Why Fire?

by Dr. Sarah Treanor Bois
Director of Research & Education at the Linda Loring Nature Foundation

There has been a long tradition of fire ecology on Nantucket. While the amount of fire the Wampanoag used to alter the landscape is unclear, our Native American predecessors most likely used fire as a tool for clearing brush to support agriculture and other activities.

The modern equivalent of “controlled burning” started in the 1980s with Bill Patterson and Peter Dunwiddie, among other ecologists and land managers. It was informed and in coordination with the Nantucket Fire Department, but with little to no training in wildland fire involved.controlled burns | Nantucket, MA

Today’s controlled burns are generally called “prescribed fires.” A prescribed burn is the controlled application of fire to the land in order to accomplish specific land management goals. Today the Nantucket Prescribed Fire Program works diligently within a limited window of opportunity to meet Nantucket’s conservation and land management goals. The Nantucket Prescribed Fire Crew is a group of trained individuals of varying skill levels lead by highly trained wildland fire professionals. The Nantucket Islands Land Bank (Nantucket Land Bank) currently leads the prescribed fire crew on Nantucket, which includes on-island personnel from multiple organizations as well as professional burn crew personnel from off-island.

Why fire? Nantucket is known for its open grasslands, heathlands, and the majestic middle moors. These habitats, termed Sandplain Grasslands and Coastal Heathlands, are what ecologists call Early Successional Habitats. Classic Nantucket examples are found all along the south coast of the island: Smooth Hummocks, Head of the Plains, and Ram Pasture. These habitats are highly valued not only for their beauty, but for their biodiversity and association with a number of rare and endangered species.

Maintaining these grasslands requires disturbance in order to limit shrub and other woody vegetation encroachment. Historically, wind, salt spray, sheep, and the occasional fire created and maintained these habitats. Today, mowing, brush hogging, and grazing are just some of the tools used to create disturbance. Fire, however, has an ecological “natural” history and can be more successful in reaching the ecological management goals.

When a mower or brush hog mows over an area, all vegetation is cut equally. The results will be a uni-typic landscape as tall as whatever height the mower blade was set. When fire moves through an area, some plants (or “fuel” as they are called in fire ecology) burn faster or hotter than others, creating a mosaic effect. This results in patches of unburned vegetation among varying levels of burn across any unit.

Unburned patches can also act as refugia for plants, insects, and animals. The mosaic effect creates a habitat that is more diverse in plant heights, ages, and species. Fire can also produce some patches of bare soil. These patches are suitable sites for germination of many grass and wildflower seeds.controlled burns | Nantucket, MA

In addition to ecological and management goals, planned burning reduces fuel loads and can prevent future unplanned wildfires.

People may not realize that a significant amount of planning goes into prescribed fire. Years before a fire ever happens, a prescription is written for each potential “burn unit.” A burn unit is the particular acreage to be burned. It is often defined by boundaries such as a road, a mowed break, or a water feature such as a pond edge. Burn units are also put on a rotation, generally every 3 to 5 years on Nantucket, so that the area has a chance to recover before being burned again. Rotating when specific units are burned allows plants and animals to return to previously burned areas.

The prescription is a document which states the management goals (fuel reduction, ecological biodiversity, etc.), as well as the conditions under which this particular unit can and cannot be burned. It has information on wind directions, wind speeds, humidity, time of year, and many other factors. If any of these conditions are unacceptable on the day of a planned burn, they are considered to be “out of prescription,” and the burn will be postponed. Trained professionals write these prescriptions in collaboration with the landowners and the ecologists on staff. The document also has to be approved by local fire authorities.

It is only when all of the items in the prescription come together at the right time that a fire can happen. On the day of the burn, the burn boss starts with a “test fire.” This is a time when there is active fire on the ground and the leaders can see if the fire is behaving as expected. In addition to making sure everything is safe, ecological goals must be met.

Prescribed fire is conducted under the leadership of one or more experienced and certified prescribed fire leaders using professionally trained burn crew members. The training involved for prescribed fire is the same as that for wildland fire. In fact, some of Nantucket’s Prescribed Fire Crew members have been on wildfires in the western and southwestern US.

Some training has been conducted on-island, but many individual crew members have travelled off-island to Cape Cod, Plymouth, New York, and beyond for training opportunities.

The Nantucket Prescribed Fire Crew leaders work closely with the Nantucket Fire Department to ensure the safety and protection of surrounding resources. Nantucket Fire Department crew members are often on-site during the burn and many have participated as a training exercise.

There are many ways that the fire and smoke are kept under control during an active burn. First of all, the conditions are “in prescription.” Second, each unit has control breaks which are either roads or mowed breaks where fire is less-likely to cross. There are multiple engines on sight with water and hoses ready to be deployed. Trained crew members use special fire tools and backpack pumps with water to patrol and control the fire. The prescription also lays out backup plans to putting out fires, if necessary, and ways to get additional water resources to a unit.controlled burns | Nantucket, MA

We all know that Nantucket’s main economy is tourism. As such, the Nantucket Burn Program is limited in its capacity to burn. Research shows that growing season burns (fire generally during the summer) have the greatest ecological benefit to reducing woody shrub cover and promoting grassland and forb growth. However, Nantucket is not allowed to burn between Memorial Day and Labor Day. The 2018 Nantucket wildfire season runs from October 1 to November 16. Permitting for this window has been obtained from the Massachusetts Department of Environmental Protection. During that short time, the Nantucket Islands Land Bank Commission plans to burn Head of the Plains (south and west of Sanford Farm) and Smooth Hummocks (east of Cisco & west of South Shore Road) given proper weather conditions.

Fire is a natural management tool for effectively reducing woody shrub encroachment and promoting grassland and wildflower growth. Many heathland species bloom and grow profusely after a wildfire and some species require fire for germination. Wildlife such as deer and rabbits can run faster than the fires burn, and small mammals and reptiles seek shelter underground. Overall, the resulting sandplain grassland and heathland mix are beneficial to the entire ecosystem.

If you see smoke on the horizon, report it to the Nantucket Fire Department: they will know if the Nantucket Prescribed Fire Crew is burning on any given day. For safety, stay away from active fires, even if being conducted as part of a prescribed fire event. If you have questions about the prescribed fire program, call Eric Savetsky at the Nantucket Land Bank: 508-228-7240.