President Bush declared a state of emergency in northern California on Saturday as firefighters scrambled to control about 1,400 raging wildfires. Lightning is blamed for setting off the fires, including a massive blaze that has destroyed around 42 square miles (110 square kilometers) of forestland, along with 16 homes, and has threatened the Tassajara Zen Mountain Center, America's oldest Buddhist monastery in the Big Sur region of California.

U.S. Forest Service officials told the Associated Press that they are concerned there may be more wildfires than usual this summer, given the lower-than-average rainfall and activity so early in a season that typically peaks in late July and August.

The number of wildfires in the U.S. has increased in recent years, up from 7.2 million acres (2.9 million hectares) in 2002 to 9.3 million acres (3.8 million hectares) in 2007.

Check out Scientific American's wildfire coverage, including why global warming is expected to unleash more destructive fires. Also, see how scientists are learning to predict where, when and even how the next blazes will erupt.