McGee, G.G. 1998. Structural characteristics of Adirondack northern hardwood forests: Implications for ecosystem management. PhD Dissertation, State University of New York, College of Environmental Science and Forestry, Syracuse, 206pp.

Abstract: The objectives of this research were to: (1) investigate some potential ecological effects of applying forest ecosystem management (FEM) concepts in northern hardwood forests; and (2) propose silvicultural treatments to achieve FEM objectives. Live tree diameter distributions, and abundance and quality of standing and downed coarse woody debris (CWD) were compared among three northern hardwood stand types in Adirondack Park, New York: old growth; partially-cut, uneven-aged; and maturing, even-aged, 90- to 100-year-old. Structural heterogeneity, as measured by live tree diameter distributions, and standing and downed CWD abundance (volume, biomass, surface area) and diameter distributions, was greatest in the old-growth stands. Total epiphytic bryophyte cover did not differ among stand types. Epiphyte communities in old-growth stands had greater representation of mesophytic and calciphilic species that were associated with large-diameter, thick-barked hardwoods (Acer saccharum, Tilia americana, Fraxinus americana). Moisture availability of A saccharum bark increased, and bark drying rates decreased with increasing tree dbh. Limited evidence existed for potential enrichment of stemflow with base cations in relation to tree dbh, and some of these factors may have accounted for the unique epiphytes on large-diameter A. saccharum. Total epixylic bryophyte cover was greatest in the old-growth stands, and differences in epixylic community composition were attributed to species composition of coarse woody debris. No vascular plant species relied exclusively on CWD microsites, although Dryopteris intermedia exhibited greater densities on CWD microsites relative to undifferentiated hardwood forest floor, and some tree species had greater basal area on CWD microsites. Regeneration success of some tree species, and the richness of understory herbs appeared to be more strongly related to stand-level factors (e.g., canopy cover) than CWD microsites. A variety of silvicultural treatments including selection cuts with large (> 50 cm dbh) maximum diameter limits and relatively high residual basal areas, reserve shelterwood cuts that retain seedtrees in regenerated stands, and heavy selection cuts with low residual basal areas will produce coarse-grained canopy characteristics that reflect natural northern hardwood landscapes.