The Science of Fire: controlled burns

COVENTRY, R.I. (WLNE) — April’s wildfires in Exeter burned nearly 600 acres of the Queen River Nature Preserve.

While it may sound counterproductive, planned burning of forestlands helps make wildfires easier to tame.

When you think of forests, Southern New England may not come to mind. For folks like Patrick MacMeekin, the wildfire supervisor for the Rhode Island Department of Environmental Management, it’s a pretty big deal.

“New England and Rhode Island is a giant forest,” Rhode Island Department of Environmental Management Wildfire Supervisor Patrick MacMeekin said. “Over 50 percent of the state is forest land.”

On Nicholas Farm in Coventry RIDEM maintains the forest by using prescribed burns.

There are several reasons to send fire through an area in a controlled manner, chief among them is to remove the bulk of ground thatch and mid-level dead timber that would allow fire to spread fast along the ground and ladder up into the treetops.

That’s what happened in April in Exeter when an abandoned campfire was able to get up into the canopy, where it is near impossible to control.

“The primary objective of a lot of these burns is to promote wildlife habitat,” MacMeekin said.

In Coventry there is a concentration of critically endangered pitch pine trees, which compete for resources with the invasive white pine, which grows faster and taller.

The pitch pine ecosystem is critical habitat for animals like rare moths, butterflies and rabbits.

The pitch pine barrens actually depend on the occasional fire to come through in order to sustain the forest type. Prescribed burnings here also help with invasive southern pine beetles as well as the white pine problem.

“Pitch Pines, because they have really thick bark and a thick cambium layer, they’re resistant to fire,” MacMeekin said. “White pine has a very thin bark and a thin cambium layer so as fire comes through, it kills the white pines, but the pitch pines remain unaffected.”

The weather plays a big part for prescribed burns, as ideal conditions include humidity of 20 to 30 percent, light winds below 20 miles per hour to keep the burn from wandering out of the area, and the moisture content of the material to be burned should not be bone dry to keep control of the burn rate.

“By burning during periods of favorable weather conditions, we can burn in a controlled manner and remove the fuel components so that during periods of really high fire danger, if there was a fire coming through an area, that would be low intensity,” MacMeekin said.

RIDEM does controlled burns on state lands in three areas: Coventry, Exeter, and Prudence Island.