understand these species’ physical dormancy, which allows them to survive in conditions of high temperature and fire,” Guimarães told Mongabay. “When these seeds are in the soil, even if the fire destroys those that have already germinated, they resist the high temperatures and germinate, even after the fire.”
Physical dormancy is a natural process in some species, which prevents seed germination until conditions are right. It’s considered a survival mechanism. In the case of the plants studied by Guimarães, exposure to high temperatures can break this physical dormancy by causing cracks in the husk, or integument, thus allowing water to enter and germination to occur.
A solution to a growing problem
According to Guimarães, planting seeds of these native fire-resistant species can be a solution to recover large areas destroyed by wildfires, especially in the Cerrado, the Brazilian biome that burns the most. Data from INPE, Brazil’s national space agency, showed 46.8% of all fire outbreaks recorded in the country in the first 10 months of the year — almost 50,000 — occurred in the Cerrado.
Fire is a natural phenomenon in the Cerrado, and has historically played a key role in vegetation regeneration in the biome. That’s why many of the native plant species have evolved to resist heat. But the current increase in fires in the biome is driven by agriculture.
Elisangela Ronconi Rodrigues, a plant biologist and professor at United Metropolitan Colleges (FMU) in São Paulo, who isn’t involved in Guimarães’s ongoing research, agreed that restoration with fire-resistant seeds could work in the Cerrado, but not necessarily in other biomes.
“The first step in restoration is to assess the area and understand its particularities,” she said. “Physical dormancy occurs in seeds of some species, but not in all of them. Thus, the method is interesting for areas where these seeds have a greater chance of germinating, such as the Cerrado or hot places with prolonged droughts.”
Kenny Tanizaki Fonseca, a professor at Fluminense Federal University (UFF) in Rio de Janeiro state and a forest and reforestation researcher, said the species studied hold strong potential for reforestation.
“This method of using seeds with physical dormancy and a lower chance of mortality in burned areas is an interesting and easy-to-implement strategy,” he said.
Another key point about reforestation, according to the experts, is that the area to be restored should receive a wide variety of species to guarantee biodiversity and increase the likelihood of ecological restoration success.
“A sick area affected by fire can recover naturally,” said Rafael Bitante Fernandes, forest restoration manager at SOS Mata Atlântica, a conservation NGO that focuses on the Atlantic Forest, another heavily deforested biome. “But of course, if this happens frequently, it is important to help nature by carrying out restoration with the greatest possible variety of species, in order to try to protect the area. Since each species has its own peculiarities, the more diversity we have in a place, the greater the chance of success in this restoration.”
The ideal planting method
Guimarães’s research is still underway, and her thesis is expected to be published in the coming months. But she already points to pathways for a reforestation strategy based on the seeds she’s been studying.
She said direct seeding is the best planting method because it’s cheaper. It involves placing the seeds directly into the soil, manually or mechanically, depending on the size of the area. This technique doesn’t disturb the soil; only a small hole is opened where the seed is planted.
“With direct seeding, ecological restoration will occur naturally. Therefore, we recommend doing it with these fire-resistant seeds so that even if the area is burned, they will resist and germinate,” Guimarães said.
The other reforestation method commonly used in the country is to grow seeds in a nursery and then plant the seedlings, which is more expensive.
“This process of creating the seedlings and then planting them in devastated areas is more expensive because we need labor to cultivate the seedlings and then to plant them,” Guimarães said. “Several Brazilian research studies have already proven that direct planting is an inexpensive way with good results. This technique is widely used in agriculture, and we can also employ it in ecological restoration.”
She continues to study seeds from so-called pioneer plants, those that are the first to start growing in a degraded environment. Because they’re more resistant to adverse conditions, they germinate and protect the soil so that other species can emerge or be planted in the area at a later time.
Banner image of mulungu seeds (Erythrina mulungu), by CostaPPPR via Wikimedia Commons (CC BY-SA 4.0).
This story was first published here in Portuguese on Nov. 13, 2025.
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