Table 1. Species groupings of herbs used for data analysis.
Definitions:
  • Generalist species are common and found in a wide variety of habitats.
  • Dispersal-limited species do not have adaptations for long-range dispersal (such as vertebrate-dispersed berries or wind-dispersed fruits).
  • Weeds are species that are most abundant in disturbed areas, including forest edges. Many of these species are exotics.
Generalist Species

Arisaema triphyllum, Aristolochia macrophylla, Cornus florida, Sanicula canadensis, Sanicula gregaria, Senecio aureus, Smilacina racemosa, Viola sororia

Dispersal-limited Species

Asarum canadense, Dentaria diphylla, Disporum lanuginosum, Disporum maculatum, Hepatica acutaloba, Sanguinaria canadensis, Tiarella cordifolia, Trillium erectum, Trillium rugelii, Trillium undulatum, Uvularia perfoliata, Uvularia pudica, Viola canadensis, Viola hastata, Viola pubescens

Weed Species

Ambrosia artemisiifolia, Amphicarpa bracteata, Celastrus orbiculatus, Circaea lutetiana, Clematis virginiana, Cryptotaenia canadensis, Desmodium nudiflorum, Fragaria virginiana , Galium aparine, Geum virginianum, Glecoma hederacea, Lactuca biennis, Lindera benzoin, Lonicera japonica, Pilea pumila, Polygonum cespitosum, Polygonum persicaria, Ranunculus acris, Ranunculus bulbosus, Ranunculus hispidus, Ranunculus recurvatus, Rosa multiflora, Rubus allegheniensis, Rubus species, Salvia lyrata, Solidago nemoralis, Solidago species, Stellaria media, Taraxacum officinale

Table 2. Species groupings of trees used for data analysis.
Definitions:
  • Early successional species - Species that are tolerant of high light conditions and poor, disturbed soils characteristic of old fields and pastures.
  • Late successional species - Shade-tolerant species that make up a large proportion of established forest.
Late Successional Species

Acer pensylvanicum, Acer saccharum, Aesculus octandra, Carya cordiformis, Carya glabra, Carya ovalis, Carya tomentosa, Castanea dentata, Fagus grandifolia, Ilex montana, Juglans cinera, Magnolia acuminata, Magnolia fraseri, Nyssa sylvatica, Ostrya virginiana, Pyrularia pubera, Quercus alba, Quercus prinus, Quercus rubra, Quercus velutina, Rhododendron calendulaceum, Rhododendron maximum, Tilia americana

Early Successional Species

Betula lenta, Crataegus species, Juglans nigra, Lindera benzoin, Liriodendron tulipifera, Malus spp., Morus rubra, Platanus occidentalis, Prunus americana, Prunus serotina, Robinia pseudo-acacia, Sambucus canadensis, Sassafras albidum, Ulmus rubra



Table 3. An analysis of variance of the effects of forest age and tree characteristics on forest herbs.

Forest age refers to time of establishment (pre-1950, post-1950). Site accounts for differences due to landscape context. Tree diversity (species richness) and size (mean dbh) were measured in the same 0.10 ha plot as herbs.

Independent Variables
Species richness for: Age Site Tree diversity Tree Size
All species * *
Generalists * *
Weeds * * *
Dispersal-limited * * *

* = P<0.05. Blank cells indicate that effects were not significant.

Table 4. Correlations between herb diversity and tree diversity. Pearson correlation coefficients are reported. Significant correlations (P <0.05) are shown in bold text.
Herb Species Richness
All species Generalists Weeds Dispersal-limited
Species richness 0.26 0.06 -0.31 -0.04
Shannon diversity 0.15 -0.07 -0.54 0.03
Cumulative dbh 0.12 -0.11 -0.44 0.45