Conservation at the Convergence of Sun, Earth, and History

It’s not uncommon for Penn students to travel south, or west, with the onset of Spring. For a recent PennDesign studio offered with the School of Arts and Sciences, students and postgrads from the Graduate Program in Historic Preservation and the Department of Anthropology trekked to New Mexico—not to soak up the warm climate, but to analyze and combat it. These heritage conservationists, under the guidance of Professor of Architecture Frank G. Matero and Lecturer and research specialist John Hinchman, are part of a project team from the School’s Architectural Conservation Laboratory (ACL) that is assessing the climate vulnerability of earthen architecture in the arid west. Accompanying them in the field was Clark Erickson, Professor of Anthropology. 

The ACL project is focused on the Fort Union National Monument, which is the largest adobe ruin in North America and was once the largest United States military reservation in the Southwest. The site was established in 1851 to garrison soldiers and protect goods moving west; it also served as a depot for military supplies on the Santa Fe Trail. Constructed in three phases (1851, 1861, and 1863-68), the fort was the largest military complex of its time located west of the Mississippi River, and it helped assert the country’s military dominance in the southwest. After 40 years of military service, the fort was abandoned in 1891, when the railroad supplanted the Santa Fe Trail as the primary mode of transport for goods and people in the region.

The site was designated a National Monument in 1954, and in 1956, archeologists began to excavate, stabilize, and preserve the architectural ruins of the former fort. Since that time, National Park Service (NPS) officials have created various management and maintenance plans to conserve the site, which has faced increasing cycles of extreme weather. The fort’s earthen materials, including its adobe, brick, and stone walls, are a challenge to preserve in such an exposed and arid climate. As faculty research associate Evan Oskierko-Jeznacki explains, “Adobe is an extremely climate-sensitive construction material. Functionally, it acts as a ‘canary in the coalmine.’” For this reason, the fort has been a testing ground for materials conservationists since their earliest excavation in the 1950s, and Oskierko-Jeznacki was particularly eager to study its implications for the larger fight against climate change.

The current ACL project revisits prior work conducted by Penn students and faculty in the 1990s, broadening the scope of the investigation to analyze and address the site’s underlying climatic issues. In partnership with the NPS Southwest Regional Office, and funded in part by the NPS Vanishing Treasures program, the project team has already conducted an initial inventory and assessment of past site records, including historical photography, construction documents, geotechnical and engineering analyses, and weather data—all to assess the pace, causes, and methods of the site’s deterioration. The project balances the study of natural conservation and cultural conservation—an intersection of issues that drew research associate Shuang Wu (MHSPV’16) to the team. “Climate change may have been well studied by natural scientists,” she says. “But I hadn’t thought of its impact on cultural heritage before. [This project] opened a new lens for me.”

Today, with Phase II underway, the project team is taking that research back into the field. For the next two years, Matero, Hinchman, and several students and postgrads will be quantitatively measuring the current condition and deterioration of adobe walls and stone foundations using the latest conservation technology, including photogrammetry, infrared thermography, and unmanned aerial vehicles (UAVs). The resulting data, they hope, will not only inform the preservation of Fort Union, but also serve as a conservation model for significant adobe ruins throughout the Southwest.

The ACL’s work at Fort Union also presents a paradox. As second-year Historic Preservation student Silvia Callegari says, “We can preserve adobe as a ruin, [or allow it to] naturally return to the earth from which it was molded in the first place.”