Little Bighorn Battlefield National Monument Riparian Forest Demography: Hydroclimatic Tree-establishment Conditions And A Search For “Witness” Trees
Pederson GT, Gray ST, Lesser M, Allen L. 2012. Little Bighorn Battlefield National Monument Riparian Forest Demography: Hydroclimatic Tree-establishment Conditions And A Search For “Witness” Trees. USGS and University of Wyoming. U.S. Geological Survey, Northern Rocky Mountain Science Center, 2327 University Way (Suite 2), Bozeman, MT, 59715
A dendroecological analysis of riparian area cottonwoods (Populus deltoides) along the Little Bighorn River at the Little Bighorn Battlefield National Monument (LIBI) in southeastern Montana was conducted to (1) describe the age structure of the gallery forests, targeting in particular trees that may have been alive during the battle in 1876; (2) identify potential hydroclimatic factors (e.g. floods, drought) that may have influenced establishment and development of the stands; and (3) indentify cottonwoods and other trees with potentially dateable fire scars. Of particular interest for this study was the sampling of a lone cottonwood at Medicine Tail Coulee since it may be the same tree documented on the 1876 Kill Eagle map demarcating the point where the Cheyenne drove Custer back. Although there were no riparian area trees definitively dated back to the year of the battle, uncertainty related to tree age at coring height suggests a good number of trees were probably seedlings or saplings. The lone cottonwood “witness” tree, was at least 25-years old at the time of the battle in 1876, and is likely the tree documented in the Kill Eagle map – assuming a death date of 1970. No fire scars were found within the riparian area forests, suggesting fires on surrounding grasslands didn’t burn through the riparian area; haven’t burned through the riparian area since before the 1880s, or; burn at such a low intensity they fail to scar the trees. The current stands can be grouped into two cohorts, with a major establishment pulse c. 1880-1900, with minimal recruitment occurring c. 1900-1925. With the exception of a single tree establishing in 1961, we found no evidence of cottonwood establishment since the 1930s even though floods of sufficient magnitude to expose new sediment have occurred. The temporal and spatial pattern of cottonwood demography is consistent with the flood-driven model of cottonwood establishment in the western U.S. The lack of substantial cottonwood establishment in the riparian area since the 1930s is similar to results reported in other studies and may arise from either natural demographic fluctuations or land-use changes.
- Type
- Unpublished Report
- Authors
- Pederson, Gregory; Gray, Stephen; Lesser, Mark; Allen, Leslie
- Date of Issue
- 2012-10-23
- Publisher
- USGS and University of Wyoming
- Units
- LIBI
- Keywords
- Crow Agency, Custer Battlefield, Little Bighorn Battlefield, Little Bighorn Battlefield NM, Little Bighorn Battleflield National Monument, Little Bighorn River, Montana
- Subjects
- Ecological Framework: Water | Hydrology | Surface Water Dynamics