Volume 76 - Issue 2 (June 2011)

ABSTRACT The factors affecting tree mortality have a significant impact on forest dynamics. Trees experience numerous biotic and abiotic stresses, and allocation of available resources can determine tree survival in different conditions. Recent studies support an intraspecific relationship between radial growth rate and longevity. This study investigates the existence of such a relationship in the American chestnut [Castanea dentata (Marsh.) Borkh.] across a landscape in southwestern Virginia. Growth rate and age at death were measured on basal cross sections of recently dead American chestnuts. The relationships between growth rate and age at death and between growth rate and chestnut blight presence were analyzed. Average growth rate during the first 10 years of growth and age at death were correlated; chestnuts with fast early growth died younger than chestnuts with slow early growth. Additionally, we found that the average growth rate during the last 10 years of growth was a significant predictor of blight infection at death. Our results provide further support for a link between radial growth rates and longevity within species. Our results also support previous findings that relate radial growth rates to blight susceptibility, possibly due to tradeoffs in resource allocation to growth versus defense. This study emphasizes the impact of life history on mortality in a tree hosting a pathogen and could inform forest management practices for chestnut conservation in the face of potential mortality from blight infection.

ABSTRACT The College Woods in Williamsburg, Virginia (a.k.a. Matoaka Woods) contains a maturing post-cultivation upland hardwood forest (oaks, beech, tuliptree, hickories). In 1994 four size classes of woody stems were sampled on 27 permanent plots, and those same plots were re-sampled in 2003. Cluster analysis revealed that between samplings there was little change in the composition of the large tree ($10 cm dbh) or small tree (2.5–10 cm dbh) size classes. There was great change in the density of certain species in the sapling (1.4 m tall, ,2.5 cm dbh) and tall seedling (0.5–1.4 m tall) size classes, even though the sapling size class was initially similar to the small tree layer. In these two smaller size classes, change was mostly great decrease in some species (Viburnum acerifolium, Cornus florida, Acer rubrum, and Euonymus americana) rather than increase in the remaining abundant taxa (Fagus grandifolia, Ilex opaca, Gaylussacia spp. and Vaccinium spp.). Preferential browsing by an increasing deer population likely caused these dramatic changes.

ABSTRACT Over the past several centuries, upland successional grasslands of Virginia have been invaded by exotic grasses introduced from Europe. We examined three strategies (vegetation removal, nitrogen manipulation, and seeding) for improving the establishment of the native grasses Andropogon gerardii, Sorghastrum nutans, and Schizachyrium scoparium to the northern Shendandoah Valley in Virginia. Experimental plots were subjected to one of four vegetation removal techniques: plowing, glyphosate herbicide, glyphosate plus imazapic herbicide, or no removal. Each plot was divided into two subplots that were either seeded with native grass seeds or not. Within all subplots three levels of soil nitrogen were established (low, ambient, high). The result show that plots subjected to vegetation removal using both herbicides and a reduction in the plant-available soil nitrogen yielded the highest number of native grass seedlings. Native grasses were observed in all plots except for the control which had no vegetation removed. The results from this study inform grassland managers of the importance of vegetation removal prior to restoration attempts.

ABSTRACT This study investigated several ecological parameters for populations of Obolaria virginica in southeast Missouri where it is listed as endangered. Investigations during the 2006 and 2007 growing seasons included population size estimates and dispersal patterns. A secondary investigation during the 2007 season quantitatively assessed the impact of leaf litter on O. virginica flower production. Obolaria virginica reflected the pattern of a spring ephemeral with emergence as early as mid-February and senescence by early June. Plants grew to an average of 9.2 cm in height and had 14 flowers per individual in each season. Population size estimates ranged from 833–7,820 individuals, with a distinctly clumped distribution pattern. Leaf litter depth appears to negatively affect emergence and flower production in this perennial forest herb.

ABSTRACT Results of pollen analyses of dual sediment cores from alluvium of Caddo Creek in northern Anderson County in East Texas replicate trends of vegetation change during the last 6,700 years. These floral changes include most importantly a long-term decline of hickory and a rise of pine due to physiographic factors of irreversible soil acidification. With a view to factors of climate change, a major xeric phase is defined between 4000 and 3000 BP, when grassland vegetation expands beyond its present range. Human impacts during the prehistoric period are comparatively limited despite a regional presence of many archaeological sites, although tentative evidence for a Native sylviculture of hickory is considered. Methods of alluvial palynology pioneered in East Texas are validated through an application of strict checks on palynological data sets.

