We examined the relationships between hemlock distribution and abundance and terrain attributes for the Coweeta Basin in the southern Appalachian Mountains. Field measurements were combined with GIS mapping methods to develop predictive models of abundance and distribution of Tsuga canadensis (L.) Carrière (eastern hemlock) and evaluate the co-occurrence of Rhododendron maximum L. (rosebay) and Kalmia latifolia L. (mountain laurel). Terrain variables were derived from USGS DEM 30-meter digital maps. Elevation, slope, aspect, terrain shape index, landform, and distance from stream were calculated from field measurements and the digital data. Terrain attributes such as elevation (r²  =  0.97, p < 0.0001), distance to stream (r²  =  0.94, p < 0.0001), and terrain shape index (r²  =  0.61, p  =  0.0015) were good predictors of T. canadensis abundance. Terrain shape index explained 56% of the variation in R. maximum percent aerial cover (r²  =  0.56, p  =  0.005). In the Coweeta Basin, T. canadensis was distributed as few, large trees mostly concentrated in near-stream locations, and it was closely associated with R. maximum. Tsuga canadensis mortality due to Adelges tsugae Annand (hemlock wooly adelgid) will result in a minor decrease in basin-wide basal area, but will substantially reduce near-stream basal area, and will also remove the largest trees in near-stream environments. In similar landscapes across the southern Appalachians, where T. canadensis co-occurs with R. maximum, riparian shading will likely remain unchanged.

The spring seed bank in a red maple bottomland swamp along the Chadakoin River in western New York was examined. Soil samples were collected at 13 microtopographically defined microsites and placed in a greenhouse for a seed bank emergence study. Mean emergent seed density was 1,037/m² with a total of 2,179 seedlings emerging. A total of 81 species were identified, 18 of which were non-native. Seed bank composition was dominated by the forbs Boehmeria cylindrica, Lysimachia nummularia, and Scutellaria lateriflora. Of the seed bank species 23% were woody trees, shrubs and vines, 46% were perennial forbs, 16% were perennial graminoids, and 15% were annuals and biennials. Microsites varied in seed bank density with elevated moss, swale, mossy stump, mossy tree hummock and mossy root containing 58.3% of the emergent seedlings. Detrended Correspondence Analysis showed that berm and stump microsites differed in seed bank composition from the other microsites which were very similar to each other. The extant swamp vegetation, with 68 species in nineteen 100 m² plots had 39 species in common with the seed bank. Seeds of the dominant woody species (Acer ×freemanii, Fraxinus pennsylvanica and Ulmus americana) were present in the seed bank. The Sorenson-Dice index of similarity between the species composition of the standing vegetation and the soil seed bank based on presence/absence data was 0.347. This moderate level of similarity indicates that Bonita swamp is a mid-successional forested wetland.

William Cameron Park is a 166 ha civic park located at the confluence of the Brazos and Bosque Rivers in Waco, Texas. During the pre-settlement period (first contact—1849), an oak-red cedar forest flourished on the ridge-top. In the early settlement phase (1849–1910), villagers cleared much of the ridge-top for logging and later for grazing. During the late settlement period (1910–present-day), vegetative cover increased markedly after the dedication of Cameron Park released ridge-top pastures. This release event resulted in delayed and differential regeneration of forest cover, first in Juniperus spp. and then in broadleaved species. Regeneration of deciduous species not only occurred after that of Juniperus spp. but initially followed historic fence-lines. Broadleaf species moved into the interiors of former pastures only within the last few decades, first in species such as Ulmus crassifolia and Quercus sinuata and later in Fraxinus texensis. The oldest ridge-top trees were Quercus fusiformis, whose size and canopy shape indicated that early settlers frequently left them to act as shade trees within pastures. Though invasion by exotic species is a management concern, historic sources reported that exotic plants, such as Ligustrum spp. were uncommon in the early 20th century. Current successional trends indicate that invasive species and anthropogenic pressures will prevent the forest's vegetation from returning to a historic species distribution.

Miscanthus sinensis, a C₄ grass, is an emerging invasive species in open and edge habitats throughout the eastern United States. To assess its ability to invade forest understories, we examined photosynthetic responses of Miscanthus sinensis grown under natural light gradients (5% to 100% full sunlight). Although there was a slight reduction in reproductive output under lower light, Miscanthus sinensis was able to maintain high rates of photosynthesis and positive carbon gain along the entire light gradient. Positive carbon gain at low light was likely due to an increased quantum yield. Photosynthetic induction for all plants was rapid, while stomatal opening during induction was slower. Rates of induction loss were slower than induction gain, and were slower than another major C₄ invasive exotic grass, Microstegium vimineum that is shade tolerant. During transient high light events, the combination of rapid induction, maintenance of induction state between sunflecks, and high photosynthetic rates, may allow for greater carbon gain than native understory plants. Miscanthus sinensis possesses some characteristics that allow it to persist in forest understories and to rapidly utilize increases in light availability, rendering it a potentially important invader of southeastern United States forest understories.

