Prescribed Park Burn

by Jim Eagleman

A prescribed burn—a long-debated strategy for resource management at many Department of Natural Resources (DNR) state parks and reservoirs—took place in March of this year at the Brown County State Park. The term “prescribed” is used to reflect the concern for the forest health similar to a doctor’s concern for a patient’s welfare. A prescription is written and the treatment follows.

For the past 80 years, Brown County State Park has extinguished property fires as soon as they occur. Utilizing DNR fire crews and local volunteers, escaped flames from abandoned campfires or lightening strikes were quickly brought under control. This “suppression” allowed for public safety—everyone’s first concern. But the policy denied the natural benefits that could result from letting fire proceed. Natural area management has moved to reinstate fire on the landscape. Of course, human safety still remains a top priority.

Indiana has always had forest fires. Historically, lightning storms caused fire to burn throughout southern Indiana’s extensive woodland from the Ohio River to the Wabash. Native Americans used fire to clear land for living and garden space, to move game, and to encourage grasses and shrubs. The study of fire scars in old tree stumps (the science of dendro-chronology) confirms how often and how intensely fires moved across southern Indiana.

The need and benefits of periodic fire as part of forest health have been extensively documented in the Midwest and throughout the country. A major reason why prescribed fire has not been used previously at Brown County has been the park’s size. Access to remote and rugged backcountry has been a major deterrent.

Meetings with Fire Headquarters staff at Morgan-Monroe State Forest, DNR ecologists, resource specialists, the Nature Conservancy, and park staff, revealed that the park’s request for a burn treatment is not unusual. DNR prescribed fire is an annual (spring or fall) event on northern Indiana’s prairie remnants and savannas. Nature preserves on DNR lands in southern Indiana have been using prescribed fire to preserve plant habitats for many years.

Fire ecology, the study of fire and how natural systems respond, allows natural area managers to address biologically-rich sites.

When considering which park parcels to include DNR regional ecologist Tom Swinford said, “We need to burn the most botanically-rich sites we have.” Tom is familiar with these sites and the vegetation. He knows how burning promotes native vegetation and discourages exotic plants. The 350 acre proposed site was located away from buildings and facilities in a remote area. The land was accessed by horse and via pre-existing fire trails using 4-wheel drive fire vehicles and ATVs.

Professionally-trained fire professionals set and monitored small fires into ravines and ridge-tops where leaf litter, in some cases several feet thick, was reduced. Why reduce leaf litter? The reason relates to the native tree growth, specifically oak trees. The oak community (red, white, chestnut, etc.), a plant association coupled with hickories (shagbark and pignut), is an important component of Indiana’s hardwood forest. The “mast” produced by these nut-bearing trees is a vital food component to many forest wildlife. Many oak and hickory seedlings were seen scattered on the forest floor. The parent trees produced the acorns and hickory nuts overhead. What is missing is the representative sampling of young to middle-aged trees. The nuts germinate, but soon are shaded out. Shade-tolerant sugar maple and American beech displace oak and hickory since they can survive many years in these low light conditions. Not getting the light they need, the oak and hickory lose the battle.

How can prescribed fire be maintained? It takes serious study and knowledge of fire behavior. Once all weather, ground moisture, dried leaf litter information, wind speed, and fuel loads were determined on the burn day, a specific “Go” or “No Go” list was scrutinized by all in attendance. Hand-held drip torches allowed flames to be applied to a small strip of land, once prevailing winds were known. As the burn proceeded to a graveled or bare ground, previously-prepared fire line, it burned and produced a blackened strip of ground. Next another flame source was laid down to make the fire proceed up to the blackened area. “Burn to black” is a prescribed fire mantra. All who worked the prescribed burn (the park burn required approximately 20 individuals) kept this in mind.

Spring prescribed fire “burn windows” are utilized in early to mid-March ahead of spring bird nesting, reptile and insect emergence, and herbaceous plant growth. There should be only minimal wildlife disturbance from the burn.

Even Smokey Bear’s fire message of “Only YOU can prevent ‘forest’ fires” has changed to reflect the need for fire. The USDA’s Forest Service recognizes prescribed fire as a resource management tool. Smokey now says, “Only YOU can prevent ‘wild’ fires.” He is still mindful that burning brush or fencerows, a common “clean-up” practice in rural areas, can occasionally get out of hand. These become wild, escape quickly from their intended purpose, and can become deadly.

Watch for Brown County State Park interpretive programs that will allow visitors an up-close look at the prescribed burn site through spring and summer. Recovery is quick and blackened ground “greens up” rapidly, so visitors may be hard pressed to see where the burn actually occurred.

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