China's Great Green Wall is Holding the Desert Back

China's arid north is slowly being invaded by its own desert, which is the source of growing dust storms and nearly useless land. To fight it, they are planting whole forests - a living wall of hearty trees to keep the desert at bay... and it's working.

That's at least according to a study recently published in the journal Land Use Policy, which details how China's "Great Green Wall" has helped shelter the country from dust storms while simultaneously helping to reintroduce vegetation into the fringes of what was thought to be a hopeless dust bowl.

Of course, the wall, officially called the Three-North Shelterbelt Forest Programme, is a project long in the making. It takes time to transplant and grow a forest, and the project had very small beginnings back in 1978. Now looking a lot more like the "living wall" that ecological engineers envisioned, the plan is due for completion in 2050, and will contain more than 100 billion trees covering more than a tenth of China.

So far, according to the study, things are looking good for the project. Measuring dust storm intensity (DSI) for regions bordering China's Gobi and Taklamakan deserts, researchers found  the growing forest was doing its intended job. Most notably, there was a significant drop in DSI between 1981 and 1998, leading to slightly improved air quality for regions as far as Beijing.

The researchers also noted that this was not just the consequence of natural effects unrelated to the wall. Their analysis showed that DSI and vegetation rose and fell with precipitation deeper into the dust bowl regions, but near the walls, improvements were constant and unwavering.

And that's great news for other ongoing projects, such as the Global Environment Facility Initiative that is placing a Great Green Wall in a 4,400-mile stretch across Sahelian Africa (between the Sahara Desert and the Sudanian Savanna).

Still, there is some criticism of these projects. A main concern is that planting forests where they don't naturally belong may ultimately backfire, turning these projects into massive wastes of time and money.

David Shankman, of the University of Alabama in Tuscaloosa, recently told New Scientist that he is concerned about the unknowns.

"What is the mortality rate of planted trees? What happens when they die? And how do these trees affect grass and shrubs, which in general are more resistant to drought and more effective at erosion control?"

These are the questions, he said, that should be answered before governments and international organizations endeavor to throw even more resources into Great Green Walls.

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