The world's largest forest restoration experiment
- Editorial Team SDG15
- Jul 24
- 8 min read
Published on 24 July 2026 at 05:52 GMT
By Editorial Team SDG15
For decades, discussions about environmental issues have often focused on emissions, rapid industrialisation and pollution in major cities. Yet another environmental initiative has attracted increasing international attention for a very different reason. Since 1978, China has been developing the Three-North Shelter Forest Program, popularly known as the Great Green Wall.
It is a long-term ecological restoration initiative designed to run until 2050. Its area of intervention extends across north-east, northern and north-western China, together covering around 42 per cent of the country's territory. This does not mean the entire area will become forest. The programme combines shelterbelts, grassland restoration, dune stabilisation and other landscape restoration measures intended to protect soils, farmland and communities. A scientific review published in Science of the Total Environment, based on more than one hundred peer-reviewed studies, describes it as the largest afforestation programme ever undertaken.
Its principal objective is to reduce the impacts of desertification, wind erosion and sandstorms while protecting agricultural land and improving environmental conditions across northern China. Rather than creating a continuous wall of trees, the programme seeks to establish a vast network of vegetation capable of reducing wind speeds, stabilising soils and limiting the movement of sand.
The initiative responds to environmental, social and economic challenges. Northern China contains extensive arid and semi-arid regions affected by water scarcity, strong winds, climatic variability and decades of land degradation associated, depending on location, with intensive farming, overgrazing and historical vegetation loss. Soil erosion and sandstorms damage ecosystems, threaten food production, disrupt infrastructure and affect the health and livelihoods of millions of people.
A transformation on an extraordinary scale
Reuters reported in November 2024 that more than 30 million hectares of trees had been planted since the programme began, covering roughly 300,000 square kilometres. The news agency also reported the completion of a 3,000-kilometre green belt surrounding the Taklamakan Desert in Xinjiang after 46 years of restoration work.
China's overall forest expansion has also been remarkable, although it should not be attributed solely to this programme. Reuters reported that official figures showed national forest cover had exceeded 25 per cent by the end of 2023, compared with approximately 10 per cent in 1949. In Xinjiang, one of China's driest regions, official statistics cited by Reuters indicate that forest cover increased from around 1 per cent to 5 per cent during the past four decades.
These figures reflect the combined impact of several national forestry and ecological restoration programmes rather than the Three-North Shelter Forest Program alone. Nevertheless, the programme remains one of the central pillars of China's long-term environmental strategy.
Carbon storage
One of the principal environmental benefits of forest expansion is its capacity to remove carbon dioxide from the atmosphere and store carbon in trunks, branches, roots and soils. Here again, however, it is important to distinguish between China's overall achievements and those directly attributable to the northern restoration programme.
A 2024 study published in Nature Communications, combining satellite observations with field measurements, found that China's planted forests expanded by 94.33 per cent between 1990 and 2020, increasing from approximately 46.5 million hectares to 90.3 million hectares.
During the same period, carbon stored in the biomass of these planted forests increased from approximately 675.6 million tonnes of carbon to 1.87 billion tonnes, representing an additional 1.2 billion tonnes of stored carbon over three decades, or an average annual increase of around 40 million tonnes. According to the researchers, roughly 53 per cent of this increase resulted from expanding forest area, while the remainder reflected the continued growth of existing forests.
These figures refer to China's planted forests as a whole rather than specifically to the Three-North Shelter Forest Program. The same study also found that carbon accumulation was considerably slower across northern and north-western China because arid conditions limit tree growth. Estimated annual increases were around 3.5 million tonnes of carbon in northern China and 3.1 million tonnes in the north-west, substantially lower than in the wetter eastern and southern regions.
This illustrates an important ecological principle: planting trees in dry environments does not necessarily produce the same climate benefits as planting them where rainfall and growing conditions are more favourable.
A second study published in Nature Communications examined China's future restoration potential. Under a scenario compatible with current ecological management policies, planting an additional 44.7 billion trees could eventually store around 5.9 billion tonnes of additional carbon. However, this represents a modelled long-term potential rather than carbon that has already been captured. The authors also concluded that increasing tree density within existing forests could, in many locations, be more effective and cost-efficient than establishing entirely new plantations in environmentally unsuitable areas.
What appears to have worked
The available scientific evidence indicates that the programme has produced measurable environmental benefits, although these vary considerably between regions. The review published in Science of the Total Environment concluded that, during its first four decades, the programme contributed to reducing wind and sand hazards, limiting soil erosion, increasing forest carbon sequestration and, in certain areas, improving agricultural productivity and local economic activity.
Shelterbelts reduce wind speeds and help protect crops from soil loss and physical damage. Vegetation also stabilises dunes, traps sediment and gradually improves soil quality through the accumulation of organic matter. Where suitable species have been selected and local water availability respected, these measures have strengthened landscape resilience.
The programme has also generated valuable scientific knowledge. Over several decades, researchers have tested different tree species, planting densities and restoration techniques. Reuters noted that the green belt surrounding the Taklamakan Desert resulted from years of experimentation aimed at identifying vegetation capable of surviving some of the harshest environmental conditions on Earth.
