- Recent studies from two long-running planted forest experiments in China and Panama find that increasing tree diversity in reforestation efforts can boost resilience in the face of climate change, among other benefits.
- Researchers elsewhere propose a “rewilding-inspired forestry” approach that aims to restore biodiversity, aid climate mitigation and bolster forest ecosystems — an approach that requires a significant shift from current forestry practices.
- However, scientists underline that while reforestation and forest rewilding can contribute to curbing climate change, they have their limits and must be combined with deep carbon emissions cuts and conservation of existing forests.
When it comes to reforestation, planting a diversity of tree species could have a plethora of positive effects on forest health and resilience, climate mitigation and biodiversity. That’s based on research from the world’s largest tree-planting experiment, in China, and the world’s longest-running tropical forest planting experiment, in Panama.
Florian Schnabel, lecturer and chair of silviculture at Freiburg University in Germany, and his team recently published two papers illustrating how planting diverse forests can buffer them against climate extremes and enhance carbon storage.
“The results of our research in Panama and in China really call for preserving and also planting diverse forests as a strategy under climate change,” he says.
Researchers with the BEF-China project planted multiple forests, ranging from just one tree species up to 24, then measured microclimate temperatures over six years.
They found that the more diverse the forest, the greater the “temperature buffering” effect during hot and cold peaks. The most diverse plantings, those with 24 species, reduced temperatures during peak midday summer heat by 4.4° Celsius (7.92° Fahrenheit) when compared to the project’s monoculture. That finding could have important consequences for biodiversity and forest functions, such as soil respiration, says Schnabel. “What was quite striking to me was how strong this [temperature buffering] effect actually was.”
While the paper’s findings are not groundbreaking, says Karen Holl, a professor of environmental studies at the University of California, Santa Cruz, the study effectively demonstrates the benefits of diverse tree species.
“People are making arguments for why we should plant more species of trees rather than monocultures, and this [new study’s results] just adds to the list of reasons that we should do that,” says Holl, who was not involved in the research.
Half a world away, in Panama, a 16-year-long study also led by Schnabel found that species-rich planted forests grow more stable over time. Increased tree diversity also leads to greater storage of carbon stocks and fluxes above ground. And, crucially, that result persisted during periods of drought and intense storms, says Schnabel — two weather extremes that are increasing with climate change.
Taken together, the two studies show that planting a rich array of species can “increase carbon storage, temperature buffering and forest ecosystem stability,” says Schnabel. There may also be economic implications: “We see clearly [that] higher wood production [occurs] in these species-rich forest.”
In his view, that is particularly important and relevant for large-scale forest restoration initiatives planned during the U.N. Decade on Ecosystem Restoration. “They really should focus on diverse planted forests,” he says.
Rewilding-inspired forestry
Rapidly escalating climate change threatens to upend forest carbon storage ability, with a recent paper warning that a range of natural and anthropogenic “disturbances” — including wildfires, disease, pests and deforestation — could endanger climate emission reduction targets.
Getting reforestation right is thus a crucial question. Many existing forest restoration projects promise to plant thousands, millions, and sometimes billions of trees. But experts warn that these efforts, if not thoroughly planned and monitored, can lead to a range of negative environmental and social consequences.
In another recent study, Lanhui Wang, a researcher with the Department of Physical Geography and Ecosystem Science at Lund University in Sweden, along with other team members, proposed a forest restoration solution: Rewilding-inspired forestry.
This methodology, he explains, “prioritizes restoring and relying on natural processes, such as trophic interactions, natural disturbances, and species dispersal, to create self-sustaining, biodiverse forest ecosystems.” This approach contrasts dramatically with “conventional forestry,” comprising short rotations, clear-cuts and monocultures that have high wood yields at the expense of ecological complexity and climate resilience.
Wang’s research team proposes 10 principles such as natural regeneration, reintroduction and recolonization of native forest species, and a marked change in management practices, such as selective logging. A rewilding approach “is necessary to address biodiversity loss, climate change, and habitat fragmentation by making forests more ecologically resilient and better able to store carbon and sustain wildlife,” Wang wrote in an email.
Schnabel’s forest diversity concept aligns to some degree with the proposed rewilding idea, as it is “restoring complexity, rather than simplifying forests, [and] yields substantial climate mitigation and biodiversity benefits,” according to Wang.
