Scientist, UK
05-18-07
The Green Wall of China
With the Beijing Olympics just a year away, and desert dunes now only 150 miles
away from the city, officials have been dreaming big when it comes to battling
legendary Chinese sandstorms in the capital and across the country’s arid north.
In 2001, the government approved a new phase of an $8 billion
antidesertification campaign, stretching from the capital to Inner Mongolia. The
4,500 kilometer shelterbelt – with 25 million hectares of trees planted and 10
million more hectares planned by 2050 – has been the world’s largest
reforestation campaign.
Mega antidesertification campaigns have worked in the past. The Dust Bowl of
the American west in the 1930s prompted the creation of a 100 mile-wide
shelterbelt that stretched from Canada to Texas. “It was very successful and did
a lot for controlling erosion, providing wildlife habitat, and protecting farmsteads,”
says James Brandle, a professor at the University of Nebraska, Lincoln.
According to a spokesperson for China’s State Forestry Administration, the
project is on the right track: Between 1999 and 2004 (the last year data was
available), 8,000 square kilometers of desert were rolled back, and 300 million
tons of sand were prevented from flowing into the Yellow River. Around 2,500
square kilometers of land is lost each year to the expanding Gobi Desert. He also
says by 2010, 40% of land currently affected by desertification will be brought
under control, although he didn’t say whether that land would be arable.
Still, Eugene Takle, an agricultural meteorologist at Iowa State University,
says the Great Plains of the 1930s and the arid northeast of China in the new
millennium are not parallels. “The 1930s were just an extreme period that hasn’t
been revisited,” he says. “However, in China you’re trying to put trees in a place
that’s always been the desert, so you’re going uphill against nature in that one.”
Others are also skeptical. Among a list of failings, a recent United Nations report
criticized the “poor planting techniques and lack of maintenance” and “poor
matching of species and clones to site conditions.” For example, 1,200
kilometers of the Green Wall withered and died in Gansu Province when the
high-tech dune-fixing trees inadvertently sucked up too much water, says
Yuanchun Shi, soil conservationist and former president of China Agricultural
University. “Stressing the role of trees over grass and thickets was an arrogant
and ill-thought out plan that contradicted scientific and economic rules,” he adds.
Countless trees were recently planted in the capital, but moths appeared out of
nowhere to strip their foliage along with the hopes for a green Olympics.
And despite the trees, Beijing will continue to suffer from sandstorms, says Shi,
because airborne particles blow above the tree line. Nontheless, Shi is quick to
shrug off talk about Beijing’s plights, saying a disproportionate amount of funds
have gone to the capital while neglecting the rest of the region – 4 million square
kilometers (40% of the country’s landmass) that the Green Wall protects. Shi
says simpler measures would cost less money but be equally effective at
stopping desertification, such as controlling sheep-grazing patterns.
Xinhua Zhou, a shelterbelt ecologist at University of Nebraska, Lincoln, says
more hard science needs to be done. “We really need to analyze the historical
data on sandstorms, examine the structure of turbulence flow, and see what
vegetation can minimize these sandstorms.”
Bruce Wight, an agroforester at the US Department of Agriculture, says
shelterbelts are normally used to stop the encroachment of the desert. He
wonders about the 8,000 square kilometers of land reclaimed from
desertification: “I’d be skeptical how feasible that is.”