Bundle sheath extensions (BSEs) are key features of leaf structure with currently little-understood functions. To test the hypothesis that BSEs reduce the hydraulic resistance from the bundle sheath to the epidermis (r(be)) and thereby accelerate hydropassive stomatal movements, we compared stomatal responses with reduced humidity and leaf excision among 20 species with heterobaric or homobaric...

Pollination by insects in forests is an extremely important process that should be conserved. Not only do pollinating insects help to maintain a diversity of plants within forests, but they also aid in pollinating crops found near forested land. Currently, the effects of various forest management practices on floral visiting insect abundance or diversity is unknown, so we investigated how presc...

Few studies have considered how interactions between woody and herbaceous species change in direction or magnitude over time or with traits of the dominant woody species. We used a chronosequence approach to explore these interactions in a montane meadow in which Pinus contorta Dougl. ex Loud. and Abies grandis (Dougl. ex. D. Don) Lindl. have established gradually over a period of >70 years. Ef...

Micro-relief heterogeneity can lead to substantial variability in microclimate and hence niche opportunities on a small scale. We explored the relationship between plant species richness and small-scale heterogeneity of micro-relief on the subtropical island of La Palma, Canary Islands. Overall, we sampled 40 plots in laurel and pine forests at four altitudinal bands. Species richness was recor...

In the Southern Appalachian Mountains of eastern USA, pine-hardwood ecosystems have been severely impacted by the interactions of past land use, fire exclusion, drought, and southern pine beetle (SPB, Dendroctonus frontalis). We examined the effects of restoration treatments: burn only (BURN); cut + burn on dry sites (DC + B); cut + burn on sub-mesic sites (MC + B); and reference sites (REF; no...

The ecology of woodland herbaceous species is reviewed. Many factors affect woodland herbs but there have been few studies of their impacts on long-term patterns. Results from a 10-year study of two species in a deciduous forest in Maryland are presented. Populations of Cynoglossum virginianum were influenced by their proximity to tree gap disturbances. Populations of Tipularia discolor were pr...

A large — but unknown — number of alien species have become established in ecosystems across the United States, where some are causing serious damage. Forests of the Northeast have been particularly impacted by exotic species ranging from insects to starlings, and from herbaceous plants to pathogens. Government trade policies exacerbate the threat of new introductions. Funding shortfalls hamper...

Significant night-time stomatal conductance and transpiration were found for 11 out of 17 species with a range of life histories (herbaceous annual, perennial grass, shrub, tree), photosynthetic pathways (C(3), C(4)), and habitats in the western United States. Across species and habitats, higher night-time conductance and transpiration were associated with higher daytime values. The prevalence,...

To test the hypothesis that eastern red cedar (Juniperus virginiana L.) is allelopathic, seedling establishment of five herbaceous prairie species was evaluated by growing seeds in soil collected beneath and adjacent to a stand ofthis tree species. While four species showed no significant effect, the gennination of one species, finger coreopsis (Coreopsis pa/mata Nutt.), was significantly reduc...