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.
Battlefields represent an important interface between nature and culture in cultural landscapes. At Gettysburg National Military Park, preserving historic landscape features associated with historic events is a constant challenge in a dynamically changing landscape. Gettysburg has over 2000 outdoor monuments and tablets, 400 of which are artillery pieces, and all of which are vulnerable to constant weathering and erosion as a result of being on display outside, exposed to the elements (Kristen McMasters 2011, personal communication). The historic patterns of vegetation are also an integral part of the historic landscape at Gettysburg. Tree lines, orchards, farm fields, and other significant areas of open and closed vegetation influenced the course of the watershed battle of the Civil War (NPS.gov 2006). Maintaining historic vegetation patterns at Gettysburg allows visitors to more accurately understand the obstacles faced by soldiers and command decisions made by both Union and Confederate armies. In fact, the primary reason that Congress created the park in 1895 was to “preserve the topographic, landscape, and cultural features that were significant to the outcome of the Battle of Gettysburg” (NPS.gov 2006).
However, climate change may present unprecedented challenges and opportunities to maintaining the historic landscapes and structures of Gettysburg. The Eastern Woodlands bioregion is expected to experience higher maximum temperatures and drier conditions, more extreme precipitation and flooding events, and significant shifts in vegetation ranges and distribution (Schramm and Loehman 2010). Such changes in temperature and moisture regimes accelerate decomposition rates, and are likely to compound the current weathering effects on monuments and structures within the park, such as rotting or cracking wooden fences, and rusting iron cannons and artifacts. Longer summers may lengthen the tourist season, putting more pressure on the park’s already burdened carrying capacity. Warmer conditions may also expand the northern range of termites, posing a very significant threat to the many wooden structures in the park (Lee and Chon 2011).
A warmer, drier climate is also expected to accelerate the process of vegetation change, leading to a landscape dominated by fewer temperate forest species and more mixed forest/savanna grassland species (Bachelet et al. 2001). While hardwood forests fall victim to inhospitable temperature ranges, water stress and competition from invasive species, vegetation characteristic of present day South Carolina and Georgia may emigrate north to Pennsylvania by the end of the century (USFS 2008). This shift may in fact reduce management needs to clear the battlefields of non-historic trees that encroach upon the desired openness of the cultural landscape.
Over the years, natural succession has been allowed to take over the Gettysburg battlefields, changing the appearance and ability to accurately interpret the historic landscape. For example, fields that have not been farmed for the past 70 years have become forests. Park managers must constantly remove trees that have grown up over the past 65-70 years, replant orchards, and re-establish grasslands in order to restore the 1863 vegetation characteristics that allowed for certain observation, firing, cover and concealment points crucial to the outcome of the battle. Often times in the management of a cultural landscape, it is not necessarily the type of vegetation that is critical to maintaining historic integrity, but the distribution of open and closed spaces formed by vegetation (Dolan 2011, personal communication). Therefore, under most climate change scenarios, the vegetation transition from temperate forest to a more open savannah environment may be much more conducive to the management and maintenance of the historic battlefields of Gettysburg.
Nevertheless, climate change will fundamentally alter the experience and appearance of Gettysburg National Military Park. Including climate change as part of the Gettysburg story will be essential to interpretation and appreciation of the cultural landscape, past, present, and future.
1. Bachelet, Dominique, Ronald P. Neilson, James M. Lenihan, and Raymond J. Drapek, “Climate Change Effects on Vegetation Distribution and Carbon Budget in the United States”, Ecosystems, 2001 vol. 4, p. 164-185
2. Dolan, Susan. NPS Historical Landscape Architect, personal communication regarding cultural landscape management, June 2011.
3. Lee, Sang-Hee and Tae-Soo Chon, “Effects of climate change on subterranean termites’ territory size: a simulation study”, Journal of Insect Science, vol. 11, no. 80, March 2011, p. 1-14.
4. McMasters, Kristen. NPS Archeologist with the American Battlefield Protection Program, personal communication regarding threatened cultural resources at Gettysburg National Military Park, July 2011.
5. NPS Gettysburg National Military Park, Park News, Goals of Battlefield Rehabilitation, last modified August 10, 2006, http://www.nps.gov/gett/parknews/gett-rehab-goals.htm.
6. Schramm, Amanda and Rachel Loehman, 2010. Understanding the science of climate change: Talking points – impacts to Eastern Forests and Woodlands. Natural Resource Report NPS/NRPC/NRR—2010/224. National Park Service, Fort Collins, Colorado.
7. United States Forest Service (USFS), Mapped Atmosphere-Plant-Soil System Study (MAPSS), Simulated U.S. Vegetation Distribution, last modified March 2008, http://www.fs.fed.us/pnw/mdr/mapss/about/modeloutput/sim_usvegdist.shtml