Around the holiday season, thoughts turn to where to obtain the Christmas tree. Christmas trees are often a form of pine tree. Growing or freshly cut pine trees offer little danger of igniting. Pine trees can become highly flammable when allowed to dry out. Dryness occurs as the tree dies from lack of moisture over time. Living trees provide much greater resistance to combustion.
Several factors can increase the flammability in pine trees. A Firewise of Maryland study shows that these factors can include resin found in pine trees, needle shedding, low-hanging branches, dense foliage, and the ability to keep dried needles on the tree. The resin and dryness of dead needles can create a ready fuel source for fires.
The National Fire Protection Association states that nearly 250 fires are ignited each year from pine trees used as Christmas decoration, with more than 90 percent of these being indoor fires. Statistics show Christmas pine tree fires cause an average of 26 injuries and 14 deaths per year. The numbers have been decreasing and are nearly half the amount that occurred during the 1960s.
The Canadian Department of Forestry concluded in studies that cut pine trees allowed to stand in water or receive adequate water could not be ignited by match. It was also determined that if the moisture content dropped 50 to 85 percent the same tree would become ignitable and extremely flammable. The Forest Products Laboratory found that adding fire retardant chemicals to standing water would not reduce flammability when compared to plain water.
Pine trees exposed to dry heat or heat lamps can provide enough fuel to cause room fires; naturally dried trees burn sporadically and need a secondary fuel source such as paper to cause room fires. Artificially dried trees create up to 20 times the heat of naturally dried trees and can burn up to 10 times faster.
Pine tree fires can be reduced indoors by proper placement and maintenance. The NFPA recommends keeping trees a distance of 3 feet from heat sources, cutting fresh trees an additional 2 inches from the initial cut before placing it into a stand, and providing moisture daily to live trees.