LOS ANGELES (AP) - An elderly motorist was killed Wednesday when a large pine tree fell on top of his car on a San Fernando Valley street, the Fire Department said. The accident occurred as the man drove south on Reseda Boulevard in Tarzana. The tree trunk crushed the roof of the victim's SUV. What caused the tree to fall was unknown. Witness Mel Harrison told KABC-TV he heard a crack and saw the tree coming down.