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 the Adirondack Mountains of New York, USA: old growth; partially cut, unevenaged with 40-50 cm maximum residual diameters; and maturing, even-aged, 90-100 yr old, postfire. Downed CWD (stumps Յ1 m tall and logs) volumes in the old-growth, partially cut, and maturing stands were 139, 69, and 61 m 3 /ha, respectively. Large (Ն50 cm diameter) CWD comprised 17%, 13%, and 4% of the total downed CWD volume in the old-growth, partially cut, and maturing stands respectively. Approximately one-half the large CWD in the partially cut stands was in the form of cut stumps. Standing CWD (stumps Ͼ1 m tall and standing dead trees) basal areas averaged 8.6, 1.2, and 4.1 m 2 /ha in the old-growth, partially cut, and maturing stands, respectively. Basal area of large (Ն50 cm diameter) standing CWD averaged 70%, 0%, and 5% of the total in the old-growth, partially cut, and maturing stands. Both downed and standing CWD loads were influenced by mortality due to beech bark disease. Decay distributions of downed CWD were similar in all stand types. The old-growth stands averaged 55 live trees Ն50 cm dbh/ha, including 14 trees Ն70 cm dbh/ha. The partially cut stands contained 5 trees Ն50 cm dbh/ha, with none Ͼ55 cm dbh. The maturing, even-aged, stands averaged 1.3 stems Ն50 cm dbh/ha in the postdisturbance cohort but also had ϳ8 postfire residuals/ha with diameters up to 70 cm dbh.Implementing forest ecosystem management guidelines to emulate the structural characteristics of old-growth northern hardwoods should retain at least 16 live trees/ha Ն50 cm dbh including 6 trees/ha Ն70 cm dbh. Target levels for downed CWD volume would be less (perhaps 25% less) than the 139 m 3 /ha reported here, considering the influence of beech bark disease on the stands we studied. These goals can be accomplished by increasing diameter limits in selection systems, by extending even-aged rotations beyond 100 yr, and implementing ''reserve shelterwood'' cuts that retain large trees in regenerated, even-aged stands. Retaining large trees will provide more future options to increase the proportion of large standing and downed CWD in managed stands.

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 the Adirondack Mountains of New York, USA: old growth; partially cut, unevenaged with 40-50 cm maximum residual diameters; and maturing, even-aged, 90-100 yr old, postfire. Downed CWD (stumps Յ1 m tall and logs) volumes in the old-growth, partially cut, and maturing stands were 139, 69, and 61 m 3 /ha, respectively. Large (Ն50 cm diameter) CWD comprised 17%, 13%, and 4% of the total downed CWD volume in the old-growth, partially cut, and maturing stands respectively. Approximately one-half the large CWD in the partially cut stands was in the form of cut stumps. Standing CWD (stumps Ͼ1 m tall and standing dead trees) basal areas averaged 8.6, 1.2, and 4.1 m 2 /ha in the old-growth, partially cut, and maturing stands, respectively. Basal area of large (Ն50 cm diameter) standing CWD averaged 70%, 0%, and 5% of the total in the old-growth, partially cut, and maturing stands. Both downed and standing CWD loads were influenced by mortality due to beech bark disease. Decay distributions of downed CWD were similar in all stand types. The old-growth stands averaged 55 live trees Ն50 cm dbh/ha, including 14 trees Ն70 cm dbh/ha. The partially cut stands contained 5 trees Ն50 cm dbh/ha, with none Ͼ55 cm dbh. The maturing, even-aged, stands averaged 1.3 stems Ն50 cm dbh/ha in the postdisturbance cohort but also had ϳ8 postfire residuals/ha with diameters up to 70 cm dbh.Implementing forest ecosystem management guidelines to emulate the structural characteristics of old-growth northern hardwoods should retain at least 16 live trees/ha Ն50 cm dbh including 6 trees/ha Ն70 cm dbh. Target levels for downed CWD volume would be less (perhaps 25% less) than the 139 m 3 /ha reported here, considering the influence of beech bark disease on the stands we studied. These goals can be accomplished by increasing diameter limits in selection systems, by extending even-aged rotations beyond 100 yr, and implementing ''reserve shelterwood'' cuts that retain large trees in regenerated, even-aged stands. Retaining large trees will provide more future options to increase the proportion of large standing and downed CWD in managed stands.

The objective of this study was to assess the influence of substrate heterogeneity on epiphytic bryophyte communities in northern hardwood forests of varying disturbance histories. Specifically, we compared bryophyte abundance (m2·ha–1) and community composition among partially cut; maturing, 90- to 100-year-old, even-aged; and old-growth northern hardwood stands in Adirondack Park, New York, U.S.A. Total bryophyte cover from 0 to 1.5 m above ground level on trees [Formula: see text]10 cm diameter at breast height (DBH) did not differ among the three stand types. However, bryophyte community composition differed among host tree species and among stand types. Communities in partially cut and maturing stands were dominated by xerophytic bryophytes (Platygyrium repens, Frullania eboracensis, Hypnum pallescens, Brachythecium reflexum, Ulota crispa), while old-growth stands contained a greater representation of calcicoles and mesophytic species (Brachythecium oxycladon, Anomodon rugelii, Porella platyphylloidea, Anomodon attenuatus, Leucodon brachypus, Neckera pennata). This mesophyte-calcicole assemblage occurred in all stand types but was limited by the abundance of large-diameter (>50 cm DBH), thick-barked, hardwood host trees (Acer saccharum Marsh., Tilia americana L., Fraxinus americana L.). This study suggested that epiphytic bryophyte diversity can be sustained and enhanced in managed northern hardwood forests by maintaining host tree species diversity and retaining large or old, thick-barked residual hardwood stems when applying even-aged and uneven-aged silviculture systems.