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Prescribed burns

For thousands of years, fire has played an important role in shaping the landscape of south Florida. Historically, fires usually occur during the summer-wet season, started by lighting from thunderstorms. Because the ground was wet, the intensity and severity of the fire was limited.

The native plants evolved adaptations to help them survive fire and even proliferate because of fire. Branches and needles of the mature Slash Pine are high above the ground where flames cannot reach them, and the bark of the tree acts as a fire retardant and protects the living wood inside from the flames. The trunks of the Cabbage Palm serve the same function. The Saw Palmetto's main trunk is below the ground level where fire cannot reach it and it begins to send out new leaves within days after a fire has burned over it.

This natural cycle changed as man altered the landscape of South Florida. Large areas were drained for human use, and the natural resistance to fire was lost. Most fires are now caused by arson and other human activities, and many of these occur during the spring dry season. Because of the dry conditions, fires during this season tend to be more intense and cause greater damage to the plants and soil.

One way of decreasing the damage done by wild fires is to periodically burn an area in a controlled fashion. By doing this, the amount of fuel that is allowed to build up is limited. With a limited fuel supply the fire is not as intense and there is less damage to the plants and soil. The permitted, prescribed burns are done every four to six years, mimicing what would have been the natural cycle.

Fire releases nutrients that were trapped in the dead plant material, making these nutrients available to the remaining plants much quicker than they would through decay. The new growth of plants in the enriched soil also attracts native wildlife.

Day 0 (top): A controlled burn exhausts the accumulated fuel load on the ground.

Day 11 (center left): The land appears barren, but already saw palmetto are sending up new shoots and florescences.

Day 40 (center middle): Saw palmetto has leafed out and the grasses, ferns, and other ground plants send up new growth from the roots.

Day 68 (center right): Growth continues, giving the landscape a green appearance. Deer are among the first mammals to return, browsing on the tender new growth.

Day 152 (bottom): Other than darkened trunks on the pines, evidence of fire has disappeared. The native plants are growing more vigorously and are healthier than before while the fuel load of dead branches and fronds, leaves and needles, and shrubby exotic plants are gone.