Sassafras trees are unusual among trees because they have three distinctive leaf shapes. As seen in the photo (right), these shapes are 1) a simple, unlobed leaf, 2) an asymmetrical leaf resembling a mitten, and 3) a three-lobed leaf. Bark of young trees is smooth and green, while older trees have reddish, furrowed bark. Bruised sassafras leaves have a spicy aroma, reminiscent of root beer.
Sassafras plants are abundant in much of Shenandoah National Park, particularly on rocks of granitic composition (for example, on Old Rag in the Central District) as well as on metasedimentary rocks (for example, on Rocky Mount in the South District). Sassafras trees are intolerant of shade (USDA PLANTS database), and the distribution of larger sassafras trees (those with trunks that are at least several inches in diameter) tends to reflect the high-light requirements of this species. For example, sassafras trees can often be found in rocky habitats that are marginal for other species.
In many parts of the park, sassafras seedlings, less than knee high, are abundant on the forest floor, but these seedlings are unlikely to mature under the shade of a dense canopy. However, when a gap opens in the forest canopy, allowing more light to the forest floor, an opportunity arises for small sassafras seedlings to grow into mature trees. Sassafras trees grow rapidly in forest gaps. Elsewhere in
Virginia , growth rates of sassafras saplings have been measured to be nearly a meter in height during a single year, when light conditions were favorable in forest gaps (Orwig, 1995). These growth rates of sassafras are rapid relative to a number of other common Virginia trees (Orwig, 1995). Thus, sassafras trees take advantage of gap formation to grow rapidly into a mature tree, before eventually being shaded out by slower-growing, but taller and generally longer-lived canopy species such as oak (Qurecus spp.) or tulip poplar (Liriodendron tulipifera).
Sassafras is a fire-adapted species that prospers in areas of the park that have burned in the recent past. This characteristic goes hand in hand with the light requirements of the species, because fire often kills large, weak trees, creating gaps in the canopy and enhancing opportunities for sassafras to grow and mature.
Various parts of the sassafras plant have been used medicinally by Native Americans (USDA PLANTS Database). In addition, sassafras root was once used as one of the flavorings in root beer (Sweeney, 2005). The compound that gives sassafras the distinctive flavor and odor is safrole. Because safrole has been identified as a carcinogen, the Food and Drug Administration now prohibits its use in food (FDA, accessed July 2005).
References and Links:
Orwig, D.A., and Abrams, M.D., 1995, Dendroecological and ecophysiological analysis of gap environments in mixed-oak understoreys of northern
Virginia , Functional Ecology, v. 9, p. 799-806.
Petrides, George A., and Wehr, Janet, 1998, A Field Guide to Eastern Trees: Houghton Mifflin Company,