Firefighters from the Newport Beach Fire and Marine Department will participate in a safety demonstration today in Santa Ana. The firefighters will join other public safety agencies in providing safety tips during the holiday season for those who will have a Christmas tree at home. A Christmas tree will be set on fire at 10 a.m. in Centennial Park as part of the demonstration. Firefighters will show various ways to extinguish a tree that catches fire. Fire agencies say they respond to numerous problems during the holiday season that result from improper care of trees. The trees can be a major fire hazard, generating more than 2,000 degrees of radiant heat when consumed by fire, officials said.