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​Prescribed Fire: Using Technology and Aircraft to Restore Habitats and Protect Communities​



Image of helicopter flying over natural area


​Prescribed fire is an essential management technique for the restoration and maintenance of the native habitats in our natural areas, but also for the safety of the communities that surround these areas.  It is important to remember that prescribed fire is implemented in very specific conditions in order to complete the burn in the safest way possible.  Without prescribed fire, fuel (anything that grows and will burn…like grass, palm leaves and trees) will continue to build up over the decades, and if it is ignited and becomes a wildfire, there is the potential for the fire to become out of control and threaten surrounding property, homes and infrastructure.  Here we take you on a photo-story of a large prescribed fire completed in March of 2021 at Pine Glades Natural Area.  Utilizing a partnership with Palm Beach County Environmental Resources Management (ERM) and South Florida Water Management District (SFWMD), we were able to successfully manage and restore the fire-interval on 1600 acres in one day. ​​​


​Image of Staff Briefing Team Prior to Burn​​​

​The Burn Briefing – ERM Prescribed Fire Manager Harper Carroll begins each burn with a burn briefing.  During this meeting, all staff on the burn team review the “prescription” for the day’s burn, including the necessary and forecast weather conditions (such as temperature, humidity, wind speed, wind direction, dispersion index, moisture, and many others), firing techniques and patterns, organizational charts, ecological and public safety goals, and contingency and emergency medical plans.​​

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Image of Burn Crew Conducting Test Burn​​​
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​The test fire: After all the planning that goes into making a prescribed fire possible, and after the weather is confirmed the morning of the burn, followed by receiving authorization from Florida Forest Service to proceed, each and every burn starts with a test fire.  The test fire is a small fire ignited at the point of the burn unit furthest downwind.  This allows fire managers to monitor the small fire with suppression crews present, to ensure the fire is “acting” as anticipated by the burn manager based on conditions.  If not, the suppression crews will extinguish the fire and the burn may be delayed or cancelled.  If (as in almost all cases) the test fire behaves as anticipated, the burn manager will declare the test fire complete and proceed with ignition of the burn.​​

Image of Burn Crew Igniting Burn to Make Black Line​

With the test fire complete, each fire begins with “building a black line” in which to burn into later in the burn.  The black line is built by igniting a backing fire on the downwind line of the burn unit.  This “backing fire” is burning against the wind, resulting in a low-intensity and easily controlled fire.​​

​Burn Crew Conducting Fire Suppression

Suppression crews follow the ignition team and monitor the line to ensure no embers cross the fire line (a dirt road or line with little or no fuels that acts as a fire-break and demarcates the burn unit from surrounding management units within the site).  ​


Image showing backing fire close up

This ba​cking fire continues to be built by ignition teams to create a wide are​​a of “black” that now has no fuels left to burn.  This creates a safe zone to burn into as the rest of the ignition pattern is completed throughout the burn.  

​Image showing ignition spheres close up

Aerial burns are prescribed burns where the majority of ignition is done b​​y helicopter which allows staff to more efficiently and safely burn a much larger area than performing ignition on the ground alone.  While the ignition and suppression crews build the black line, the burn manager begins to prepare the aircraft, fire equipment and coordinate with the pilot while monitoring the progress of the black line over the radio.  This image shows PBC ERM burn manager Harper Carroll preparing the ignition spheres to load into the aerial ignition device.​​​

 Burn Crew Loading Ignition Spheres into Helicopter​

Gene Colwell, senior scientist with South Florida Water Management District (SFWMD), loads the ignition spheres into the aerial ignition device.  The spheres are loaded with potassium permanganate.  When the operator drops them from the ignition device, it injects the spheres with a small amount of ethylene glycol.  This creates a chemical reaction within the sphere, and several seconds after the sphere hits the ground, it catches fire (similar to an emergency flare) and burns for approximately 2 minutes, igniting the grass and other fine fuels where it landed. ​

​Helicopter in Flight

SFWMD senior scientist Gene Colwell operates the aerial ignition device while harnessed into the helicopter’s restraint system (note the ignition sphere dropping towards the ground).
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By manually firing each ignition sphere, the fire managers can precisely control the speed and intensity of ignition and the overall fire behavior.  Here, ERM burn manager Harper Carroll sits next to the pilot utilizing a tablet loaded with a GPS compatible map that shows the burn unit in real time, as well as their flight tracks and ignition patterns.  Harper and Gene communicate constantly between each other and the pilot to adjust firing technique based on the habitats and fuel loads below.


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The helicopter continues its grid pattern as the suppression crews on the ground monitor the perimeter of the unit.  ​

Image of prescribed fire from afar ​​

From afar, the resulting controlled fire looks quite intense, creating a large smoke plume.

Image of prescribed fire closer up

But up close, it becomes much more obvious that the fire is controlled, low intensity and is implemented with precision. 

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description of the image

​This shows the map used by the burn managers in the helicopter, along with the helicopter’s flight patterns.  The wind was coming from the east, and so the tracks began on the left side of the map, progressing slowly to the east, so the fire on the ground worked against the wind in a low-intensity manner.  The map also easily shows the large wetland areas (darker areas on the map) which continue to hold water and act as “safe zones” for wildlife to shelter in during the fire.

​Image of fire as seen from above

​Finally, the view from the air…here you can see the grid patterns of “spot fires” created by the aerial ignition pattern.  The spot fires burn out slowly, allowing the incredible array of wildlife that calls Pine Glades Natural Area home to move away and take shelter.  It is incredibly rare to see wildlife mortality from a prescribed fire (it can be devastatingly different during a wildfire situation, where dangerous weather conditions can carry a fire much faster than ever would be implemented during prescribed fire activities).  In addition, the benefits to the land allow many species to thrive in this naturally fire-maintained ecosystem. 


​Image of bobwhites foraging along the ground


​A fabulous example are northern bobwhites.  These small ground birds are also known as the “firebird” because they are so reliant on grassy, open flatwoods and prairie environments.  Their habit​at has shrunk dramatically in recent decades due to both development of ranchland and fire suppression.  The reintroduction of fire management to Pine Glades has now allowed the birds to flourish and reproduce here once again (the birds photographed here are juveniles!).​​
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​Image of a Meadowlark Sitting on a branch

​Another bird that, while considered common, is in decline due to habitat loss and fire suppression is the eastern meadowlark.  These stunning birds rely on the same habitats as the bobwhites, and can often be seen at Pine Glades perched on a pine tree brand or the top of a shrub singing loudly.  ​

​Image of a Sandhill Crane Laying Down

​​Last, a bird that many are often worried about during fire activities are our beloved sandhill cranes.  This bird sat on a nest during the fire…the nests are located in wetlands that contain standing water where they build a mound of grass above the water.  This protects them from both predators as well as fire.  When they have babies, called “colts”, on the ground, the low-intensity and slow moving prescribed fire gives them ample time to shepherd their young into the safety of a nearby wetland.  Often in the days and evening hou​r​s after a prescribed fire, you can see cranes leading their colts into the burned area where they feast on insects and other food sources. ​
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