Three Gorges Dam murky. In 1997, the Three Gorges area had 10% forestation, down from 20% in the 1950s. Research by the United Nations Food and Agriculture Organization research suggested that the Asia-Pacific region would, overall, gain about of forest by 2008. That is a significant change from the net loss of forest each year in the 1990s. This is largely due to China's large reforestation effort. This accelerated after the 1998 Yangtze River floods convinced the government that it must restore tree cover, especially in the Yangtze's basin upstream of the Three Gorges Dam. Concerns about the potential wildlife impact of the
Three Gorges the river along vertical fractures, forming precipitous cliffs. When the river flows through areas of softer sandstone and shale, which have less resistance to erosion, the erosive effect is increased, carving wide valleys. There are different theories on how the Three Gorges were formed, but geographers and geologists have generally reached a consensus, believing mountain folding in the east of Sichuan Province and the west of Hubei Province, including the Wu Mountains (), were the outcome of the Yanshanian movement () around 70 million years ago. The gorges run from southwest to northeast, then turn, and from west to east,