As interest in invasive species management increases, new information with respect to invasive species abundance and distribution in invaded habitats is imperative. One essential type of information is demographic data. When invasive plants colonize a new habitat, their numbers may be low at first, but the population may undergo rapid expansion. We were interested in the effect of intraspecific density on the population dynamics and life history attributes of Alliaria petiolata a Eurasian biennial herb that has become an invasive pest in portions of North America. Thirty plots were established in a mesic second-growth deciduous forest in high, medium and low density patches of A. petiolata rosettes. Demographic data were collected for all A. petiolata cohorts present in the plots from 1996–1998. In June 1998 all first year rosette and second year mature individuals were harvested, dried and weighed. Stage-based population projection matrices were constructed in order to compare demography among p...

To better understand the response of eastern deciduous forest herbs to microenvironmental changes associated with logging, the effects of experimental light and soil compaction treatments were examined in six herbaceous plant species characteristic of varying successional stages. We found severe growth reductions and increased mortality of Osmorhiza claytonii (Michx.) C.B. Clarke, a shade-tolerant forest perennial, when grown in full sun and greater soil compaction. Deeply shaded conditions, similar to those beneath regenerating forests, resulted in reduced growth of early successional species such as Galium aparine L., and Eupatorium rugosum Houtt. Growth of other species such as Geum canadense Jacq., and Elymus hystrix L. appeared to increase in the patchy, intermediate light treatment mimicking mature eastern deciduous forests. Soil compaction caused severe reductions in height and biomass of Eupatorium rugosum and O. claytonii, early- and late-successional species, respectively. While harvested stands experience relatively uniform light environments, canopy gaps and sunflecks in mature eastern deciduous forests create heterogeneous light environments often correlated with recruitment, growth, and diversity of understory herbs. Therefore, management approaches that minimize alteration of forest environments and mimic natural disturbance patterns may be important to the maintenance and regeneration of forest herbs.

Silvicultural treatments alter fuel dynamics in forested systems, which may alter fire regime. Effects of thinning and prescribed fire on forest-floor fuels were studied in mixed-oak forests of south-eastern Ohio to examine fuel dynamics over time. Fuel characteristics were measured before, immediately after, and 3 years following fire and thinning treatments along 20-m transects (n = 432) following Brown’s planar intersect method. Measurements were taken to determine litter, duff, 1-h, 10-h, 100-h, and 1000-h sound (1000S) or rotten (1000R) fuel mass. Coarse woody debris (CWD) was sampled on 432 additional 80-m2 belt-transects. Repeated-measures analysis of variance with post-hoc Bonferonni comparisons was used to analyse the change in the fuels over time. The specific effects of silvicultural treatments varied over time with changes in larger, sound fuels (1000S and CWD) persisting longer than changes to finer (litter, duff, 1-h, 10-h, and 100-h) or less-sound (1000R) fuels, which appear to be more transient. Unlike in western North America where fuels accumulate over time, decomposition and productivity appear comparable in eastern mixed-oak forests. Aside from their impact on decomposition or productivity rates, silvicultural treatments appear to have little impact on fine-fuel loading in these systems.