The following case study is part of a forthcoming NPS handbook on climate change entitled “Climate Change and Cultural Resources: Impact Assessments and Case Studies.” The original author is Caitlin Smith.
With its lush valley meadows and craggy snow capped peaks, Rocky Mountain National Park is best known for its remarkable scenic beauty and mountain recreation. However, the park is also home to a vast array of natural and cultural features that tell the story of past human activities in the Colorado Rocky Mountains. Hundreds of prehistoric and historic archeological sites are located in the park (NPS.gov 2006), testament to the presence of Ute, Arapaho, Cheyenne, and Shoshone tribes, as well as white trappers, explorers, market hunters, and ranchers (Brett 2003). These eloquent physical remnants of the human story are an integral part of the park’s cultural landscape, but are difficult to manage in a dynamic landscape system with varied and sometimes conflicting preservation goals. In the case of fire, it is often the indirect effects of fire management (e.g., wildfire suppression and prescribed burns) that cause the most damage to delicate cultural resources, rather than the fire itself (Buenger 2003; Brunswig et al. 2010; Ryan 2001). Therefore, with more frequent fires occurring in Rocky Mountain as a result of climate change, it is important to consider how the secondary effects of fire management may increasingly impact its cultural resources and values.
The landscapes of Rocky Mountain National Park have unfolded over time, reflecting changes in climate and geomorphology. Recent disruptions to the earth’s climate are accelerating, causing major shifts to the park’s landscape and resources. For the western mountains bioregion, scientists anticipate continued increases in temperature, more winter precipitation falling as rain, reduced winter snowpack and earlier runoff, species range shifts, and increasing severity of drought and wildfire (Loehman 2009). Changes in temperature and water cycling lead to increased size, intensity, and duration of fires, posing a significant threat to park cultural resources (Saunders and Easley 2006). There is a very strong correlation between high spring and summer temperatures combined with early snowmelt, and severe wildfires. In addition, mountain pine beetle and blister rust are causing higher tree mortality and more standing and fallen fuels (Ehle and Baker 2003). The northern Rocky Mountain region has experienced the largest increase in climate related wildfires in the United States (Saunders and Easley 2006), and in Rocky Mountain National Park scientists predict that the number of lightning fires could increase by 50 to 92% in the next 100 years.
Archeological features and historic structures at Rocky Mountain National Park are at risk to wildfire damage- both primary (the fire itself) and secondary (unintended fire management damage). Aboriginal wood structures such as culturally peeled trees, wickiups, platforms, sweat houses, and animal runs/traps are particularly vulnerable to fire due to their flammable materiality and location in fire-prone forested montane zones (Veech 2010, Brunswig et al. 2010). Direct exposure to flames causes irreversible fire effects to cultural resources including but not limited to cracking and spalling, discoloration, chemical breakdown (calcination and carbonation), deformation, the loss of diagnostic characteristics (e.g., loss of date-able organics and hydrated obsidian surfaces), as well as outright destruction and loss (Buenger 2003; Ryan 2001; Ryan and Jones in press). Surprisingly, the most severe damage often comes from physical disturbance related to fire-fighting. Fire lines, staging areas and helipads, the movement of heavy vehicles, and fire-fighting chemicals can all damage cultural resources (Buenger 2003; Ryan 2001). The same actions have also been known to accelerate soil erosion after a fire (Brunswig et al. 2010). In addition, ground-disturbing activities associated with prescribed fire and with post-burn rehabilitation can also damage cultural resources.
Shallow archeological deposits in the park are vulnerable to surface disturbance by vehicles or temporary access road construction, which can crush culturally and temporally diagnostic artifacts such as projectile points, while dislocating and mixing surface artifact assemblages. Construction of fire lines through sites can destroy their archeological integrity by disturbing buried cultural levels and features (Brunswig et al. 2010). This permanently erases spatial and temporal relationships between artifacts and features, foreclosing our ability to understand the past. Fire retardant is documented as causing damage to cultural resources in Rocky Mountain National Park and other western parks (Brunswig et al. 2010). A U.S. Forest Service study found that fire retardants cause thermal shock to fire-heated stone artifacts and features, coat stone artifacts with a chemical film that destroys organic residues, introduce destructive acids into archeological bone and pottery, and adversely affect historic wooden structures and artifacts by staining the wood and accelerating decomposition (Brunswig et al. 2010).
In summary, fire damage to cultural resources occurs in three phases: 1) higher temperature and drought lead to 2) more frequent and intense fire regimes which lead to risk of direct impact and 3) fire management actions that may also impact cultural resources. Given this relationship, climate change is reframing the way parks think about cultural resource management. Rocky Mountain National Park has responded to recent climate-driven outbreaks of wildfire by initiating documentation programs to virtually salvage at-risk resources. Through a Colorado Plateau CESU partnership under the direction of NPS archeologist Dr. Andrew Veech, the University of Pennsylvania will document 19 American Indian wooden structures at Rocky Mountain National Park (as well as 19 more at Grand Canyon National Park). Each structure is captured using high-resolution, 3-D digital models, with the objective of producing virtual models that will allow them to survive in perpetuity, albeit in digital format (Veech 2010).
This form of documentation complements efforts to communicate about climate change and cultural resources to park managers and fire fighters on all levels. In order to best protect both the natural and cultural resources that make Rocky Mountain National park a place of such spectacular beauty and significance, climate change education and communication must go hand-in-hand with documentation as the park takes action to manage the effects of climate change.
1. Buenger, Brent B. The Impact of Wildland and Prescribed Fire on Archaeological Resources. Dissertation submitted to the Department of Anthropology, University of Kansas, 2003.
2. Brett, John A. “Ethnographic Assessment and Documentation of Rocky Mountain National Park” University of Colorado at Denver, 2003.
3. Brunswig, R., Butler, W., Diggs, D. Wildland Fire Cultural Resources Management Plan for Rocky Mountain National Park. Center for Engaged Research and Civic Action, University of Northern Colorado, 2010 p.1-40.
4. Ehle, Donna, and William L. Baker, Disturbance and stand dynamics in ponderosa pine forests in Rocky Mountain National Park, USA. Ecological Monographs, 73(4), 2003, pp. 543–566.
5. NPS.gov, History and Culture/Collections/Archeological Sites. Last modified July 25, 2006, http://www.nps.gov/romo/historyculture/ archeology.htm.
6. Ryan, Kevin. Evaluating fire effects on cultural resources. Paper presented at cultural resources protection and fire management planning training course, western archeological and conservation center, Tucson. Sponsored by Stephen T. Mather Training Center, Harpers Ferry, West Virginia, 2001.
7. Ryan, Kevin, and A. Trinkle Jones, editors. RMRS-GTR-42, vol. 3: Wildland fire in ecosystems: effects of fire on cultural resources and archeology. Rainbow Series, Rocky Mountain Research Station, USDA Forest Service. In press.
8. Saunders, S. and Easley, T. Losing Ground: Western National Parks Threatened by Climate Disruption, Rocky Mountain Climate Organization, Natural Resources Defense Council (2006): 1-39.
9. Veech, A. Documenting Aboriginal Wood Structures at High Risk from Increased Wildfires due to Climate Change. Rocky Mountain Cooperative Ecosystems Unit, 2010