Prescribed Fire on Nantucket
The following text was taken and modified from a publication by
the Fire Management and Research Program of The Nature Conservancy
Fire is an often misunderstood management practice that most people have been trained to think of as destructive to property, habitat, and wildlife. However, it is a natural process that has been a part of the environment for thousands of years, and can still be used under very controlled circumstances to produce desirable ecological goals and prevent uncontrollable wildfires. The following explains why Nantucket's conservation land managers conduct prescribed burns, the precautions that are taken to ensure that they are done in a safe and controlled manner, and the benefits of utilizing this management technique.
Why is prescribed fire used?
Fire is an important process in maintaining habitats for many species of plants and animals. Historically, lightning caused many fires. Native Americans also burned areas to clear them for agriculture, improve forage for game species, stimulate berry and acorn production, and to ease travel. Many plants and animals became dependent on periodic fires for their reproduction, growth, and survival. Throughout much of the country, the development of towns, roads, and farmlands, combined with effective fire suppression, has stopped fire from moving across the land as it once did. Prescribed burning is now used to return fire to these areas in a controlled fashion so that it may continue its vital role. Prescribed burning also reduces heavy buildup of dead wood and other debris, thereby decreasing the threat of catastrophic wildfire.
What is a prescribed burn?
Prescribed burning is the controlled application of fire to the land, used to accomplish a specific conservation or land management goal.
Who conducts the prescribed burn?
Prescribed burns are conducted by trained fire professionals who have studied fire behavior and fire control techniques to ensure the safety of the burn crew, nearby residents, and private property. In New England, burn professionals are associated with a variety of organizations and agencies, including the National Park Service, The Nature Conservancy, University of Massachusetts, the Massachusetts Division of Fisheries and Wildlife, the U.S. Forest Service, the Nantucket Islands Land Bank Commission, the Nantucket Conservation Foundation, the Massachusetts Audubon Society, and the Nantucket Land Council. Prescribed burns are conducted in cooperation with federal, state, and local fire management agencies.
What is a burn prescription?
The key to a safe and effective burn is planning. Before fire is applied to the land, a rigorous planning process is undertaken to determine the acceptable conditions under which the burn will be conducted. The conditions are written up in a document called a "prescription," which includes expected fire behavior, relative humidity, wind speed and direction, air temperature, and dryness of the vegetation, along with a plan describing how the fire will be ignited and contained. If the weather conditions are unacceptable on the day of a planned burn, they are considered to be "out of prescription," and the burn will be postponed. The prescription planning process ensures that the burn is approved by the local fire control authorities and all burning permits have been obtained. By following a prescription, fire managers are able to accomplish the objective of the burn and provide for public safety.
How is the fire kept under control?
Fire breaks, which surround the area to be burned, prevent the fire from moving onto adjacent land. A fire break may be a road or trail, a mowed or plowed line, a natural feature such as a stream or pond, or a recently burned area. Water or fire retardant foam may also be sprayed down to create a fire break. During the burn, fire breaks are patrolled by burn crew members who use specialized fire tools, backpack water pumps, and water-carrying pump trucks to ensure that the fire does not cross the fire break. Crew members wear special fire resistant clothing to protect themselves during the burn.
What about the smoke?
Controlling where the smoke will go is an important part of every prescribed burn. Before each burn, fire managers look carefully at what they plan to burn and the proximity of houses, roads, airports, and other smoke-sensitive sites. This information is incorporated into the burn prescription so that the burn will only be conducted when winds will move the smoke up and away from populated areas and keep smoke off highways, runways, etc. Periodic prescribed burns prevent heavy brush accumulation, which would send a larger amount of smoke into the air if a wildfire were to occur.
Where are prescribed burns conducted?
Each year, prescribed burns are conducted at a variety of sites across the country by government agencies and private organizations. Burns can range in size from thousands of acres in remote locations to small burns of just a few acres in more urban landscapes. In southeastern New England, burns are regularly conducted on Cape Cod, the Elizabeth Islands, Martha's Vineyard, Tuckernuck Island, and Nantucket in order to perpetuate rare habitats that are limited to this region. On Nantucket, prescribed fire is implemented on numerous properties across the island owned by the Nantucket Conservation Foundation, the Nantucket Islands Land Bank Commission, and the Massachusetts Audubon Society.
How do prescribed burns benefit the land?
Nantucket's unique heathlands and grasslands contain many rare and endangered species of plants and animals. Plants such as bushy rockrose, St. Andrew's cross, eastern silvery aster, New England blazing star, sandplain flax, and broom crowberry do best growing in nutrient-poor, sandy soils that receive full sun. Periodic disturbance, to which most of these species are adapted, keeps taller shrubs and trees from shading and out-competing these plants. Two endangered birds of prey, the northern harrier and short-eared owl, utilize open grasslands to hunt their preferred prey species, the meadow vole.
Grasslands and heathlands on Nantucket are largely the result of human activities. They were created by centuries of land use practices that included harvesting wood for home building, ship construction, and fuel, clearing land for agriculture, and long-term grazing by sheep and other livestock. Most of these activities have ceased over the last century, allowing scrub oak, pitch pine, and other tall shrub species to encroach upon these habitats. If left unchecked, this process will result in these areas being overgrown, and the rare species associated with them will disappear due to lack of suitable habitat.
Fire is a natural and effective means of managing grasslands and heathlands. Many heath species bloom profusely following burns, and some actually require fire to reproduce. Grasses, sedges, and perennial wildflowers are not damaged by burning because they have extensive, below ground root systems. Although most shrubs are capable of re-sprouting after a fire, this management practice top-kills them and prevents them from out-shading and overtaking heathland plants.
Unlike mowing, which has a uniform impact over the area being managed, fire usually produces a patchwork of burned and unburned habitats because of variability in its temperature, intensity, and rate of spread. As a result, older, unburned plants are distributed within newly-burned habitat, creating a mix of cover and forage conditions that benefit many species of wildlife.