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.

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.

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.

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.

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.

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  =  37 and also found agmatoploidy with n  =  35.

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.

A good working knowledge of seed germination requirements is important for plant establishment for restoration and experimentation, particularly in wild plant species. Some seeds require a period of after-ripening and cold stratification before germination will occur. In this study we examined the effects of after-ripening and stratification time on seeds from three disjunct populations of Arabidopsis lyrata ssp. lyrata, from serpentine and limestone sand substrates of the Mid-Atlantic region of the United States. Differences among populations were evaluated through seed germination percentage and rate. Overall germination percentage and rate significantly varied by population, with seeds from the two serpentine populations having a lower germination percentage and rate than seeds from the limestone sand population. After-ripening time also significantly affected germination percentage and rate, with both measurements generally being the highest in 4 and 8 month-old seeds. Stratification did not generally alter germination percentage compared to the untreated control. However, stratification appeared to have the greatest effect on the germination rate of seeds that had after-ripened for 4 months, but the number of days of stratification required was not consistent across populations or across years. The variation observed among the populations of A. lyrata ssp. lyrata tested is a starting point for understanding how these differences developed and how they contribute to the success of each population in its native environment.

Phylogenetic studies in the eastern United States have uncovered patterns of genetic variation that suggest an influence of glacial history on various plant species. Similarly, studies have indicated regional-level genetic discontinuities corresponding with reduced gene flow between regions and populations, often associated with a geographical barrier. Here we examine the population genetics of a species found mostly in northeastern North America, but with populations at high elevations along the southern half of the Appalachian Mountains. Nine populations of the plant species Sibbaldiopsis tridentata (Rosaceae) in the eastern United States were sampled, using amplified fragment length polymorphism (AFLP) molecular markers. Levels of genetic diversity within and among populations were determined. Results indicate that the degree of intrapopulation genetic variation varies between populations. A statistically significant discontinuity is identified between populations east and west of the Valley and Ridge Province, which suggests that this region has likely acted as a barrier to historical gene flow. Within the Appalachian Mountains, northeastern populations show varying levels of genetic similarity to southeastern populations with no clear genetic signal delineating northern and southern populations. The genetic patterns discerned in this study suggest a complex species history, which should provide insight in future studies of this and other ecologically similar plant species.

There has been question whether the taxon known as Yucca filamentosa (Agavaceae) is to be distinguished from the taxon known as Yucca flaccida. Much of the uncertainty lay in the absence of sure knowledge of the forms intended by their original authors. A neotype of Y. flaccida from Florida was selected in 2006. Here, the type locality in Virginia of Y. filamentosa is revisited and an epitype is selected. The two taxa, as represented by plants from these two type localities, differ markedly in a number of characteristics. It is suggested that Y. filamentosa and Y. flaccida be retained at specific rank.