Fire Lines Newsletter Volume 12 Issue 4
Research Brief
The interaction of natural disturbances that affect ecosystems within a narrow span of time can influence the outcomes of those disturbances. The authors of a study recently published in Trends in Plant Science looked at coastal woody ecosystems affected by both tropical cyclones and fires (Ibanez et al., 2022). Historically, fires and cyclones have been drivers in the creation, maintenance, and transition of open-canopy and closed-canopy biomes in some coastal areas. However, human activity is altering the natural cyclone-fire interactions of coastal woody ecosystems and their responses to these disturbances.
Cyclone-Fire Interactions in Coastal Woody Ecosystems
In closed-canopy forests where fire is not a regular occurrence, tropical cyclones can increase fire frequency and intensity. Directly, tropical cyclones can increase the amount of litter available as surface fuels and can open the canopy, creating a drier fuel bed and promoting the growth of understory fuels. Indirectly, tropical cyclones may increase the occurrence of fires through post-storm human activities due to debris burning and land clearing. When wildland fires occur prior to tropical systems, they can damage trees, reduce stand density, and indirectly reduce wood strength by moderating in-stand competition. Open, low-density stands may be more susceptible to damage from tropical cyclone winds.
In areas frequently affected by tropical cyclones and fires, the effects of the disturbances interact to create open-canopy savannas and woodlands. The winds from tropical cyclones increase surface fuels which carry fire when ignitions occur. Regular fire controls the growth of low vegetation and consumes fuels so that subsequent fires are lower in intensity. Human activity is disrupting these interactions, especially through alterations of fire regimes, affecting fire-adapted species and potentially shifting open-canopy biomes to closed-canopy forests.
Changes In Cyclone-Fire Interactions
While tropical cyclones and wildland fires are natural disturbance events for many ecosystems, human activities such as fire suppression and climate change, may be altering the interactions of the disturbances. Human-caused changes in disturbance frequency and intensity may be impacting the resilience of southeastern ecosystems.
There has been progress in the collective mission to increase the use of prescribed fire in the southeast and restore natural fire regimes on the landscape. At the same time, the region is increasingly affected by hurricanes with greater intensities and more frequent lightning strikes as a result of climate change. Increased frequencies of tropical cyclones, coupled with greater likelihoods of fires, could drive pine savannas towards treeless prairies. It will be important to incorporate into land management decisions the potential for interactive effects between fire and hurricanes. Ibanez, T., Platt, W. J., Bellingham, P. J., Vieilledent, G., Franklin, J., Martin, P. H., Menkes, C., Pérez-Salicrup, D. R., Russell-Smith, J., & Keppel, G. (2022). Altered cyclone-fire interactions are changing ecosystems. Trends in Plant Science, 27(12), 1218-1230. https://doi.org/10.1016/j.tplants.2022.08.005
SFE Updates
Prescribed fire and invasive species control are two common land-management actions in the Southeast, so it is important that land managers have a solid understanding of their interactions and how they affect the surrounding ecosystems. Written by Deb Stone and Michael Andreu with the University of Florida School of Forestry, Fisheries and Geomatic Sciences, this fact sheet describes several common invasive plants and their basic life history, how they impact fire ecology, how they respond to fire, and management implications. The species discussed include cogongrass, Chinese tallow, and climbing ferns.
(Fact sheet published by UF IFAS Extension)
