The objective of this study was to establish baseline data for the structure and dynamics of an old-growth beech (Fagus grandifolia)-sugar maple (Acer saccharum) woods in northeastern Ohio before the anticipated future impacts of disturbances such as beech bark disease. Several parameters were selected for study based on their likelihood of being influenced by these disturbances including: (1) species composition; (2) mortality and growth rates of trees, overall, by species and by size class; (3) canopy replacement patterns; (4) coarse woody debris (CWD) characteristics; and (5) the understory response to existing openings and its implications for change in the forest under present conditions. This study extends our understanding of beech-sugar maple old growth because our site is, perhaps, the most northeasterly one not yet affected by beech bark disease and because it is the only studied site influenced by weather conditions generated by Lake Erie.
The overall annual mortality rate (from 1992 to 1997) of 2.3% was higher than that reported for other old-growth woods (1%). Mortality was highest for the large canopy stems (≥50 cm dbh) of beech and the subcanopy stems (10–25 cm dbh) of sugar maple. Growth rates decreased with stem size for beech, but increased with stem size for sugar maple. Over the 5 y period beech decreased in relative basal area and relative density whereas sugar maple increased in both measures. CWD mass (35.9 Mg ha−1) was similar to other old-growth deciduous forests. Beech mortality has been greater than sugar maple mortality for several years. Sugar maple and beech were dominant in the understory although few stems <1 cm dbh were found near treefall gaps. Older gaps had more numerous and larger stems.
Currently, the structure and dynamics of the woods are very similar to other old-growth beech-sugar maple forests of the region. Beech is present in all size classes. However, the number of large beech stems has been declining steadily even though beech bark disease has not yet reached the area.