In Wang’s view, tropical countries in South America, Africa and Asia — with swaths of monoculture plantations or high levels of forest degradation — stand to benefit the most from forest rewilding, as it could bolster biodiversity hotspots, buffer microclimates, and provide additional resources and income for local communities.
Schnabel agrees, to an extent, that the rewilding-guided forestry approach could be effective, as it helps ensure that tree diversity is a crucial element in such projects. But he stresses that some of the components of the “rewilding-inspired forestry” approach as proposed by Wang’s team may be challenging to put into practice.
For instance, reintroducing large herbivores, one of the 10 proposed rewilding mechanisms, could be counterproductive to tree growth, as some animals feast on certain seedlings, while reintroducing large predators to control seed-eating wildlife is likely to face significant barriers, including human conflicts, particularly when restorations occur close to human populations, as they often do.
In forest landscapes where the aim is to restore natural dynamics, and where large predators and herbivores can be reintroduced with local community acceptance, forest rewilding has the potential to be a “very nice approach,” Schnabel says. “If you are diversifying such systems, you most likely create resilient feedbacks so that the systems can also respond to perturbations in ways we maybe cannot foresee.”
Holl says she agrees with many of the rewilding guidelines proposed by Wang’s team, but she underlines that there will always be trade-offs when conducting specific reforestation projects. A crucial part of any planning process is narrowing down exactly why you are planting trees, whether for carbon storage, biodiversity, or timber production. “We can’t do it all at once,” she says.
“If your goal is maximizing biodiversity, then reintroducing all the fauna and natural processes makes a lot of sense. If you’re trying to maximize timber production, it’s probably not the best thing to be doing,” Holl concludes.
Limits to forestry practices, diverse or otherwise
Moving toward greater tree diversity in reforestation and forestry could clearly come with climate and biodiversity benefits, but the new research also includes a sobering dose of reality: Forests cannot be relied upon to soak up the vast amount of emissions currently released by humanity, Schnabel stresses. His team notes that at the Panama site, it takes 11 hectares (27 acres) of diverse forest to absorb the equivalent CO2 emissions of just one airline flight from Frankfurt to Panama City.
Holl bluntly adds: “We’re not going to plant our way out of climate change.” Both scientists underscore another fact: While reforestation and rewilding are important in potentially curbing climate change, protecting existing forests is crucial.
“The message we want to bring is that, yes, forests can contribute to reducing carbon dioxide and thereby contribute to climate change mitigation,” Schnabel explains. And the most effective approach for doing so is to “focus on mixed species planted forest.”
However, he says, neither forest restoration or forest rewilding will “work if we continue to blow out as much carbon as we currently do.”
Banner image: An agamid lizard in a Chinese rainforest. Image by Rhett A. Butler/Mongabay.
How is conservation preparing for a much hotter world? Experts share
Citations:
Schnabel, F., Beugnon, R., Yang, B., Richter, R., Eisenhauer, N., Huang, Y., … Bruelheide, H. (2025), Tree diversity increases forest temperature buffering via enhancing canopy density and structural diversity. Ecology Letters, 28(3), e70096. doi:10.1111/ele.70096
Schnabel, F., Guillemot, J., Barry, K. E., Brunn, M., Cesarz, S., Eisenhauer, N., … Potvin, C. (2025). Tree diversity increases carbon stocks and fluxes above—but not belowground in a tropical forest experiment. Global Change Biology, 31(2), e70089. doi:10.1111/gcb.70089
Windisch, M. G., Humpenöder, F., Merfort, L., Bauer, N., Luderer, G., Dietrich, J. P., … Popp, A. (2025). Hedging our bet on forest permanence for the economic viability of climate targets. Nature Communications, 16(1). doi:10.1038/s41467-025-57607-x
Di Sacco, A., Hardwick, K. A., Blakesley, D., Brancalion, P. H., Breman, E., Cecilio Rebola, L., … Antonelli, A. (2021). Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits. Global Change Biology, 27(7), 1328-1348. doi:10.1111/gcb.15498
Holl, K. D., & Brancalion, P. H. (2022). Which of the plethora of tree-growing projects to support? One Earth, 5(5), 452-455. doi:10.1016/j.oneear.2022.04.001
Wang, L., Wei, F., Tagesson, T., Fang, Z., & Svenning, J. (2025). Transforming forest management through rewilding: Enhancing biodiversity, resilience, and biosphere sustainability under global change. One Earth, 8(3), 101195. doi:10.1016/j.oneear.2025.101195
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