May 31, 2021
Last summer, Science published a controversial study on the potential of planting trees to combat the effects of climate change. The report found that we could increase existing forests—without impacting existing cities or agriculture—by more than 25 percent around the world. The resulting 0.9 billion hectares of new trees could absorb 25 percent of our current carbon dioxide emissions, returning us to levels from nearly a century ago.
These staggering numbers proved to be a bit of an overpromise, as the team later published a correction, acknowledging that forest management is not a silver bullet solution, and noting that suitable land for planting trees will shrink as global temperatures continue to rise.
While the climate crisis undoubtedly requires a more multifaceted approach, scientists agree planting trees remains an affordable and promising strategy for mitigating climate change. However, not every tree planting project is intended to offset carbon. For organizations interested in reducing their carbon footprint through tree planting, it’s helpful to understand the difference between investing in planting trees and investing in verified forestry projects.
Carbon dioxide accounts for the largest percentage of greenhouse gases, which contribute to climate change by trapping heat and warming the planet. During photosynthesis, a tree absorbs carbon dioxide from the air, using it to produce carbohydrates as food.
All plants remove carbon to some degree. But woody perennials, such as trees, are particularly effective as they can store carbon long-term in the form of cellulose (wood) for hundreds of years. As trees grow, their roots also help store carbon in the soil. According to the USDA Forest Service, American forests and harvested wood currently absorb more than 14 percent of the United States’ carbon emissions every year.
While trees mainly pull carbon from the atmosphere, forests also release carbon dioxide as trees die and decompose. Responsible forest management includes monitoring this natural cycle to enhance carbon capture.
While all trees absorb carbon, not every tree planting initiative offers carbon offsets, which are credits that companies or individuals can receive to compensate their carbon footprint. Planting trees for carbon sequestration requires an in-depth verification process to ensure the project is contributing to the health of the planet.
Third-party verification services use a standard methodology to evaluate the emissions impact of planting trees, considering aspects such as:
Verified tree planting projects typically fall into two major categories: reforestation and afforestation. Reforestation projects restore trees and promote regrowth in existing forests; while afforestation projects plant trees where little to no forest previously existed.
Non-verified tree planting projects may help mitigate the effects of climate change, but unlike verified reforestation or afforestation projects, they are not designed for carbon sequestration.
For example, Eden Reforestation Projects has planted more than 583 million trees around the world since 2005, employing people to restore and protect forests on a massive scale. Communities suffering from deforestation are often living in extreme poverty, and Eden aims to lift those communities out of poverty through reforestation. Carbon reduction is a potential co-benefit, but it is not the mission.
While it’s clear that planting trees does offset carbon dioxide emissions, the potential impact has as much to do with quality as quantity. With a problem as complex as climate change, we need robust solutions—verified or not. No matter which type of tree planting project fits an organization’s needs and interests, it’s important to investigate how it goes beyond “just planting trees” and demonstrates meaningful ecological, economic, and social impact.
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