As 323 active fires in California threaten more than 10,000 homes, commercial buildings and other structures, the Sacramento Bee today offered a small consolation. Even though air quality is poor and the state has already spent more than $100 million fighting blazes, the situation isn't really anything abnormal.

The Bee story, citing research by UC Berkeley environmental scientists that was led by Scott Stephens, said the amount of land burning pales compared to acreage consumed historically, before Europeans settled in California.

"The scientists estimated that an average 4.4 million acres burned annually in California before 1800, compared with an average 250,000 acres a year in the last five decades," the story says.

The smoke-filled skies are, in historical terms, unexceptional. The Berkeley researchers found that wildfires emitted on average 1.3 million tons of smoke particles a year in prehistoric California, compared with about 78,000 tons in 2006, the most recent year for which the data is available.