The Effects of Prescribed Burning on Cultural Resources

Our knowledge of fire effects on cultural resources comes from field investigations and laboratory experiments. Previous studies have documented the condition of artifacts, historic sites, and significant landscapes after a fire event, but the impacts of fire on cultural resources are underestimated due to the shortage of scientific research (Lentz, Gaunt, and Wilmer 1996). More research is needed to determine the effects of prescribed fire on cultural resources since most previous research has focused on wildfires.

Since prescribed burning is such a common tool for managing southern woodlands, its impacts on cultural resources are a topic of great concern (US Army 1989). While prescribed fires may not have as many direct effects on cultural resources as wildfires, due to their lower intensities, considerable damage may still occur if burns are not carefully planned. For example, fire may burn unknown historic wooden structures, artifacts above ground, and plow lines. Carefully planned prescribed burns can minimize these adverse impacts to cultural resources. For example, the burn may be routed around a gravesite or the footprint of a historic home site. Federal and state legislation and guidelines for protecting cultural resources specify methods for protecting cultural resources from damage prescribed fire in cultural resource sites.

Prescribed burning can have beneficial effects, enhancing resources valuable to contemporary cultures. Prescribed fires can be used to maintain or restore some cultural landscapes, or geographic areas meaningful to a community (Foppes 2001). This is true where people collect fire-dependent plants or plants that grow in recently burned ecosystems (Hunter 1988). Another example is an effort to restore the Chickasaw-Blackbelt Prairie, a 190 acre landscape on the Natchez Trace Parkway in northeast Mississippi. Prior to European arrival the Chickasaw Indians used fire to manage a landscape mosaic of blackjack oak (Quercus marilandica) or post oak (Quercus stellata) woodlands and grasslands. Today, the program is using prescribed burning to achieve its objective to restore an ecosystem because of its cultural-historical value. Other sites with significant cultural resources may benefit from projects that use prescribed fire to restore burned ecosystems. For example, attempts to rehabilitate a watershed may stabilize riverine soils. The prohibition of motorized vehicles from burned areas may prevent further damage to resources (Swan and Francis 1991).

Direct and Indirect Effects of Fire on Cultural Resources

Fire is one among numerous ecological and cultural processes that affect cultural resources and the contexts in which they are located. Human activities that affect cultural resources include agriculture, mining, industry, recreation, development (above and below ground), flood control, and artifact collecting (Nickens 2000). The activities of fire personnel and resource investigators can also affect the condition of artifacts and their interpretation. For this reason, guidelines for protecting cultural resources are available to fire personnel.

Fire can change the value of cultural resources. The ability of researchers to interpret the significance of a cultural resource for a previous or current society is diminished anytime it is altered by fire (Lissoway 1990). Valuable clues about previous lifeways may be lost when the footprint or structural beams of a historical house are burned because these resources are non-renewable. In cases where individual artifacts within a site are damaged, it might complicate the discovery or interpretation of the site as a whole. Rearranging the spatial relationship of materials within a site, as when the soil is disturbed, diminishes the ability of researchers to interpret human thought and behavior. The sites that are or that contain cultural resources and the environment surrounding a resource are the contexts for artifacts, structures, ceremonies, and other meaningful objects and activities.

The effects of fire on cultural resources vary. Cultural resources in areas where fires are more common, have been exposed to more heat treatments than cultural resources in areas where fire is less common. Low intensity fires – such as those lower than 212°F at a depth of 1-2 cm – have less adverse effects on many cultural resources than high intensity fires – lower than 662-842°F at 1-2 cm and greater than 212°F at 5 cm (California Department of Forestry 1983).

Some of the factors that cause variability in fire effects on cultural resources are:

• materials used to construct the resource conditions (moisture, type) affecting fire behavior (fuel, weather, topography)
• events

Some of the direct effects of fire on cultural resources are:

• materials to the staining structure breaking in spatial arrangement objects chemical composition an object (complete or partial) of archaeological dating
• indicators in natural materials

• ratio analysis hydration
• thermoluminescence
• alteration of archaeological materials

Some indirect effects of fire on cultural resources are:

• suppression
• fire construction line disturbance soil by context artifact gasoline and foams, retardants, artifacts equipment mechanized crew of in to

Post-fire activities can directly and indirectly impact cultural resources. Some of the restoration efforts that alter resource integrity are replanting, berm leveling, salvage logging, stream stabilization, Off-Highway Vehicle barriers, and water control measures (Machlis 2002; Swan and Francis 1989). Salvage logging operations can be destructive when they involve large equipment moving on unstable ground or when they involve operations near damaged resources that may be newly exposed (Swan and Francis 1991). When dozers are used in fire suppression, the blades and wheels can damage sub-surface and surface materials (NWCG 1995). The construction of helipads can cause displacement of materials, exposure of sub-surface materials, and can conceal sites by covering them with dirt or debris. Damage can be mitigated if sites are mapped and marked or otherwise protected from logging equipment and timber felling.