By Dr. Michael Stambaugh- University of Missouri
Webinar presented December 1, 2020
Abstract: Vegetation of the Cumberland Plateau (USA) has undergone dramatic transitions since the last glaciation and particularly since the onset of widespread logging and 20th century fire exclusion. Shortleaf pine (Pinus echinata Mill.), one of the most fire-dependent conifers in the U.S., occurs throughout the Cumberland Plateau, but its abundance has declined dramatically since Euro-American settlement and continues to decline. To better understand the historical ecology of fire within the natural range of shortleaf pine, we reconstructed fire regimes at three new sites throughout the central and southern Cumberland Plateau region based on fire scars on shortleaf pine trees. Fire event chronologies extended back to the 17th-century and revealed historical fire regimes that were frequent and dominated by dormant season and low-severity events. Fires occurred on average every 4.4 to 5.3 years at the study sites before widespread Euro-American settlement, and were more frequent (2.3 to 3.8 years) following settlement. Cumberland Plateau fires may be linked to adjacent ecoregions such as the Eastern Highland Rim to the west. Among all sites, we found long-term trends in fire activity were similar and fit into a regional waveform pattern of fire activity likely driven by humans (i.e., Native American depopulation, European settlement, and 20th century fire exclusion). In conclusion, the decline in shortleaf pine and other fire-dependent ecosystems across the Cumberland Plateau is due to multiple interacting factors and, based on these data, frequent fire should be considered a historically important ecological driver.