What or who started the california wildfire????

Answer 1

The major contributing factors to the extreme fire conditions are the drought in Southern California, the hot weather, and the unusually strong Santa Ana winds with gusts reaching 85 mph (140 km/h).

Some of the fires were man-made:

Several of the fires were triggered by fallen power lines.
At least one fire is known to be the result of arson;
One fire was started by an overturned semi-truck.
Another was reported as having been deliberately caused, a suspect being shot and killed at the scene by state authorities.
The causes of the remaining fires remain under investigation. Authorities predicted wind conditions would not improve until October 25, 2007.[14] Those predictions proved to be correct as wind speeds slowed to the single digits, allowing firefighters to make progress more quickly.