Forest restoration is not a novel concept, however, advancements in science continue to refine and enhance its efficacy. The 1t.org US Community Collaborative hosted a webinar to dive into the evolving landscape of conservation and restoration, and review some of the emerging science that has built on past research in recent years.

Background Science:

The Nature Conservancy partnered with 15 other institutions to publish a study in 2017 highlighting the potential of natural climate solutions (NCS) to provide over one-third of the mitigation needed by 2030 to combat climate change. In addition to the carbon storage potential of nature, there are many additional benefits for biodiversity and habitat protection.

Further research by TNC was released in 2021 detailing an NCS hierarchy that serves as a comprehensive framework for prioritizing actions related to natural climate solutions (NCS), which are strategies involving the protection, management, and restoration of natural lands to mitigate climate change. While restoration has gained attention, we must consider protection and improved management alongside restoration efforts to maximize climate mitigation benefits.

Applying the hierarchy to forests:

• 1. Protection: Forest conservation that can prevent further deforestation and degradation of existing forest ecosystems is critical due to its high potential for carbon storage and sequestration. This prevents emissions from land conversion and maintains existing carbon stocks. Protecting forests also helps preserve biodiversity and maintains water quality.
• 2. Improved Management: The next priority is to improve the management of working forest lands. This involves practices that minimize emissions and enhance carbon sequestration while allowing for continued land use. This could include adopting sustainable logging practices, implementing agroforestry systems, and promoting land-use planning that balances conservation with economic activities.
• 3. Restoration: While restoration of ecosystems, including forests, offers substantial climate mitigation potential, it’s placed lower in the hierarchy due to higher costs and longer time horizons for realizing benefits. This may involve activities such as reforestation, afforestation, and natural forest regeneration.

The Global Opportunity

One of the most prominent breakthroughs demonstrating the potential of forest restoration came in 2015 from Thomas Crowther et al. through their research mapping tree density. They generated a map of global tree density that revealed what is going on below the canopy, showing patterns in tree numbers at scale and allowing researchers to estimate there are three trillion trees in the world. Expanding on this research, Jean-Francois Bastin et al. built a model to show where forests would naturally be in the absence of human activity and suggested that nearly a billion hectares of land are suitable for natural forest recovery.

The study estimated that the earth might have the capacity for a trillion new trees, which could sequester 205 gigatons of carbon.

This news quickly gained traction within scientific, media, and policy circles dedicated to addressing the climate crisis. Crowther describes the response as “bonkers.” While numerous initiatives aimed to safeguard forests were launched with noble intentions, some skeptics questioned the oversimplification. And this doubt may have been warranted. For some, the idea of ecological restoration became conflated with mass tree planting in the media, which is not an effective or science-based approach to restoration.

“Science isn’t just about having good ideas, it’s more about building consensus around those ideas so society can have the foothold to move forward.” – Dr. Thomas Crowther

To address the bonkers situation, scientists around the world dove deep into data and revisited those 2019 numbers to get a more comprehensive understanding of the forest restoration potential. With an incredible breadth of data and over 200 scientists, the Integrated Global Forest Assessment found that they were underestimating the potential of global forests.

Tools to Translate Science to Action

To effectively tackle the climate and biodiversity crisis, we must channel resources into translating ambitious goals into practical, on-the-ground strategies. Continued research is essential for pinpointing optimal reforestation sites and ensuring the effective implementation of nature-based solutions in the fight against climate change and biodiversity loss.

Dr. Susan Cook-Patton’s research at The Nature Conservancy illustrates how restoring forest cover in the United States can serve as a cost-effective climate solution. Her study identified diverse reforestation opportunities, including converting agricultural lands with poor soil conditions and frequently flooded areas into thriving forests.

By dissecting complex data and creating the Reforestation Hub, Cook-Patton’s research empowers stakeholders to explore tailored reforestation opportunities suited to their local contexts. Strategic investments in reforestation are crucial to maximizing climate benefits per dollar and acre.

