A Comparison of Early-European Settlement and Present-Day Species Mingling Patterns in the Eastern Deciduous Forest, USA

Mingling indices describe whether an individual tree is more likely to grow near others of the same or different species. We examined whether changes in land use associated with European settlement of the United States altered the mingling indices of five species: basswood ( Tilia americana ), black walnut ( Juglans nigra ), butternut ( Juglans cinerea ), sugar maple ( Acer saccharum ), and sycamore ( Platanus occidentalis ). At the time of European settlement, butternut and black walnut grew intermingled with other species, and sycamore grew near other sycamores. Basswood and sugar maple were intermediate in their mingling. Substantial changes in land use associated with European settlement resulted in shifts in mingling indices for sugar maple and basswood in present-day forests; however, basswood, black walnut, and butternut did not experience a change. This research was a novel application of the mingling index at two time periods to quantify human impacts on forest structure.