He went back up on the stick boom lift to troubleshoot the team's work when one of the workers reported hearing a crash from up the hill at around 6:20 p.m. Friday.
Lourie Morgan is a registered nurse who lives across Willamette on 49th Avenue. She was the first person at the scene and helped assist the man until firefighters arrived.
"I heard this loud crash... I came outside and he was laying face-down by that tree. He had blood coming out of his mouth," said Morgan.
She said the man had very belabored breath when he was taken to the hospital.
Police officials said the man was wearing a harness when the lift tipped over.
Willamette was closed down between 48th Ave. and Coachman Drive for a short time while crews worked the scene.