Monday of last week, Arboretum staff, student workers, and community volunteers kicked off the prescribed burn season in the Arb with a small fire in the 2003 prairie of the lower arboretum. Known as a burn break, it didn’t cover a full zone, or much acreage, but rather burned along a mowed path in the prairie to improve its ability to act as a firebreak in subsequent burns. Most importantly, the burn gave workers a chance to test and double check fire equipment. An important part of preparing for each fire season is testing each piece of equipment, and pickup on any equipment failures so they aren’t first discovered on the day of a big fire. Despite this burn’s small size, every piece of fire equipment was tested at the burn break - from the dump truck’s 400 gallon mountable tank, hosing, and pump, to the flappers and rakes and the backpack tanks carried by individuals.
Luckily, there were no equipment malfunctions, and more than 200 meters of mowed path was burned clear of vegetation and fuel. Many sections of prairie surrounded by hard breaks like gravel trail are too large to burn on their own. They must be subdivided by mowed breaks to create more appropriate management units and, because these mowed breaks leave thatch and other fuel on the ground where a fire is opposed to stop, it makes raking or burning away the vegetation along these borders essential for a safe and effective burn. The only question now is if this section and others will be able to burn before the season ends.
Because snow cover extended into May and the recent cold wet weather has prevented burning at the normal start of the season in mid-April, the fire season has already lost three weeks. If temperatures keep steadily rising to the point that burns can’t be effectively managed, some sections will even have to wait until next season to burn. Woody species and invasive plants sensitive to fire are always attempting to colonize the prairie with seed brought by birds, scat, or winds. Without fire this season, it’ll be that much more important in the fall that zones behind schedule are burned to balance species composition, consume thatch, and reinvigorate growth of native species by returning trapped nutrients to the soil.