Key tree species boost Amazon forest restoration, new study shows

A study in Global Change Biology shows that just 15 to 25 tree species make up nearly half of the trees and carbon stocks in regrowing Amazon forests.While pioneer species grow quickly, experts warn that forests need a robust succession of stronger trees to avoid ecological decline over time.Understanding these forest dynamics may help Brazil meet its international pledge to restore 12 million hectares (30 million acres) of forest by 2030. A few tree species are key to restoring biodiversity and carbon storage in deforested areas of the Brazilian Amazon, suggests an article published in June in Global Change Biology. Researchers examined 102 plots under natural regeneration in four municipalities in Pará state — Bragantina, Marabá, Paragominas and Santarém — and concluded that a range of 15 to 25 species accounted for nearly half of the trees present and half of the plots’ carbon stocks. ​Among these species are the embaúba (Cecropia palmata), the tatapiririca (Tapirira guianensis), the ingá-vermelho (Inga alba), and the araticum-bravo (Annona exsucca). ​This relatively short list of hyperdominant species could “guide assisted restoration and enrichment strategies” in the Amazon, the researchers said, and help Brazil meet the goal of restoring 12 million hectares (30 million acres) of forests by 2030, an area roughly the size of North Korea. ​“These areas are already restoring [ecological] services and biodiversity,” Fernando Elias, a researcher in Pará’s Emílio Goeldi Museum and the coordinator of the study, told Mongabay. “That is why it is so important to understand how these forests behave.” According to Elias, the Brazilian Amazon has more than 140,000 square kilometers (around 57,000 square miles) of regrowing forests in areas previously deforested, known as secondary forests. In many cases, these lands have been abandoned after being used for cattle ranching. ​Most of it has the potential to recover naturally, without the need to plant a single seed. Close monitoring, however, is necessary to control fires, cattle ranching and land grabbers and to assess whether the forest is properly recovering. ​“You continue to monitor the area to determine whether it is actually on a path toward restoration or whether it will end up with extremely poor ground cover in terms of biodiversity,” Beto Mesquita, a forest engineer and the director of sustainable landscapes at the NGO Conservation International, told Mongabay. Much of the secondary forests in the Brazilian Amazon are located in areas previously deforested for cattle ranching. Image courtesy of Bruno Kelly for The Intercept Brasil. ​By describing the expected trajectory of secondary forests, researchers like Elias help establish parameters for evaluating the success of restoration in a given area and the potential need for interventions. “At some point, for example, I may need to apply some kind of fertilizer to promote the growth of species that are less well-adapted to those soil conditions,” Mesquita adds. ​Brazil’s National Plan for the Recovery of Native Vegetation (Planaveg) includes awarding concessions for public lands, such as conservation areas, to private companies that commit to restoring the vegetation. In exchange, they can sell the carbon credits generated in those areas. Some Amazonian states have launched their own restoration initiatives. Pará state, for example, has committed to recovering 7.41 million hectares (18.31 million acres) by 2036, according to the study. Private companies such as Mombak, re.green and Biomas are developing large restoration projects in the Amazon to generate carbon credits. ​A little help for nature ​Once a forest starts to reflourish, the first trees to thrive are the so-called pioneers, which can resist direct sunlight. These species have less dense, white wood and are unable to store much carbon. “Since it grows so fast, it has a low wood density,” said Elias, who had support from the Serrapilheira Institute to conduct his research. “Strong wood takes time to grow.” ​As the recovery process evolves, pioneers should be replaced by more resistant trees. “Pioneers live for 15 or 20 years, and then they naturally die off,” said Mesquita. “And if you don’t have an established, robust succession system, you may see a decline in the forest and disrupt the restoration process.” ​Extremely degraded areas may need some help in this process, such as soil enrichment and the planting of seeds and seedlings. Scientists are developing new methods to meet the growing forest restoration market, including using drones to spread seeds in remote areas. ​Researchers from the universities of São Paulo, Campinas and São Carlos, and from the restoration company re.green, have tested drones in two degraded areas in the state of Bahia, in the Atlantic Forest. Companies like Mombak invest in gear and technology to accelerate forest restoration and carbon sequestration in the Amazon. Image by Raimundo Paccó/Mongabay. Their conclusions, published in August in the journal Ecological Engineering, show that drones reduced the costs and increased the effectiveness of restoration, especially in sloping areas. “[B]ecause these environments are typically difficult to access and manage, aerial seeding offers a major operational advantage by reducing labor demands and enabling large-scale restoration,” the authors wrote. ​The researchers also experimented with seeds encapsulated in a cassava-starch mixture to provide a nutrient boost and protect seeds from predation and drying out. Despite emerging more rapidly, seedlings from encapsulated seeds had a higher mortality rate. “Bare seeds outperformed encapsulated seeds in establishment, cost-effectiveness, and operational efficiency,” the researchers said. ​Despite acknowledging the importance of studying secondary forests, Mesquita said that researchers should offer more details about their study areas. The term “secondary forests”, he explained, is used both for a plot where the forest is regenerating after being completely cleared and for a standing forest subjected to selective logging and sporadic fires. ​“This makes a big difference in restoration,” he said. “The natural regeneration of an area that has been completely altered by human activity tends to have lower species diversity and abundance than that of a remnant area, even if the latter is heavily degraded.” Banner image: Researchers analyzed secondary forests in four municipalities in Pará state. Image courtesy of LEAF-MPEG/Centro Capoeira. New studies portray Amazon as surprisingly resilient, but tipping point looms Citations: Elias, F., Ferreira, J., Berenguer, E., Do Nascimento, R. O., Miranda, L., Silvério, D. V., … Barlow, J. (2025). Hyperdominance and rarity in Amazonian secondary forests. Global Change Biology, 32(6), e70970. doi:10.1101/2025.11.25.690408 Campanharo, Í. F., Rodrigues, R. R., Brancalion, P. H., Santos, J. P., Bringas, G. P., & Molin, P. G. (2026). Assessing drone-based direct seeding with bare and encapsulated seeds for enriching degraded tropical forest fragments. Ecological Engineering, 233, 108146. doi:10.1016/j.ecoleng.2026.108146 FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page. Credits Topics