Temperature drives ecosystem function and can be estimated from potential solar irradiation (the surface angle of the Earth in relationship to the sun). However, indirect topographical proxies (i.e., aspect) are often used in lieu of direct temperature estimates; and temperature models based on potential solar irradiation typically omit elevation, a key parameter in temperature estimation. Using temperature data (2002–04) from regional weather stations and field sites in the southern Appalachian region of North Carolina and north Georgia, I test the efficacy of temperature estimations based on potential solar irradiation and present a simple method to improve such estimations by incorporating elevational temperature gradients. The heat load index, which weighs afternoon sun as more integral to heat generation than morning sun, fits actual weather station and field site temperatures better than solar angle alone. However, in all years and data sets, adjusting the heat load index for elevational substantially improves its fit with actual temperatures. Further, by calibrating the adjusted heat load estimation with annual weather station temperature data, actual field site temperature for individual years can be accurately predicted. This paper presents a relatively simple method for generating temperature data that requires only spreadsheet or statistical software. This is useful for estimating temperatures from data sets where only topographical or GPS data were collected. It also can be used to derive missing data when sampling sites outnumber temperature loggers.

Blackland prairies are a globally imperiled, rare plant community only recently discovered in central Georgia. A floristic inventory was conducted on six remnant blackland prairie sites within Oaky Woods Wildlife Management Area, 12 km southeast of Warner Robins. The 43 ha site complex yielded 351 species in 219 genera and 89 families. Four species new to Georgia were documented. According to several state and federal rankings, twenty-three rare plant species occur within the study area; these include one federally endangered species (Silene catesbaei) and one candidate for federal listing (Symphyotrichum georgianum). Twelve plant communities are described. The inventory supported the designation of a new ecological association, the Georgia Eocene chalk prairie. Maps of the study area and photographs of the prairies and rare plants are provided.

The vascular flora of the North Chickamauga Creek Gorge State Natural Area (NCCG) was studied during three growing seasons from 2006 to 2008. NCCG is located in Hamilton and Sequatchie Counties, Tennessee, on the eastern edge of the Cumberland Plateau. Within the study area are 2,862 ha of eastern deciduous forest that contains 12 distinct habitat types. A survey of these habitat types yielded 110 families, 329 genera, and 604 species or lesser taxa, including 238 county records. Seventy-six introduced species were found, comprising 13% of the total flora. Eleven species with either a state or federal listing were documented: Castanea dentata, Diervilla lonicera, Diervilla rivularis, Glyceria acutifolia, Nestronia umbellula, Spiraea virginiana, Scutellaria montana, Sabatia capitata, Woodwardia virginica, Panax quinquefolium, and Viola tripartita. A species-area curve for the Cumberland Plateau of Tennessee was constructed from the current study and seven other similar studies of the plateau. Three family level species-area linear regression lines were also constructed, demonstrating that the natural area reaches or exceeds expectations for Asteraceae, Poaceae, and Cyperaceae.

Although the Appalachian Mountains of southwestern Virginia, United States, are known to represent a major ‘hotspot’ of biodiversity for North America, no significant survey of overall lichen diversity has been conducted in the region thus far. Presented here is a list of 221 distinct taxa of lichens, lichenicolous fungi, and ‘lichen allies’ collected during the 2008 Hugo L. Blomquist Bryological and Lichenological Foray in the mountains of southwestern Virginia. Collections were made from diverse habitats, primarily in the Mount Rogers National Recreation Area (MRNRA), and yielded 41 potential state records. Particularly noteworthy collections include: Sphaerellothecium coniodes (a lichenicolous fungus that was not previously known to exist in North America), Hypotrachyna lividescens (a primarily neotropical macrolichen that has not previously been reported from North America), Pycnora praestabilis (a lignicolous crust not previously reported from any other location in eastern North America), Heterodermia erecta (a foliose lichen previously known in the world only from a single small region of Georgia/North Carolina), and Psilolechia clavulifera (a crustose lichen taxon previously reported from only one other location in eastern North America). The sheer diversity of lichens, along with the number of rare and/or potentially endangered taxa, highlights the need for continued preservation efforts in MRNRA and the southern Appalachian Mountains in general.

Woody grapevines (Vitis spp.) are common in the deciduous forests of the southeastern United States. Their growth habit makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Leaf morphology is the most readily available character used for species identification. However, most mature grapevines do not produce leaves below the upper canopy and if they do, these leaves are morphologically indistinguishable from other species. In order to sample leaves from mature grapevines, the doubled rope climbing method was used to access the canopy in Great Smoky Mountains National Park in Tennessee, Daniel Boone National Forest and Berea College Forest in Kentucky, and Ha Ha Tonka State Park in Missouri. Leaf voucher specimens were collected from the upper canopy and used to create a modified key to species for those regions. The purposes of this paper are to report a new method for collecting grapevine leaf vouchers from the upper canopy of trees, to present a modified key used for identifying dried leaf vouchers of Vitis species, and to present a discussion of the possible utility of this research for future studies.