In efforts to stop repeats of this summer’s deadly and devastating wildfires that have scorched millions of acres in California, Washington State and Alaska, European researchers are taking a very close look at the cypress, a tree known to have fire retardant qualities
Researchers in Spain and Italy have found cypress trees ignite seven times slower than other species.
The lead author on a study the researchers published in the Journal of Environmental Management, Gianni Della Rocca said “The peculiar flammability traits of cypress are not a real mystery. The physical, chemical and biological characteristic of this species makes it not immediately prone to fire. It means that cypress burns, but it takes longer to catch fire than other Mediterranean species.”
Della Rocca said the researchers carried out tests on the “Cupressus sempervirens” species, a Mediterranean native. “A wide set of bench-scale calorimetry techniques were used to test the flammability parameters of live crowns and litter samples.” in the lab. He said they also planted live green barriers in the wild which, when they mature, will be tested to see how effective the barrier's fire resistance is and if they can achieve the same results as the lab tests in actual wind conditions.
Della Rocca said the lab tests showed cypress trees would help fight wildfires of "moderate intensity" as needles and dead litter that fell from the trees are spongy, holding water for long periods, and that the " widely-spaced structure of the tree’s crown slows down air circulation, and the space between branches reduces the speed at which a fire spreads." The study also found cypress sap was less flammable than other tree resin
The research project was inspired by data which showed in a 2012 wildfire in Valencia, Spain, which destroyed 50,000 acres, only two percent of the area's cypress trees burned.
Della Rocca said the trees which grow in a wide variety of soil and climate conditions could be used used as buffer zones in California and other dry and high temperature areas.
Although environmentalists say the introduction of non-native plants increase the risk of damaging the native ecosystem, Della Rocca said the researchers are doing additional tests to see how the the trees' effects, if at all, non-native areas.
He said he wants to make it clear the researchers were not advocating for "neat hedges of cypress trees" because for them to be effective they have to grow randomly as they did in the wild.
“When we consider the cypress trees as a potential barrier able to reduce or slow down the fire initiation risk, we’re referring to multiple-row plantations with homogenous structure made by selected healthy and vigorous plants,” said Della Rocca.