Vascular Plant Propagule Banks of Six Eastern Hemlock Stands in the Catskill Mountains of New York

Abstract

eastern hemlock (Tsuga canadensis) stands in the Catskill Mountains of New York. Soil samples were collected and observed in a glasshouse; germinants were identified and removed over a one year period. Yellow birch (Betula alleghaniensis) seeds, evergreen woodfern (Dryopteris intermedia) spores, and hay-scented fern (Dennstaedtia punctilobula) spores germinated in abundance from the propagule banks (means of 722, 2858, and 296 m-2, respectively) even though hay-scented fern only occurred in the understory of one stand. Seed densities were intermediate and propagule species richness values were low compared to previous studies of northeastern forests. Existing vegetation was also characterized; hemlock was the dominant tree species in all stands (6787% of basal area), with lesser abundances of red maple (Acer rubrum), yellow birch and/or American beech (Fagus grandifolia). Striped maple (Acer pensylvanicum), red maple, yellow birch, evergreen woodfern, shining clubmoss (Lycopodium lucidulum), and common wood sorrel (Oxalis acetosella) occurred in understories of most stands. Understory vegetation and propagule banks indicated potential stand replacement by evergreen woodfern and, eventually, yellow birch in the event of a major disturbance leading to hemlock mortality. However, hay-scented fern could become abundant if woody species are over-browsed by white-tailed deer.