Michaux's sumac (Rhus michauxii Sargent) is a federally endangered species native to the lower piedmont and upper coastal plain of the Southeastern United States. Michaux's sumac is an entomophilous, dioecious, rhizomatous shrub in the Anacardiaceae family and is a disturbance dependent species that typically occurs on right of ways and roadsides. Fort Pickett, Virginia has the largest known population in the world. The Fort Pickett population is unique because the majority of the colonies are located in habitats maintained by frequent fire caused by military training. Our objectives were to investigate the relationship between disturbance and the reproductive potential of Michaux's sumac. We collected detailed data on the density staminate, pistillate and non-flowering stems of Michaux's sumac 25 separate colonies. In addition we collected detailed floristic and structural habitat data at the same locations. The strongest correlations were between woody competition and pistillate density. In the 2-5 m strata the influence of woody density, total density, and dbh on pistillate Michaux's sumac density were significant (P < 0.05) and strongly correlated with r2 of 0.558, 0.488, and 0.511 respectively. Two multiple linear regression models showed significant (P<0.05) negative relationships between woody competition and Michaux's sumac density. Staminate density was negatively correlated (r2 =0.333) with a linear combination of dbh 2-5m and total aerial vegetative cover. Pistillate density showed a negative correlation (r2 =0.635) with a linear combination of dbh 2-5m and total aerial vegetative cover. Wildfire effectively controlled woody competition in many colonies thus increasing flowering and overall reproductive potential.
