Forest restoration: study shows need to invest in "high quality" projects with more than 10 species planted

An analysis of over 200 tree-planting projects for carbon credit generation around the world has shown that the vast majority have low biodiversity. Only 12% of them plant ten or more native species, while 32% use exclusively exotic species.

Too many restoration projects still feature low diversity of non-native species

The study, carried out by the Social Carbon Foundation, an English NGO, in collaboration with the Eco+ Foundation, funded by the German chemical company Basf, highlights the challenges associated with restoring ecosystems and combating climate change through reforestation and the restoration of degraded areas. These projects, registered internationally since 1999, aim to increase carbon stocks in biomass and soil by planting trees, which capture CO2.

"The analysis identified the need to review the type of ARR project eligible for carbon certification," says the document. "A significant proportion of projects plant non-native species, use logging and do not monitor associated benefits. These projects offer limited benefits for biodiversity."

However, the analysis reveals that many projects prioritize the planting of non-native species, resort to logging and neglect to monitor additional benefits, thus limiting biodiversity benefits. Projects have been categorized according to whether they use native, mixed or exotic species, each with different impacts on the ecosystem.

In the first case, a variety of species naturally present in the area are planted, maximizing restoration potential. Mixed species projects often combine trees with agricultural crops. Exotic species projects plant non-native species for commercial purposes, including monocultures.

"We've noticed that, although the number of projects of this type has increased in recent years, this expansion may have come at the expense of a lesser wealth of biodiversity," says Tiago Egydio, biologist and director of the Eco+ Foundation.

"If you're undertaking a forest restoration action, you can certainly use non-native species in your plantation, but it's necessary to choose very precisely which species and how much space it will occupy over a given period," he explains.

"It may strategically shade an area, but after a cycle of five to ten years, it fulfills its function and the slightly slower-growing species that were underneath begin to gain strength and structure themselves within a long-term native forest ecosystem."

A recurring observation in the study is the predominance of projects that favor the cultivation of fast-growing species such as eucalyptus and teak. Although these species are native to regions such as Oceania, their use in projects can give the impression of a reforestation and restoration approach focused on local species. However, the report often reveals that they are in fact commercial plantations intended for logging.

The analysis also shows that only 18% of projects claiming to use native species actually plant ten or more species, while 57% plant only four or fewer. According to the study's authors, an ideal reforestation or restoration project should incorporate more than ten native species in at least half of all cases.

The researchers point out that the results indicate a flaw in the current market for offsetting greenhouse gas emissions.

"Projects may select native species based on their carbon capture potential and not design ARR projects from an ecosystem health perspective."

Divaldo Rezende, agronomist and President of Social Carbon in Brazil, explains that, in practice, carbon credits from more complex, restoration-oriented projects can be more expensive, but are also more reliable in terms of their effectiveness and offer benefits beyond CO2 capture.

"Today, the main buyers of carbon credits don't want those from a monoculture, because monoculture can generate additional risks, including in terms of reputation," he asserts. "On the other hand, when you have projects to restore or use native species, you create or strengthen a specific ecosystem, enhancing biodiversity, water and even social inclusion."

He also points out that the benefits of the bioeconomy are associated precisely with areas planted with native species, which can provide, for example, bioactive compounds, vegetable oils and other value-added products that go beyond logging.

The report shows that logging characterizes 48% of the projects analyzed, a practice particularly widespread (90%) in projects based on exotic species, often linked to the traditional forestry industry. In contrast, only 15% of projects using native species resort to this practice, focusing instead on increasing biodiversity and sometimes including activities such as fruit picking.

In terms of geographical distribution, Asia and Latin America are home to the majority of projects, with China in the lead, accounting for 57 of the cases studied. Overall, 44% of projects focus on native species, followed by 32% for exotic species.

However, the situation varies significantly outside China, where native species projects drop to 25%, while exotic and mixed species projects account for 42% and 33% respectively.

In Brazil, an analysis of 12 projects reveals an average of over 24 species per project, although this average is influenced by a project in São Paulo that grows 150 different species.

Urgent need to scale up using a diverse mix of native species

The study also highlights the crucial importance of deploying Regeneration Assisted by Indigenous Species (RAAS) projects worldwide to combat environmental degradation, climate change and biodiversity loss.

"It is essential that Regeneration Assisted by Indigenous Species (RAAS) projects are implemented on a large scale worldwide to address environmental degradation, climate change and biodiversity loss. At the heart of this approach is the deliberate choice to use a diverse mix of native species."

According to the researchers, the key to these projects lies in the strategic use of a variety of indigenous species. These species, deeply integrated into their local ecosystems, make important contributions to tree planting, reforestation and revegetation initiatives. They are adapted to the specific climatic conditions and soils of their region, and maintain complex ecological interactions, facilitating the creation of resilient and prosperous ecosystems. It is advisable to include at least ten native species in such projects, and many more, to faithfully recreate natural habitats and maximize biodiversity benefits.

Adopting a wide diversity of native species helps to increase biodiversity, by encouraging harmonious coexistence between different plant and animal species.

This diversity contributes to ecological balance and resilience, offering greater resilience to environmental challenges. In addition, native species generally have better resistance to pests and diseases, reducing the need for external chemicals such as pesticides and ensuring more sustainable carbon sequestration.

The study also calls for the promotion of natural regeneration as the preferred restoration method worldwide, particularly in tropical regions. Recognized for its efficiency and cost-effectiveness, natural regeneration stands out as an optimal strategy for forest and landscape restoration over large areas, compared with more active restoration approaches.

Nevertheless, projects incorporating more than ten native species are generally on a smaller scale (less than 1,000 hectares), which makes sense given the higher costs and the need for a larger seed supply, underlining the imperative of solutions that can be deployed on a larger scale. For this reason, there is an urgent need to invest in scientific research and technology, in order to make large-scale projects (over 1,000 hectares) possible.

It should be noted that this study also examined emission removals from Reforestation and Ecosystem Restoration (RER) projects by region, country, RER approach and biodiversity. The analysis revealed that, on average, the estimated annual emissions removals (ER) per hectare for exotic ARR projects were 31% lower than for ARR projects with native species. This result is understandable, especially given that 90% of exotic projects involve logging, compared with 15% for native projects. Another study found that a project comprising at least four species sequesters 70% more carbon than a monoculture. The study also investigated whether the higher number of species planted appeared to be negatively correlated with annual ER per hectare. This is probably due to the fact that projects planting fewer species deliberately chose fast-growing species with greater carbon capture potential. Conversely, projects focusing on a greater diversity of species prioritize biodiversity and the reproduction of native ecosystems over carbon. But is this really justified? Taking a step back, prioritizing biodiversity and ecosystem reproduction over carbon capture raises questions about the over-valuation of low-biodiversity projects.

MORFO is one of the existing solutions for large-scale restoration

At MORFO, we discovered this study with great interest. In response to these challenges, MORFO is emerging as a promising solution. Our innovative approach, capitalizing on advances in science and technology, aims to make RAEF projects with a high diversity of native species not only viable but also scalable, even beyond 1,000 hectares. We overcome the traditional barriers of seed cost and availability, paving the way for more ambitious forest restoration initiatives with greater environmental impact.

To consult the study, click here.

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