WORCESTER, Mass. — It only takes a minute for a crispy Christmas tree to touch off a raging inferno.

Researchers who set up a mock living room complete with curtains and armchair — and then hit “record” as a tree-turned-torch engulfed the room in 63 seconds — hope the video will help people stay safe this season.

“This has only been one minute since time of ignition and we’re seeing that the carpet has now ignited and that’s an indication of what we call flashover, where the room has gone from local burning at the tree to complete room involvement,” said Raymond Ranellone, director of the Fire Protection Engineering laboratory at Worcester Polytechnic Institute.

“So in your home, that’d be your entire living room on fire in just over one minute,” he said.

Engineers at the Massachusetts university staged the live exercise Tuesday as city firefighters stood by. They used a harvested tree that was left unwatered for three weeks, recreating conditions that often occur after people decorate their homes for the holidays.

First, they touched the tree with a blowtorch. Instantly, the lower branches ignited. A few seconds later, flames were shooting out of the arms of the chair and thick smoke was billowing. Then the fake room was engulfed in a real fireball.

“This truly was alarming, truly surprising for us to see us going from an ignition all the way to a flashover in this compartment in just 63 seconds,” said Ranellone. “And when we start to think about what 63 seconds means — that’s how much time we need to get out of the house, to alert the fire department and get the fire department to our houses. Sixty-three seconds is just not a lot of time.”

Christmas trees were to blame for an average of 210 house fires annually between 2009 and 2013, according to the latest available data from the National Fire Protection Association. Those fires killed seven people, injured 19 others and caused $17.5 million in property damage, the organization said.

“The best way to prevent a Christmas tree fire is to water it well every day, place it well away from heat sources, and dispose of it soon after the holiday,” said Massachusetts Fire Marshal Peter Ostroskey.

He said it’s always a good idea to turn off lights on the tree when leaving the house or going to bed.