The man is believed to be a private tree trimmer. He was working at 6351 N. Hiawatha Ave. on the city's Far Northwest Side when the accident happened.
The man was working around 9 a.m.
Neighbors were out and about. One woman saw the whole incident, and she called for help. She says she thought the man was dead at first.
"I saw fire come out of his head and his feet. Then, he did begin to move, and he was able to climb down himself," said Jenny Koller.
It is not clear which tree trimming company the man works for.
He was taken to Advocate Lutheran General Hospital in Park Ridge.