Jeff Lukas and Connie Woodhouse, assisted by Henry Adams, carried out a dendroecological study of the riparian cottonwood forest at the recently established Sand Creek Massacre National Historic Site in southeastern Colorado, under the guidance of the National Park Service, the Cheyenne and Arapaho Tribes of Oklahoma, and the Northern Arapaho Tribe. The objectives of the research were to identify trees that may have been alive at the time of the massacre (1864), describe the overall age and spatial structure of the stands, and link these patterns of tree establishment with hydrological and climatic variability over the last century and longer.
While no trees were definitively dated to 1864, the tree-ring evidence indicates that multiple trees were alive at that time, probably as seedlings or saplings, confirming the belief of tribal members that “witness trees” were still present at the site. The temporal and spatial patterns of tree establishment are consistent with the prevailing flood-driven model of cottonwood establishment in western North America; the initiation dates of the three major age classes coincide with probable flood events on Big Sandy Creek. The completed study provides the Park Service and its tribal partners with data critical to managing the cottonwood forest at Sand Creek as both a natural and cultural resource.
The study was the subject of a feature article in the Daily Camera: "Witnesses to horror: CU researchers study Sand Creek cottonwoods," by Erika Engelhaupt (April 29, 2006).