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.