On 18 March, a controlled burn again took place on 18 March at the Mason Farm Biological Reserve as part of the management strategy to promote the biological diversity of native plants at this nature refuge. During a controlled understory burn, the undergrowth of a defined area is set afire in a simulation of the wildfires that have historically been a part of meadow and forest ecology.
The area to be burned is prepared by clearing a broad border of flammable materials such as leaves and twigs. If there are trees or plants that should remain but that could catch fire, for example because there are vines going up their trunks, the area around them can be raked clear or sprayed with water, creating a firebreak.
A controlled burn requires permission from safety authorities and is monitored by a team of people, some of whom will ignite the fire and others who will patrol the perimeters and help ensure that the fire is quenched before leaving for the day. Duties are assigned during pre-burn briefings and team members have copies of maps showing which sections of the designated burn area are their responsibility. They carry out a radio check before the burn begins to ensure they can be in communication when needed.
At Mason Farm, the fires were ignited in lines through the use of a drip torch, which allows the person wielding it to direct a stream of flaming fuel to the area to be burned.
Perimeter and interior monitors use implements such as shovels, rakes, “fire flappers” (long-handled instruments with flexible ends to swat down flames and embers) and portable water sprayers to contain the burn within its boundaries.
The burn at Mason Farm was ignited first in a small patch so that the team could observe the speed with which the fire spread and burned the ground vegetation.
They also paid careful attention to the wind direction, which could transport embers and bits of burned debris away from the burn site.
Controlled burns are important in eradicating invasive plants (e.g., Microstegium vimineum, commonly known as Japanese stiltgrass) and enabling native plants to thrive. Some plants are fire-resistant and suffer little damage during a burn. A variety of grasses, flowers and trees need fire for their seeds to germinate, while other plants may need less dense areas as prime growth habitat. Some of the minerals contained in slowly decaying plant matter become soluble and more available in ash, contributing to quicker rejuvenation of the soil.
Some areas of the work area burned quickly and turned into smoldering ash that occasionally flared up with a rise or turn of the wind. During this burn, some patches did not catch fire; others at first appeared immune to the fire only to burst into flame after some time.
The flames could be quite beautiful and even mesmerizing as they flickered and flashed.
At times the wind turned and brought smoke in our direction, obscuring the view but then the wind shifted again and we could see the crackling, shifting fire on logs and stumps.
A concern for wildlife lovers is the possible demise of animals during a burn. Birds may lose nests but if the burn takes place outside the breeding season, the majority of birds can fly to safety. Many mammals can flee to other areas, while some reptiles and amphibians can burrow into the ground and survive. Occasionally, some animals may perish such as slow-moving turtles and arthropods (e.g., spiders) and insects. That is certainly a sad and regrettable outcome but team members sometimes can help rescue fleeing wildlife. During this burn, the marbled salamander larvae (Ambystoma opacum) continued to swim about placidly in a vernal pool in the woods across from the fire.
Overall, promoting a healthy environment for native plants not only helps restore the natural environment but is also important for wildlife species that depend on the fire-dependent plants for sustenance and habitat. Watching a burn can be an interesting and educational experience. People who want to participate in controlled burns can volunteer for this with the managers of preserved natural areas.