The Orange County Register reports that family members spotted the man's cellphone on the grass beneath the tree about 8:40 a.m. Sunday after spending hours looking for him.
Orange County Fire Authority spokesman Capt. Steve Concialdi told the newspaper that his body was seen at the top of the tree, resting against a power line.
About 20 homes in the area lost power while crews demagnetized the lines to allow firefighters to safely remove the man's body.
Investigators say the man posted a photo of the sunset to his Facebook page about 6 p.m. Saturday.