Fires and drought during the Euro-American settlement period (1850-1950) in the Nebraska Sand Hills

The connections among human activity, fire, and drought are examined in this study of historic records and sediment cores collected from six lakes within the Nebraska Sand Hills. We use microscopic charcoal particles from lake sediment cores to reconstruct fire history from ~1800 to 1950 C.E. We also use historical documents and the dates of post office establishment to constrain Euro-American settlement patterns in the regions adjacent to the cored lakes and compare the fire histories with the historic record of regional droughts to understand the connections between environmental conditions and land-use change associated with Euro-American settlement. Fires in the Great Plains are commonly assumed to be controlled by fuel availability, and in many studies periods of higher biomass burning are attributed to greater fuel loads. While both periods of drought resulted in decreases in biomass burning, the early 20th century drought (Dust Bowl) resulted in the lowest levels of burning during our period of inquiry. However, in one site, we found that increases in biomass burning occurred during periods of late 19th and early 20th century droughts, and we attribute these anomalies to increased anthropogenic ignitions or a localized increase in fuel loads. Above average biomass burning is recorded at all but one of our study sites during the initial phases (ca. 1850–1875 C.E.) of Euro-American settlement. Afterward, the six sites become much more varied and regional trends are less coherent, most likely because of the low population density and temporal scale of inquiry.