Since 1978, China has planted 66 billion trees as part of the Three-North program, a large-scale environmental initiative aimed at creating a green barrier to slow the spread of the Gobi Desert. This program covers regions that make up 45% of China’s territory and contain 84% of its desertified lands. Chinese officials plan to plant an additional 34 billion trees over the next 25 years, with the goal of reaching a total of 100 billion trees. However, the program has raised concerns about ecological consequences, such as a significant drop in groundwater levels in areas like Minqin, where levels have fallen by six meters. The program initially focused on planting monocultures—single-species forests—of fast-growing poplar trees. These were chosen for their ability to quickly establish structure in the landscape and grow rapidly. However, the poplars have been found to consume large amounts of water, worsening the strain on already limited groundwater resources. In 2000, a billion poplar trees in Ningxia were destroyed by a single plant disease, underscoring the risks of relying on a single species. A Chinese expert on desertification warned in 2017 that planting trees in arid regions could cause a rapid decline in soil moisture and groundwater levels. In response to these ecological challenges, the Three-North program has shifted its strategy since 2012, with support from an $80 million donation from the World Bank. The new approach emphasizes planting native species and drought-resistant shrubs instead of large monocultures of poplars and pines. This change reflects a growing understanding that planting trees in arid environments can lead to water shortages and disrupt local ecosystems. Researchers continue to caution that trees planted in such conditions may require more water than the soil can provide, which can have serious consequences for groundwater levels and local biodiversity. Efforts to address these issues have led to a more sustainable approach, focusing on species that are better adapted to the local climate. This shift highlights the importance of ecological balance in large-scale reforestation projects. While the Three-North program remains one of the largest afforestation initiatives in the world, its evolving strategies show a commitment to learning from past challenges and adapting to ensure long-term environmental benefits.