Researchers who set up a mock living room complete with curtains and an armchair — and then hit "record" as a tree-turned-torch engulfed the room in 63 seconds — hope their video will help people stay safe this holiday season. [...] they touched the tree with a blowtorch. "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. Since about one-third of tree fires are blamed on electrical problems, he said it's always a good idea to turn off lights on the tree when leaving the house or going to bed.