Sedimentary charcoal is a useful fire proxy. Recent advances in the morphological and morphometric analyses of individual charcoal particles have enabled more nuanced paleofire interpretations. However, many uncertainties exist regarding the linkages of these particle characteristics with fuel type burned. Further, most of this proxy development research has been conducted in northern boreal biomes, which poses questions as to its universality. In this paper, we leverage a 300-year sediment record from a mill pond in southeastern Virginia, USA. Historical events and land-use changes are well constrained in Williamsburg, allowing us to compare our data with these known boundary conditions to (1) make inferences about the fuel sourcing of certain charcoal morphotypes, and (2) identify the potential controls of several charcoal morphometric characteristics. We found that the morphology and morphometry of particles in the Matoaka sediments changed in response to broad-scale shifts of historical land use and population. Prior to the American Revolutionary War (ca. 1780 CE), charcoal morphologies indicative of agricultural burning coincided with agricultural and local population expansion. Immediately preceding the American Civil War (1780-1865 CE), charcoal in Lake Matoaka recorded reforestation driven by depopulation and economic depression. After the fall of the Confederacy (ca. 1865 CE), changing charcoal morphologies reflected increased population and urban development. This increase became especially pronounced in the early 1900s, but lasted until the modern. Additionally, shifts of charcoal morphologies potentially reflect increased coal combustion. Comparison of these historical variations with morphotype shifts shows that Types M and S/B charcoal, types defined by their geometric shapes and exhibition of structure, are likely sourced from burning herbaceous fuels. However, we find that the variability of morphometric characteristics makes it unlikely that other morphologies are sourced from sole fuel types. Lastly, we propose three additional morphotypes, Types AI (angular and irregular shaped particles), E (irregular, complex shaped particles), and T (triangular particles), to an existing charcoal morphological key for application in the SE USA. Overall, this research underscores the need for more work calibrating paleofire methodologies in the SE USA.
