On November 28, 2024, a crew on the southern rim of the Taklamakan Desert planted the final 100 meters of a line of trees that had been 46 years in the making. With that stretch, according to Chinese state media, the country closed a 3,046-kilometer green belt encircling its largest desert, a continuous ring of vegetation around a sea of sand roughly the size of Finland. It was a landmark moment for the largest tree-planting effort in human history. It was also, measured against the plan behind it, only about two-thirds of the way done.
China’s Massive Tree Planting Strategy
The belt around the Taklamakan is one piece of the Three-North Shelterbelt Program, the afforestation campaign the world knows as the Great Green Wall.
Launched in 1978 to slow the advance of the Gobi and Taklamakan deserts across northern China, the program has so far put an estimated 66 billion trees into the ground, and Chinese authorities plan to plant roughly 34 billion more over the next 25 years, which would carry the eventual total to around 100 billion. The wall is scheduled to keep growing until about 2050, when it is meant to form a barrier stretching close to 4,800 kilometers across the country’s north. Nearly half a century in, the most ambitious ecological engineering project on Earth is far from finished.
The idea was not entirely without precedent. In the 1930s, in response to the Dust Bowl, the United States planted some 220 million trees in a shelterbelt running from the Canadian border toward Texas. China’s effort dwarfs that undertaking many times over, and its purpose is just as concrete. Desertification has long threatened farms, cities, and settlements across northern China, and the sandstorms that rise off the dry ground each spring blow away topsoil, bury newly exposed land, and carry choking dust as far as Beijing. The wall was built to blunt exactly that, slowing dune movement and breaking the wind.
The scale already achieved is hard to overstate. China’s national forest coverage has climbed from about 10 percent of its territory in 1949 to more than 25 percent today, even as its population nearly tripled, and the program has reforested tens of millions of hectares of arid and semi-arid land. The original goal, set in 1978, was to raise forest cover across the three northern regions from roughly 5 percent to 15 percent, a target the program is still working toward as it enters its final and longest phase, running from 2021 to 2050.
The Great Green Wall’s Big Ambitions
For decades, skeptics questioned whether planting trees on this scale did much beyond producing impressive numbers. New research has complicated that skepticism in China’s favor. A study published this year in the journal Geophysical Research Letters found that, measured by satellite, the planted sections of the forest are increasing their leaf cover faster than China’s naturally occurring woodland. The topline figure was striking, a 66 percent faster growth rate, though the researchers were careful to explain most of that gap. Planted stands in China are on average much younger than natural ones, and young trees add leaf area faster simply by being earlier in their growth curve. When the team controlled for age and growing conditions, the advantage shrank to a more modest 4.6 percent, still faster, but far smaller than the headline suggested.
The reason planted forests pull ahead at all appears to be a mix of species and management. Much of the wall favors fast-growing trees such as poplar and eucalyptus, often actively tended, with competing vegetation cleared away, and that reduced competition lets the trees take fuller advantage of rising atmospheric carbon dioxide, a growth-boosting effect sometimes called CO2 fertilization. The edge does not last forever. The growth-rate gap peaks when planted trees are around 30 to 40 years old and then fades, while natural forests keep growing on a longer trajectory. As study lead author Yuhang Luo of Peking University put it, for long-term carbon storage and resilience, natural forests remain irreplaceable.
An even more striking finding has emerged from the desert itself. Using NASA satellite instruments to track carbon dioxide and vegetation, a separate team reported in the journal PNAS that the greening ring around the Taklamakan is now absorbing more carbon dioxide than the desert releases, tipping a landscape once described as a biological void into a net carbon sink. For a barrier built simply to hold back sand, becoming a measurable drain on atmospheric carbon is an unplanned bonus with global, not just local, significance.
None of this means the Great Green Wall has been an unqualified success, and the honest accounting includes real failures. Tree survival has been a persistent problem: one analysis of the program’s first four decades found that only about one in five of the plots that survived initial planting had become proper forest within ten years, and only about one in ten remained alive after 40. In 2000, a single disease outbreak killed roughly one billion poplars in Ningxia, wiping out about two decades of work in one province and illustrating exactly the danger critics warn about with fast-growing monocultures, which support little biodiversity and are vulnerable to pests. Others, including biologists who study the project, note that dense planting in dry regions can draw down groundwater the surrounding land cannot spare, and satellite research covering 2001 to 2020 found that some regions grew visibly greener even as water stress deepened, more leaves pulling more moisture from the soil each day.
The deserts, for their part, have not surrendered. China’s desertified land has edged down only slightly over the past decade, from 27.2 percent of the country to 26.8 percent, and the Gobi still swallows well over a thousand square kilometers of grassland a year. Reforestation and desertification are moving in the right directions at once, slowly, rather than one decisively defeating the other. That is the real state of the world’s largest forest: a 66-billion-tree wall that has measurably greened a nation and surprised its own critics, still only two-thirds built, with a quarter-century and tens of billions of trees to go before anyone can say how the story ends.
About the Author: Harry J. Kazianis
Harry J. Kazianis (@Grecianformula) was the former Senior Director of National Security Affairs at the Center for the National Interest (CFTNI), a foreign policy think tank founded by Richard Nixon based in Washington, DC. Harry has over a decade of experience in think tanks and national security publishing. His ideas have been published in the NY Times, The Washington Post, The Wall Street Journal, CNN, and many other outlets. He has held positions at CSIS, the Heritage Foundation, the University of Nottingham, and several other institutions related to national security research and studies. He is the former Executive Editor of the National Interest and the Diplomat. He holds a Master’s degree focusing on international affairs from Harvard University.
