The seemingly-healthy tree that crashed down near Victory Square and caused traffic disruptions Tuesday afternoon was rotting from the inside, according to officials.

Park staff said an internal decay called internal white crown rot caused the 70-year-old tree to knock down live trolley wires and fall on top of two cars in downtown Vancouver during rush hour.

“You could hear a loud cracking noise,” said witness Ben Simmons. “We heard the noise and just saw this giant tree fall out onto the road. And just a lot of commotion, cracking and banging, knocking poles over."

Vancouver Film School student Alyssa Mack-Lee said she never expected a tree to fall in the heart of a metropolis.

"It's definitely abnormal,” she said. “I'm from a small town so we see trees fall all the time, but in a city? That's pretty crazy."

Several people were trapped in their cars and buses were re-routed for about one hour until TransLink arrived and turned off power to the wires.

The tree was cleared from Cambie Street and city arborists are expected to assess other nearby trees for similar decay.