Fire and the Southern Appalachian Forests
The Need for Research and Monitoring Programs
A History of Fire Suppression
The massive wildfires, which have recently occurred in the western United States , have prompted us to reexamine our 80-year history of fire suppression. We are beginning to accept the natural role fire plays in a landscape, promoting ecosystem health by reducing fuel, releasing nutrients, and maintaining a natural balance. Historical fire regimes are beginning to be restored across the US in order to reduce fuel loads. However, though fuel reduction models may fit western US ecosystems, the ecosystems of the southern Appalachians have a more complex relationship with fire. In the Southeast, where high decomposition rates naturally reduce fuel loads and wildfires pose less severe threats, fire's role in maintaining an ecological balance through releasing nutrients, removing invasive species, and promoting diversity is very important. Yet this is only the case in fire dependent ecosystems. Many ecosystems of the Southeast, such as hardwood cove forests and riparian hemlock forests support fire intolerant species. The role of fire in the southern Appalachians must be fully understood and the appropriate scale and extent of fire determined, so under abuse of fire in the past does not contribute to an over abuse in the future, and the rich diversity of ecosystems in the Southeast is preserved.
The Reintroduction of Fire into the Southeast
In response to the national fire plan and the Healthy Forest Initiative we are seeing dramatic increases in fire projects in southern Appalachian forests.
The recent fires on our southeastern National Forests have been conducted under the guise of fuel reduction. However, fuel may actually be increased after the burn. Though the litter layer is effectively removed, the reintroduction of fire leaves standing dead rhododendron. It could be argued that the litter layer is the fuel that carries the fire across the forest, however, the dead understory could provide ladder fuels, and cause more intense burning and more ecological damage than previous natural fires. It seems reasonable to conduct follow up burns, before the litter layer returns so as to further reduce fuels. Since fire has been excluded from these landscapes for quite some time, it may take a few consecutive burns before the ecosystem balance is restored. Further research in this area is greatly needed.
A much more logical reason to initiate prescribed burning seems to be a case for forest health restoration, particularly understory reduction. In some areas rhododendron and mountain laurel are extremely dense, and it is difficult for seedlings to become established. Herbaceous species richness and diversity also suffer under dense rhododendron canopies (1). Pine hardwood ecosystems have also taken a hit due to fire exclusion. Table mountain pine, whose serotinous cones need bare soil for regeneration, have been in a state of decline (2). It is still unknown as to what the appropriate fire regimes to restore these ecosystems are and how the pines have responded to current prescribed burning techniques (3).
The landscape burns, which are conducted with single ignition points along a ridgetop and mimic natural lightening strikes, create a lot of heterogeneity in burn severity, as fire is allowed to naturally extinguish itself as it burns downslope (4). Variation in the burn seems to correlate with vegetation type, slope, aspect, and topographic curvature. Transitions between medium and low intensity burns are often abrupt, with the fire dying out completely as it reaches wetter areas. In the unburned areas, herbaceous layers are often extensive, with many fire intolerant species present such as lilies, snakeroot, wild yam, mandarin, violets and ferns. This brings up the question of what would happen if fire was forced into these areas through prescribed burning? If a series of burns were conducted to reduce the now standing dead understory, would the fire conditions be different and would previously unburned areas be at risk? Since so little is known about the historical fire regimes of the southern Appalachians , these types of questions can only be answered through a monitoring program. And with such extensive burning occurring in the national forests, these research opportunities should not be wasted (see more on burn severity).
The Need for Research and Monitoring and SAFC's Call to Action
Here's Hugh taking some pictures of a burn project on the Cherokee National Forest.
Flight courtesy of Southwings.
Currently the Forest Service is doing very little monitoring. Plots have been set up, however they are not specific to any fire, and are located on fire-tolerant xeric sites, collecting no data on fragile mesic communities. Pre-burn vegetation type is not recorded, nor where the burn actually occurred, nor what vegetation responses occur post-burn. Recording this data is essential to understanding the role fire plays in the Southern Appalachian ecosystems and how our silvicultural treatments are affecting current balances. We have many questions on fire's role in the Southern Appalachians.
The Southern Appalachian Forest Coalition (SAFC) has been working to further the understanding of fire in the Southern Appalachian ecosystems. As the Forest Service monitoring plan does not answer the question of where fire actually occurs, SAFC seeks to document fire occurrence and the extent to which mesic communities are impacted. Currently, we are collecting post burn data on burn severity and hope to create a model predicting fire response to a number of variables including vegetation type, aspect slope, elevation, and topographic curvature. This model should tell us important relationships between fire and ecosystem type, and help create a case for the appropriate role for fire. The overall goal should be ecosystem health and the only way to assess this is monitoring ecosystem response to treatments over time. SAFC hopes that its work will lead to more extensive monitoring by the Forest Service, as the wealth of information available on these burns, and the ease of which it can be accessed becomes apparent.
1 - Van Lear, D., Vandermast, D., Rivers, C., Baker, T., Hedeman, C., Clinton, D., Waldrop, T. (2002) American chestnut, rhododendron, and the future of Appalachian cove forests. Outcalt, Kenneth W., ed. 2002. Proceedings of the eleventh biennial southern silvicultural research conference.Gen. Tech. Rep. SRS-48. Asheville , NC : U.S. Department of Agriculture, Forest Service, Southern Research Station. 622 p.
2 - Vose, J., Swank, W., Clinton, B., Hendrick, R., Major, A. 1997. Using Fire to Restore Pine/Hardwood Ecosystems in the Southern Appalachians of North Carolina . Proceedings-Fire Effects on Rare and Endangered Species and Habitats Conference, Nov. 13-16.1995.Coeur d'Alene, Idaho.0 IAWF, 1997
3 - Waldrop, T., Brose, P., Welch, N., Mohr, H., Grey, E., Tainter, F., Elllis, L. 2003. 2003. Are crown fires necessary for Table Mountain pine? Pages 157-163 in K.E.M. Galley, R.C. Klinger, and N.G Sugibara.(eds.). Fii Conference 2000: The First National Congress on Fire Ecology, Prevention, and Management. Miscellaneous Publication No. 13. Tall Timbers Research Station, Tallahassee , FL
4 - Elliot, K. J., Hendrick, R. L., Major, A., E., Vose, J. M., Swank, W. T. (1999) Vegetation dynamics after a prescribed fire in the Southern Appalachians . Forest Ecology and Management. 114 : 199-213