A study from University of Nevada Cooperative Extension's Living With Fire Program shows that most common mulches are combustible under dry, hot and windy weather conditions but that different mulches vary considerably when it comes to flame height and the spread of fire.
UNCE Natural Resource Specialist Ed Smith, working with researchers from the University of California and other area agencies, found that shredded rubber, pine needles and shredded western red cedar demonstrated the "the most hazardous fire behavior," while composted wood chips produced only incidental flaming and smoldering.
Smith said the research is important for residents living in Nevada's high fire hazard areas. Mulches are valuable when it comes to conserving water and controlling weeds, Smith said, but certain types of mulch will endanger homes during a wildfire, when embers can travel great distances ahead of the main blaze.
"Unfortunately, some types of mulch can ignite during a wildfire and threaten homes," Smith said. "It is important for residents of wildfire prone areas to exercise care when using mulches near their houses."
A free publication detailing the results of the study, "The Combustibility of Landscape Mulches," is now available through Cooperative Extension's Living With Fire program. The new publication provides recommendations on how to safely use mulches in residential landscapes.
The study of eight different mulch types commonly used in Northern Nevada was conducted in the spring of 2008 in collaboration with the Carson City Fire Department, Nevada Tahoe Conservation District and the Natural Resource Conservation Service. Researchers established plots of eight different mulch treatments, and after exposing them to summer weather for 2 1/2 months, the plots were ignited and evaluated.
A free copy of "The Combustibility of Landscape Mulches," is available by calling University of Nevada Cooperative Extension at (775) 784-4848 or downloading it at LivingWithFire.info.