Perhaps this accumulated experience represents one of the programme's greatest achievements. Rather than persisting with a single strategy, restoration practices have gradually evolved to include dune stabilisation, native vegetation recovery, grassland restoration and planting schemes better adapted to local ecosystems.
What has not worked as expected
The same body of evidence also points to important shortcomings. One of the principal weaknesses during the early stages was the assumption that planting large numbers of trees would automatically restore ecosystems.
Experience has shown that restoration success depends heavily on matching species to local environmental conditions. In some arid and semi-arid regions, early planting efforts experienced high mortality because species were introduced into environments with very limited water availability or conditions poorly suited to long-term survival. Subsequent research has demonstrated that restoration outcomes improve significantly when species selection, planting density and management practices are adapted to local ecological conditions.
Water availability has proved to be one of the principal limiting factors. In areas with very low rainfall, trees may compete with native vegetation, agriculture and local communities for scarce water resources. Yao and colleagues warn that forest expansion in parts of northern China could create trade-offs with other ecosystem functions and place additional pressure on already limited water supplies. The authors also emphasise that further research is required before the full extent of these interactions can be understood.
Not all forests provide the same ecological value. Monoculture plantations, where large areas are planted with a single species, are generally more vulnerable to pests, diseases, drought and wildfire than more diverse ecosystems. Likewise, an increase in tree cover does not necessarily translate into a proportional recovery of biodiversity. Ecological restoration therefore requires consideration not only of the number of trees planted but also of species diversity, ecosystem function and long-term resilience.
The programme's impact on sandstorms also remains the subject of scientific discussion. Reuters has reported criticism suggesting that low survival in some early planting efforts and the continued occurrence of sandstorms indicate limited success. Conversely, academic reviews have identified measurable reductions in wind erosion and sand-related hazards across several regions. The most robust scientific conclusion is therefore neither that the programme has eliminated sandstorms nor that it has failed. Outcomes differ considerably according to geography, climate, vegetation type and local management practices.
Desertification itself has not disappeared. According to official figures cited by Reuters, 26.8 per cent of China's land area was still classified as desertified in 2024, compared with approximately 27.2 per cent a decade earlier. Although the reduction is modest, it suggests that the long-term expansion of desertified land has at least been slowed or stabilised in recent years.
More than a tree-planting campaign
Perhaps the programme's most important scientific lesson is that ecological restoration cannot be measured simply by counting trees. Success depends on long-term survival, water availability, soil recovery, biodiversity and the ability of restored ecosystems to function without continuous human intervention.
In some landscapes, planting trees may be the most appropriate solution. In others, restoring native grasslands or shrublands, protecting existing vegetation or encouraging natural regeneration may deliver better ecological outcomes. Arid ecosystems should not automatically be considered degraded simply because they do not resemble forests.
This broader ecological understanding increasingly appears to shape the programme's more recent phases. Greater emphasis is now placed on native species, water efficiency and restoration strategies that combine trees, shrubs and grasslands according to local environmental conditions. Rather than pursuing a continuous forest barrier, the programme has gradually evolved towards a mosaic of restoration approaches adapted to different landscapes.
An effort worthy of recognition
The Great Green Wall is neither a perfect solution nor proof that desertification has been defeated. Equally, it would be misleading to attribute every increase in China's forest cover or carbon storage to this single programme.
Yet focusing only on its shortcomings would also present an incomplete picture. Sustaining an ecological restoration initiative of this scale for almost half a century represents an environmental commitment rarely seen elsewhere. The programme has protected vulnerable land, generated valuable scientific knowledge, corrected earlier mistakes and demonstrated that ecological restoration requires sustained investment over decades rather than short political cycles.
At a time when many environmental policies are assessed over only a few years, planning restoration over more than seven decades is remarkable in itself. Ultimately, the programme's long-term success will depend less on the number of trees planted than on the resilience, biodiversity and ecological functioning of the landscapes it seeks to restore.
Perhaps its most valuable lesson is that large-scale restoration is an adaptive process. Scientific monitoring, continuous learning and the willingness to modify strategies in response to new evidence appear to be as important as the original planting effort itself. In that respect, the Three-North Shelter Forest Program demonstrates that restoring degraded landscapes is a slow, complex and imperfect undertaking, but one capable of delivering significant environmental benefits over time when supported by long-term commitment and evidence-based management.
Further information
Nature Communications — Cheng, K. et al. (2024). Carbon storage through China's planted forest expansion. Nature Communications 15, 4106.
Nature Communications — Yao, L. et al. (2024). Carbon sequestration potential of tree planting in China. Nature Communications 15, 8398.
Science of the Total Environment — Zhai, J. et al. (2023). Assessing the effects of China's Three-North Shelter Forest Program over 40 years. Science of the Total Environment 857, 159354.
Reuters — Coverage of the Three-North Shelter Forest Program, including the completion of the Taklamakan Desert green belt, official forestry statistics and recent progress in desertification control. 29 November 2024.
