LAST WEEK’S “BURN WEEK” was the largest prescribed burn in the Wildflower Center’s history: 61 acres ablaze in two days. A crew of 20 worked on the fires, including center staff, several crews from the Austin Fire Department, Austin Water Utility and The Nature Conservancy. Why would a place that promotes native landscapes burn them? Prescribed fire mimics what would have been naturally occurring wildfires in our native ecosystems. It offers an alternative to mowing and herbicides, and best of all, native plants usually survive because they evolved with wildfires. In fact, wildflowers tend to thrive after fire.
“The prairie landscapes of Texas historically were hit with wildfires every 3 to 12 years, so there are whole communities of native plants need fires to be healthy,” said Land Steward Michelle Bertelsen. She has participated in about 15 prescribed burns since the Center’s Hill Country Research Program began in 2001. Like the nine other participating staff, Bertelsen has current training on wildland and prescribed fire operations through the National Wildfire Coordinating Group, and is among those with added Texas Prescribed Burn School training.
Depending on the season, staff and their collaborators use fire to help increase the grasses available for grazing animals, to reduce the presence of aggressive, non-native plants, to reduce the risk of wildfires and for other benefits. A center study has shown, for instance, that prescribed fires in the summer help keep invasive King Ranch bluestem in check.
The center’s Savanna Meadow, just north of the Visitors Gallery, was burned Sept. 30 to improve the diversity of wildflowers and other plants there next spring.
“Fire helps remove the thatch layer on the soil surface, creating a more open canopy that helps forbs and other native plants germinate,” said Matthew O’Toole, a center environmental designer who has been the burn boss on site in recent years.
The crew also targeted a small plot within the Texas Arboretum and a plot of 35 acres deep within the center’s campus. The plot is among those on the 279 acres left untouched to foster survival of native plants and wildlife.
Without fires, the plot had become thick with Ashe juniper, cedar elms and other vegetation. The center seeks to return sites like this on campus to their historical savanna condition: a grassland dotted with a few trees that is favored by scissor-tailed flycatchers, bobwhite quail, armadillos and other wildlife.
“We’re trying to shift the plant community that we have here from Ashe Juniper woodland back to a savanna condition that once occurred throughout Central Texas,” O’Toole said.
Dead tree limbs and other vegetated materials had also accumulated on the 35 acres, adding to the fuel load – and potential danger – of any wildfires there.
“It sounds counter-intuitive, but one of the best tools for preventing out-of-control wildfires is prescribed fire,” O’Toole said. “We need these burns in our toolbox to proactively manage the Wildflower Center campus.”
The research Wildflower Center landscape restoration staff has conducted with prescribed burns has revealed that:
- Summer prescribed burns can reduce the invasive, non-native grass, King Ranch bluestem and increase the diversity of spring wildflowers such as black-eyed Susan and Indian paintbrush.
- Winter burns can result in more native prairie grasses such as little bluestem and curly mesquite.
- Fall burns can result in more diverse wildflowers overall.