We studied the forest structure and dynamics of the 26 ha College Woods Natural Area (CWNA), Durham, NH. The CWNA is dominated by Tsuga canadensis, but includes a remnant cohort of ca. 300 y old Pinus strobus and abundant mid-tolerant hardwoods. Our primary objectives were to: estimate the recruitment years of four mid-tolerant hardwoods, Acer rubrum, Betula lenta, Quercus rubra, and Q. velutina; relate the temporal appearance and population structure of these species to local disturbance history; and compare our results to other old forests in central New England. We hypothesized that recruitment of mid-tolerant hardwoods at the CWNA was associated with major 20th century windstorms and was limited to within 25 y post disturbance. We used plot sampling to describe densities and size structures of all tree species in the stand. Both Tsuga canadensis, the most abundant species, and Fagus grandifolia were represented in all diameter classes, whereas the mid-tolerant hardwoods were poorly represented in both the smaller and larger size classes. We took increment cores from a sample of trees of each mid-tolerant species and estimated a recruitment year for each individual. We then related recruitment years of each species to local disturbance history. Age estimates suggest that most individuals recruited after 1900 and that recruitment was associated with disturbances, including logging between 1895 and 1919, and the hurricanes of 1938 and 1954. After 1960, there was little recruitment of mid-tolerant tree species, probably due to canopy closure and lack of additional disturbance. The dynamics of mid-tolerant species in the CWNA were similar to those in an old Tsuga–Pinus stand at the Harvard Tract, 125 km to the west, as well as in other mature stands in central New England, suggesting regionally consistent responses to disturbance. Despite the current dearth of recruitment, future regeneration of these species in College Woods is likely, if not due to severe windstorms, then to the imminent loss of the Tsuga canadensis–Fagus grandifolia canopy to introduced insects and pathogens.

Kalmia latifolia has declined in southern New England and other parts of its range in recent decades. This long-term decline is generally attributed to abiotic forces (i.e., low light levels in maturing forests) with little attention to the possible role that top-down effects from ungulate herbivory may be playing. We examined the extent to which mature K. latifolia is capable of sprouting under a relatively undisturbed forest canopy—both after severe stem injury and when uninjured—and tested the hypothesis that, in areas with high deer densities, herbivory may exceed abiotic forces in controlling the dynamics of K. latifolia. A block design experiment with white-tailed deer (Odocoileus virginianus) exclusion and control as treatments and landscape position (hilltop and low slope) as block was established in 2008. Canopy openness was measured in the two treatments within each block using hemispherical canopy photos. Survival and sprouting vigor of cut and uncut K. latifolia stems were monitored over 4 years and analyzed using Bayesian Information Criteria model selection with deer herbivory, percent canopy openness, and slope position as predictor variables. Canopy openness and slope position were important drivers of adult K. latifolia survival and sprouting capacity, whereas deer herbivory and slope position were the most important drivers of sprouting vigor on cut stems. Our results suggest that in a relatively undisturbed forest with high deer densities, herbivory does not exceed abiotic factors in determining adult K. latifolia vigor over the short term, but herbivory and slope position are more important than light in determining sprouting vigor after stem cutting.

Herein, we provide a detailed map and a list of specimens we have examined of Eleocharis mamillata in North America. No chromosome counts have been published for North America under the name E. mamillata. However, the n  =  16 chromosome number reported under E. macrostachya from the Queen Charlotte Islands in British Columbia by Taylor and Mulligan (1968) applies to E. mamillata because the voucher specimens, originally labeled E. macrostachya, are actually E. mamillata. Eleocharis mamillata was confused until recently with E. palustris and E. macrostachya in North America and with E. palustris in Europe. It is readily distinguished from the similar E. palustris, especially by perianth bristle number, stomate morphology, and tubercle always sessile. Descriptions and images of micro-morphological characters of the epidermis of members of the E. palustris complex have been published for Europe but not for North America. We provide descriptions and images of fruits and epidermises of selected specimens of E. erythropoda, E. macrostachya, E. mamillata, and E. palustris from the central U.S. region.

Coastal plain ponds support many plant species that have been designated as threatened due to human alteration of the hydrology and nutrient availability. Understanding how these species respond to environmental gradients at multiple spatial scales can support conservation efforts. I examined the relationship between plant species composition and environmental variables that operate at two spatial scales: within (local-scale) and among (broad-scale) 18 coastal plain ponds on the island of Martha's Vineyard, Massachusetts. Patterns in species composition occurred at both local and broad scales. Elevation along the water-depth gradient was the only local factor strongly correlated with species composition. Significant broad-scale environmental factors included surficial geology, hydrology, and specific conductance of pond water. Overall patterns in vegetation species composition and abundance were more closely related to broad-scale environmental variables than to local environmental variables, suggesting that pondshore vegetation is largely determined by variables that are expressed at the broad scale. Conservation organizations concerned with protecting the coastal plain pond ecosystem should, therefore, protect a network of ponds that captures the full range of environmental variability, because ponds that vary in hydrologic regime, surficial geology, and water salinity exhibit significantly different patterns in species composition.