Volume 69 — Issue 2 (June 2004)

Ailanthus altissima (Mill.) Swingle (Simaroubaceae, tree-of-heaven) is native to northern China where it has a long history of association with human habitation and disturbance (Whitney and Adams 1980). It was introduced from China to Paris between 1740 and 1750 (Hu 1979). It was introduced into the United States on an extensive scale in 1820 (Dame and Brooks 1972) as an ornamental shade tree recognized for its rapid growth, luxuriant compound leaves, and ability to tolerate the stresses of urban areas (Hough 1960, Dirr 1983). It is now naturalized throughout the eastern United States, growing from Massachusetts and Ontario south, and also occurs to a lesser extent from the southern Rocky Mountains to California (Elias 1980).

This study evaluates and quantifies the variation in vegetation, plant nutrients, and microclimate across four topographic aspects in an Appalachian watershed (39°39’43″N, 79°45’28″W). The study found that the north and east aspects were 27-50% more productive than the west and southwest aspects. Species groups that showed strong aspect preference included yellow poplar (Liriodendron tulipifera), black cherry (Prunus serotina), chestnut oak (Quercus prinus), and white oak (Quercus alba); the former two being dominant on the north and east aspects while the latter two dominate the west and southwest aspects. Red oak (Quercus rubra) and red maple (Acer rubrum) showed mild aspect preference indicating their broad ecological amplitude. Although the north and east aspects had greater biomass, the west and southwest aspects had about 23% more stems per hectare.

There were large differences in microclimate among the four aspects. Air temperature during midday period averaged 25.2℃, 24.9℃, 30.5℃, and 29.4℃ for the north, east, west and southwest aspects respectively. The maximum temperature difference between the mesic (north and east aspects) and xeric (west and southwest aspects) sites was 5.55℃ and was observed at noon. The relative humidity at the xeric site was about 25% lower than that at the mesic site during midday periods. Plant water stress as measured by vapor pressure difference was about 37% higher on west and southwest aspects than on north and east aspects. Plant nutrients only showed minor differences with concentrations being higher on the north and east aspects except for phosphorus, which was higher on the west and southwest aspects.

A former chestnut stand on the Cumberland Plateau of Tennessee was sampled in 1952/53, 1979, and 2000. The site was clear-cut in 1921/22, and has remained unburnt and relatively undisturbed. Chestnut stumps are present, but sprouts are not. Liriodendron tulipifera remained important in the canopy since 1952/53. Acer rubrum and A. saccharum increased in the canopy, but only A. rubrum did so in the subcanopy. Quercus rubra/velutina increased in the canopy, and decreased in the subcanopy. Shade intolerant (Juglans nigra, Liquidambar styraciflua, Ulmus rubra, Fraxinus americana) and shade-tolerant (Tilia americana, Aesculus flava) species declined, perhaps due to absence of large-scale disturbance needed for regeneration. Juglans cinerea and Cornus florida were impacted by fungal pathogens. Although J. cinerea was an important replacement species, no individuals are currently present. Cornus florida is present in the canopy, but not in the subcanopy. Lindera benzoin and Viburnum acerifolium increased, apparently in response to C. florida‘s decline.

In 1794 Andre Michaux discovered dwarf sumac Rhus michauxii in Mecklenburg County, North Carolina, and in 1803 published a species description under the name Rhus pumila. In 1895 C.S. Sargent assigned the name R. michauxii to correct Michaux’s use of a homonym and to honor its discoverer. The type location is now in Union County, North Carolina, which was formed from part of Mecklenburg County in 1842.

A descriptive floristic study of the vascular flora and plant communities was conducted at the John B. Stephenson Memorial Forest State Nature Preserve in Rockcastle County, Kentucky, during the growing seasons of 1997-98. This 51-hectare rugged natural tract of the Berea College Forest, formerly known as Anglin Falls Ravine, is the 36th Kentucky State Nature Preserve. The vascular flora consists of 98 families, 310 genera, and 538 species (56 of these non-native). Species are classified into Lycopodiophyta (4), Polypodiophyta (29), Pinophyta (5), and Magnoliophyta (500). The four largest families in species are the Asteraceae (79), Poaceae (46), Cyperaceae (35), and Fabaceae (20). Eleven plant communities are described from field survey and plant sampling work. Seven are forested, two are microhabitats within those seven communities, one is a wetland meadow, and one is a culturally disturbed community. The Preserve supports an excellent example of protected Mixed Mesophytic Forest in the Northern Cumberland Plateau of Kentucky.

Noteworthy Collections: Distribution Of Aneura (Hepaticophyta) In South Carolina, Virginia, District Of Columbia, And Maryland

A survey of vascular flora was completed at wetland sites in the Tulula Creek floodplain in Graham County, North Carolina as part of a comprehensive ecological study. The vegetation survey was conducted in forested and unforested fen and floodplain wetlands in 1994 and 2001, and in a forested floodplain wetland in 2001 in order to document plant species occurring in these rare mountain habitats. A total of 107 taxa representing 52 families were identified. More than 66% of the taxa also have been reported in other non alluvial wetlands in the region; about 31% of the taxa identified in the Tulula Creek wetland complex have been reported in non-alluvial wetlands in West Virginia and about 12% have been reported in the non alluvial wetlands of northeastern United States and adjacent Canada. This paper documented the vascular plant communities within this rare wetland complex before intensive stream restoration began in 2001.