Stand structure and composition in a Northern Hardwood forest after 40 years of single-tree selection

Uneven-aged northern hardwoods of the Great Lakes region are managed primarily through single-tree selection harvesting. We quantified species composition and stand structure after 40 years of single-tree selection in five stands as compared with three stands that were untreated for 40 years. Relative density and importance value of sugar maple significantly increased under single-tree selection, whereas relative density of yellow birch significantly decreased and eastern hemlock remained unchanged. Contemporary seedling and saplings layers were dominated by sugar maple regardless of treatment, but unmanaged stands contained more species. Diameter distribution varied over time and between unmanaged and managed stands. Increasing-q was the most common distribution shape in 2004, and there was no clear trend toward a negative exponential or rotated sigmoid distribution over time. Our results suggest that long-term single-tree selection may result in regeneration of fewer tree species commonly found in this forest type, with potential implications for future stand structure.