Why Don’t We Just Plant More Trees?

Why Don’t We Just Plant More Trees?

Illustration Credit: Mattea Shuen

The challenges of tree-planting initiatives in addressing carbon emissions

Elizabeth Xu, Staff Writer 

Scientists from the European Union’s Copernicus Climate Change Service have recently confirmed that 2023 was the hottest year on record, with temperatures surpassing the 20th-century average by 1.4 degrees Celsius. This temperature rise dangerously approaches the 1.5 degree threshold set in the Paris Climate Agreement, beyond which there will be heightened challenges for human adaptation and ecosystem resilience. As per the Global Carbon Project, estimates anticipated that the 2023 carbon dioxide emissions would hit a record high of 40.9 gigatons, a significant increase from the predicted 36.8 gigatons released into the atmosphere in 2022. 

Each year, approximately 40 gigatons (40 billion tons) of carbon dioxide are emitted as a byproduct of human activities such as transportation, industry, and deforestation, contributing to 12–20% of global emissions. While progress has been made in reducing our carbon footprint through preventive measures and technological advancements, we continue to emit more carbon than nature can absorb. Numerous studies indicate that to achieve our goal of net-zero emissions by 2050, we need to achieve negative carbon emissions by removing carbon from the atmosphere. Research is underway to develop carbon capture technologies and promote tree planting as a means of achieving negative emissions. Planting trees not only helps restore the estimated 10–15 billion trees lost to deforestation each year, which accounts for 10% of global warming, but also enables the capture and storage of carbon in their leaves, stems, roots, and soil. However, it is important to note that a mature tree can only absorb 50 pounds of carbon dioxide per year and 1 ton of carbon dioxide over its lifetime, which means that a substantial number of trees would be needed. Some propose planting 40 billion trees annually to offset our yearly emissions, while others go to the extreme with the Trillion Trees Act. 

The Trillion Trees Act is a bipartisan bill adopted by the US government with the aim of sequestering 205 gigatons of carbon. It encompasses not only tree planting but also policies for conserving and restoring forests, conducting research, and implementing reforestation initiatives on public lands affected by wildfires, insect infestations, and disease outbreaks. If successful, this bill could offset two-thirds of our annual carbon emissions and compensate for 20 years of human-generated emissions, aligning with the goals of the Paris Agreement. The pursuit of extensive tree planting to fulfill the Paris Agreement has also inspired organizations to launch the Trillion Tree Campaign. This collaborative effort involving BirdLife International (BLI), Wildlife Conservation Society (WCS), and World Wide Fund for Nature (WWF) focuses on reducing deforestation, enhancing forest protection, and promoting restoration. Over the years, they have achieved success in reducing deforestation through legislative measures targeting the illegal timber market and have collaborated with local organizations engaged in reforestation efforts. 

Large-scale initiatives for reforestation have garnered support due to their merits. China, for example, has managed to offset 20% of its annual fossil fuel emissions since 2012 by implementing land use policies that have increased forest cover in southern China by 10 to 20%. These areas have been transformed into managed forests that act as carbon sinks. Some officials suggest that the reforested land in China could potentially offset up to 33% of the country’s annual fossil fuel emissions. The success story in China has fostered optimism regarding the impact of global reforestation efforts like the Trillion Tree Act and the Trillion Tree Campaign on the environment. 

However, despite the ambition of these large-scale tree restoration programs, there remains skepticism regarding the ability to meet goals. One key concern revolves around the timing of tree planting as a carbon capture strategy. Trees can take up to a century to reach maturity and absorb carbon at levels that significantly impact our carbon footprint. Furthermore, forests become carbon neutral once they reach maturity, as they reach an equilibrium where carbon uptake balances out with carbon released through the decay of organic matter. Scientists caution that there are limits to how much carbon forests can store and that tree planting alone will not be sufficient to counterbalance our carbon emissions. While planting trees is undeniably an effective method of increasing carbon uptake, efforts should also be directed at halting further deforestation. Between 1970 and 2010, the Amazon alone lost 100 million trees, representing a 20% deforestation rate. It takes decades for reforested trees to capture the same amount of carbon as previously existing ones, indicating that protecting older trees is more effective than relying solely on reforestation. Conservation efforts should also extend beyond forests to encompass grasslands and wetlands, which also possess significant carbon storage capacities. 

Nevertheless, it is crucial to support both local and international organizations involved in reforestation, as well as legislation to protect forests and reduce deforestation. While tree planting alone cannot solve our carbon emission problem, it has the potential to restore habitats and capture carbon as trees mature.