A Quantitative Description of the Vegetative Phenology of Herbs in a Northern Hardwood Forest

The vegetative phenology of populations of nine common herbs in a northern hardwood forest was measured quantitatively, using a method developed for resolving important details of phenological patterns. The species may be divided into four different phenological types: vernal photosynthetics (Erythronium americanum and Claytonia caroliniana), summer greens (Uvularia sessilifolia and Clintonia borealis), late summer species (Dennstaedtia punctilobula and Aster acuminatus), and semievergreens (Oxalis montana and Dryopteris spinulosa var. intermedia contrasted with D. spinulosa var. americana). Interspecific differences among and within phenological types and intraspecific variations along an elevational gradient are described in terms of yearly timing of development and senescence, durations of stages, and population synchrony. Concurrent measurements of environmental factors suggest interpretations of adaptive significances of the phenological patterns.