Crowther highlighted another mapping tool for global restoration called Restor. This tool allows landowners to generate information that informs us of the state of the global movement. Organizations can map their sites and gain access to biodiversity, carbon, water and land-use change data sets instantly. This tool aims to empower local landowners, farmers, and indigenous communities who are stewards of nature.

Albedo’s Impact on the Carbon Potential of Reforestation

Cook-Patton has a new paper recently published on the concept of albedo, which refers to how much sunlight is absorbed versus reflected by the Earth’s surface. Forests tend to have a darker surface, which can cause warming compared to lighter surfaces like grasslands. The research found that while some areas experience a net cooling effect from reforestation due to increased carbon storage outweighing the albedo effect, others may experience a net warming effect.

By analyzing various land cover transitions and their impact on albedo and carbon storage, the research provides insights into where reforestation efforts can have the most significant climate benefits. Using mapping techniques, the team developed maps showing the net climate impact of reforestation across different regions. These maps reveal that while certain areas may benefit from reforestation in terms of carbon storage, others may not, highlighting the importance of strategic planning.

However, carbon sequestration is not the only reason to conserve and restore forests. Cook-Patton highlighted the importance of biodiversity and its crucial role in sustaining life on the planet, including humans, and climate is just one piece of the puzzle. The primary focus of restoration should be on bringing back nature, which encompasses the well-being of people and the entire ecosystem.

Biodiversity and Bioacoustics Monitoring in Costa Rica

The Crowther Lab team is continuing to demonstrates that restoration isn’t solely about planting trees but involves revitalizing ecological integrity, including restoring critical components like microbes and animals. Crowther shared insights from a new study indicating that healthy ecosystems recover faster and highlighted the vital role of large animals in carbon capture.

In Costa Rica, Giacomo Delgado and teams from Costa Rican universities are conducting an extensive ecoacoustic survey of the country’s forests. By positioning microphones at over 600 sites, they aim to assess ecosystem health and biodiversity by analyzing the soundscapes. This survey, among the largest of its kind, utilizes audio recorders and advanced machine-learning techniques to monitor ecosystem changes in real time.

The project compares soundscapes from regenerating forests with those from intact ones, providing insights into the effectiveness of large-scale forest restoration efforts. The survey could revolutionize biodiversity monitoring globally, potentially leading to a network of acoustic sensors monitoring ecosystems worldwide. Preliminary results suggest that restored forests resemble intact ones more closely, indicating successful large-scale forest restoration can combat biodiversity loss.

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Conservation and restoration, done effectively and guided by science, are both effective strategies that we need to act on to address the climate and biodiversity crises. However, while deploying viable climate solutions is crucial, it’s also essential to focus on reducing fossil fuel emissions, which is paramount. By embracing science-based approaches and collaborating across sectors, we can harness the full potential of nature to address the climate and biodiversity crises.

Review the webinar recording below

Speakers

Dr. Thomas Crowther | Assistant Professor, Department of Environmental Systems Science, ETH Zürich

Thomas Crowther is an assistant professor in the Department of Environmental Systems Science, where he founded Crowther Lab. Crowther serves as co-chair of the advisory board of the UN Decade on Ecosystem Restoration. After completing his PhD at Cardiff University, Crowther received a postdoctoral fellowship from the Yale Climate and Energy Institute.

Dr. Susan Cook-Patton | Senior Forest Restoration Scientist, The Nature Conservancy

Susan Cook-Patton is part of the Natural Climate Solutions Science Team at The Nature Conservancy. She works to quantify the climate mitigation potential of reforestation and other natural climate solutions and infuse the best-available science into policy decisions. Before joining TNC, she was a policy fellow at the US Forest Service and a research fellow at the Smithsonian Institution. Susan holds a PhD in Community Ecology from Cornell University, and bachelor degrees in Biology, Psychology and English from Indiana University.