Few Tree Species Drive Amazon Forest Recovery, Study Finds

Researchers examining 102 plots under natural regeneration across four municipalities in Pará state—Bragantina, Marabá, Paragominas, and Santarém—found that a remarkably short list of species drives the recovery of deforested lands. Among these hyperdominant trees 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.

Decoding Secondary Forest Dynamics in Pará State

The Brazilian Amazon features more than 140,000 square kilometers (around 57,000 square miles) of secondary forests—regrowing areas previously deforested, known as secondary forests, in many cases abandoned after being used for cattle ranching. According to Fernando Elias, a researcher in Pará’s Emílio Goeldi Museum and the coordinator of the study, most of this land possesses the potential to recover naturally, without the need to plant a single seed. These areas are already restoring [ecological] services and biodiversity, Fernando Elias told Mongabay. That is why it is so important to understand how these forests behave.

Understanding these trajectories gives conservationists parameters to evaluate restoration success in a given area and the potential need for interventions. 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. 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.

The Critical Succession from Pioneer Species to Strong Wood

When a forest starts to reflourish, the first trees to thrive are the so-called pioneers, which can resist direct sunlight. However, these early arrivals present inherent limitations for carbon storage as they have less dense, white wood and are unable to store much carbon. Since it grows so fast, it has a low wood density, said Fernando Elias.

Experts warn that forests need a robust succession of stronger trees to avoid ecological decline over time.

Meeting Brazil’s 2030 Restoration Targets and Carbon Markets

The findings offer practical frameworks to guide assisted restoration and enrichment strategies. This data directly supports Brazil’s National Plan for the Recovery of Native Vegetation (Planaveg), which 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.

State-level ambitions mirror the federal push. Pará state, for example, has committed to recovering 7.41 million hectares (18.31 million acres) by 2036, according to the study. Meanwhile, private companies such as Mombak, re.green and Biomas are developing large restoration projects in the Amazon to generate carbon credits.

Parallel Findings on Tree Diversity and Temperature Buffering

The ecological value of species richness extends far beyond carbon stocks and biomass. Research led by researchers from the German Centre for Integrative Biodiversity Research (iDiv), Leipzig University, and the Martin Luther University Halle-Wittenberg (MLU) published in the journal Ecology Letters demonstrates that a forest with high tree-species diversity is better at buffering heat peaks in summer and cold peaks in winter than a forest with fewer tree species.

Conducted in a large-scale planted forest experiment in China—the largest planted tree diversity experiment worldwide, known as the BEF-China experiment where several hundred thousand trees were planted into plots consisting of 1, 2, 4, 8, 16, or 24 different tree species—the study involved forest temperature measurements conducted over six years (2015-2020) by a joint Sino-German international research training group. The results showed that cooling was up to 4.4°C stronger in experimental plots with 24 species compared to plots with just a single species during midday heat in summer. Species-rich forests were also better at increasing temperatures during cold hours at nighttime and during winter. Experimental plots with many tree species showed both a higher canopy density (more leaf area per ground area) and a higher structural diversity (for instance, a higher variety of smaller and larger trees), which enhanced temperature buffering by probably reducing the mixing of air masses. A buffered microclimate creates more favorable conditions for ecosystems and protects the services they offer, says co-first author Dr Rémy Beugnon from iDiv, Leipzig University, and the Centre d’Ecologie Fonctionnelle et Evolutive. Under a buffered climate, forests are likely to grow and regenerate more effectively, while soils function better, supporting greater biodiversity, improving nutrient cycles, and increasing carbon storage.