Experimental Study of Fire Season and Frequency in South Florida Pinelands

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Fire is a major driving force in determining the structure and composition of subtropical vegetation. Prescribed fire constitutes one of the most pervasive management actions influencing the restoration and maintenance of the Greater Everglades Ecosystem. 

 

Aerial view of a prescribed burn

Aerial view of a prescribed burn

The Science Issue and Relevance: Fire is a major driving force in determining the structure and composition of subtropical vegetation. Prescribed fire constitutes one of the most pervasive management actions influencing the restoration and maintenance of the Greater Everglades Ecosystem. It is generally assumed that lightning-ignited fires were common in the spring, but there have probably been human-caused fires at other times for the last several thousand years. Since lighting-ignited fire cannot be allowed to operate naturally in south Florida, prescribed fire must be used to maintain these habitats. The seasonal occurrence and frequency of fire may influence ecological responses. This study will provide Interior land managers information on the effects of fire on south Florida ecosystems in order to better use prescribed fire to restore and maintain native plant communities and wildlife habitat.

Methodology for Addressing the Issue: We began a long-term study of fire season and frequency in Big Cypress National Preserve pinelands in 1996. The experimental treatments were combinations of three seasons (winter, spring, summer) and two frequencies (every 3 yr or 6 yr) of prescribed burns. Eighteen large (>50 ha) experimental units were established in old-growth pinelands, each with three 1.0 ha tree plots and five 0.1 ha understory vegetation plots, and the six treatment combinations were each applied to three of the experimental units. Over 16,000 trees were tagged, measured, and mapped and the herb and shrub layers sampled before the experimental treatments were applied. The treatment burns have been carried out by National Park Service fire management staff.

Researcher measuring burn results post prescribed fire

Researcher measuring burn results post prescribed fire

Post-treatment sampling after four of the short frequency burns and two of the long frequency burns was completed and continued over the next three years at which point will analysis of data to determine treatment effects occurred.

Future Steps: None, project completed. The results of the study will be used to either modify or validate current fire management strategies. The National Park Service will continue the experimental burning treatments to allow for future evaluation of longer term effects of fire regime. It is possible that results from the initial phase will suggest changes in timing of the experimental treatments going forward.

Products:

Adam C. Watts, Leda N. Kobziar, and James R. Snyder, 2012, Fire reinforces structure of pond cypress (Taxodium distichum var. imbricarium) domes in a wetland landscape. Wetlands, Vol 32, Issue 3, pp. 439-448.

John D. Lloyd, Gary L. Slater, and James R. Snyder, 2012, The role of fire-return interval and season of burn in snag dynamics in a south Florida slash pine forest. Fire Ecology, Volume 8, Issue 3, 14 pages.

Firefighter conducting a prescribed burn

Firefighter conducting a prescribed burn