Buenger, Brent A. 2004. The Impact of Wildland and Prescribed Fire on Archaeological Resources . Final Report Prepared For: Wind Cave National Park. 161 p.
Natural fire is a ubiquitous phenomenon that has affected the archaeological record at many different levels throughout prehistoric and contemporary time. Knowledge of this important site formation process is essential to understanding the differential forces that have, and continue to, shape the archaeological record. This work examines the potential for prescribed and wildland fire to adversely affect the interpretive integrity and preservation of archaeological materials.
The issue is addressed through field-based experimentation, laboratory experimentation, and field-based sampling of burned archaeological sites. Field-based experimentation performed in conjunction with prescribed burn programs was conducted in a variety of fuel types including mixed grass prairie, mixed grass prairie/ponderosa pine, mixed conifer, riparian sagebrush, and piñon-juniper. The results of these investigations show that the important variables to consider when assessing the potential impact of prescribed fire on archaeological resources are: 1) fuel load; 2) fire behavior; 4) peak temperature and duration of heating; 4) proximity of artifacts to fuels; and 5) class of artifact.
Laboratory experimentation consisted of both trials in which selected archaeological material types were heated in a muffle furnace, and burned during wildland fire simulations conducted within a large combustion chamber/wind tunnel. The results of the furnace heating trials show that bone, shell, and certain varieties of chert are most prone to significant thermal alteration. The results of the laboratory wildland fire simulations illustrate the importance of fuel load, wind velocity, and flame angle as they relate to the significant thermal alteration of various archaeological material types. Bone, shell, chert nodules, quartzite flakes, and bottle glass were shown to be most susceptible to thermal fracturing.
The field-based sampling project was conducted at Mesa Verde National Park where 72 Pueblo I-III habitation sites burned during wildfire were sampled for observable fire effects. Vegetation type and fire severity were the most important variables affecting the thermal alteration of archaeological resources at the selected sites. The most pervasive form of thermal alteration observed was thermal spalling and fracturing of sandstone architectural elements. This was shown to have potential long-term negative implications for the preservation of sandstone architectural features at Mesa Verde.