ABSTRACT Carex molestiformis, described in 1997 as an endemic to the Ozark and Ouachita Mountain regions, is newly collected from Georgia, Mississippi, and Ohio. Herbarium records also have confirmed this species from North Carolina, Virginia, and West Virginia bringing the overall range of this species to 11 states. A morphological comparison of C. molestiformis from east of the Mississippi River with western populations did not reveal regional differences. Some eastern populations occupied ruderal habitat, namely drier grassy roadsides and hay meadows rather than the river bottom openings typical of western populations. New chromosome counts for this species from the eastern portion of its range confirmed existing reports of n 5 37 and also found agmatoploidy with n 5 35.

ABSTRACT Cumberland Island National Seashore, Camden County, Georgia, is administered by the National Park Service, United States Department of the Interior, and includes over 85% of the terrestrial acreage (7,880 ha; 19,472 acres) comprising Cumberland Island. A series of collecting trips over one year (2006–07) yielded 24 species of native angiosperm species not previously vouchered for the Island, presented here in an annotated list. These specimens also verify the presence of nine species vouchered several decades ago but not confirmed by a recent comprehensive inventory. Five species of these latest collections are state-ranked as species of special concern in Georgia. With the addition of these new records, the total now is 531 vouchered vascular plant species for this national park.

Clinopodium gracile (Benth.) Kuntze (LAMIACEAE)—Cobb County: Marietta, Chattahoochee River National Recreation Area, Cochran Shoals–Interstate Parkway/ Gunby Creek unit Significance. The first vouchered record for Georgia was discovered during a floristic inventory of the Chattahoochee River National Recreation Area for the National Park Service (Zomlefer et al. 2011).

Lotus tenuis Waldst. & Kit. ex Willd. (FABACEAE)—Kenton County: Marydale. Located along US I-75/71 N, at the jct. with US I-275, ca. 9.5 km from the Ohio border. Growing in a disturbed weedy wet meadow with inundated depressions on the northbound interstate right shoulder. Associates: Bromus commutatus Schrad., Cirsium arvense (L.) Scop., Hordeum jubatum L., Juncus articulatus L., Puccinellia distans (Jacq.) Parl., and Schedonorus arundinaceus (Schreb.) Dumort.; 39u2590.20N, 84u6936.700W; 5 June 2007, R.L. Thompson and D.B. Poindexter 07-187 (BEREA, BOON).

Significance. This plant was casually mentioned as occurring in Breathitt County, Kentucky, in a surface-mined area by Campbell and Medley (2009), but was not recorded as definitively established in their atlas, nor is it attributed to the Commonwealth by Isley (1990), Jones (2005), Kartesz (2010), Medley (1993), or the PLANTS Database (United States Department of Agriculture, Natural Resources Conservation Service [USDA, NRCS] 2010).

Torilis japonica (Houtt.) DC. (APIACEAE)— Watauga County: Boone Greenway Trail, 36.207732uN, 281.65300uW, 954 meters elevation, small population growing at edge of paved trail with Pinus strobus L., Cornus florida L., Prunus serotina Ehrh., Ranunculus repens L., Daucus carota L. and Toxicodendron radicans (L.) Kuntze, 13 July 2009, M.W. Denslow, M.L. Denslow and G.L. Katz 2609 (BOON, duplicate to be distributed); Boone, along Faculty Street, 36.205949uN, 281.671988uW, 961 meters elevation, common along roadside bank with Pinus strobus, Acer rubrum L., Toxicodendron radicans, Rubus occidentalis L., Celastrus orbiculatus Thunb., Oenothera tetragona Roth, Impatiens capensis Meerb., Daucus carota, Eurybia divaricata (L.) Nesom, 9 August 2009, M.W. Denslow 2613 (BOON, duplicates to be distributed); ASU [Appalachian State University] Environmental Studies Area, 25 July 1999, M. Moore 39 (BOON).

Significance. These collections are the first records of this taxon from North Carolina. Torilis japonica is native to Europe and Asia where it occurs in a variety of habitats including disturbed areas (Flora of China Editorial Committee 2006). This taxon has been widely introduced into the northern United States and Canada, but appears less common in the southern United States (Ball in press).