Presettlement tree distributions and forest types of northeast Ohio, USA, mapped with species distribution models

European colonization radically transformed the landscapes of eastern
North America. Understanding this legacy is vital to managing current
ecological communities. To do so requires spatially explicit information
about presettlement vegetation. Here we test the ability of species
distribution models, which have rarely been used with historical data like
land survey records, to generate useful predictions of presettlement tree
distributions. These models also allow us to assess pre-disturbance
vegetation-environment relationships. Location: Cuyahoga County, Ohio, USA
Methods: Generalized linear models, generalized boosting models, random
forests, and maximum entropy models related the distributions of 17 tree
taxa to elevation, slope, aspect, and soil type, based on 4234 tree
observations from circa-1800 surveys. Cluster analysis defined forest
types and created a prediction map of forest types using random forests.
Results: This study generated high-resolution predictions of presettlement
tree distributions. Fagus grandifolia and Carya spp. were predicted to
have found suitable habitat in over half the area. Elevation was by far
the most important predictor, followed by slope. Many taxa were more
likely to occur at higher elevations, corresponding to the Allegheny
Plateau, while others followed river valleys. Broadly, 51% of the county
was predicted to support forest types with Fagus grandifolia and/or Acer
spp., and 48% of the county was predicted to support forest types with
Quercus spp., Carya spp., and/or Castanea dentata. Conclusions: This study
demonstrates that species distribution modeling with historical data
provides insights into presettlement vegetation and vegetation-environment
relationships. Our results reveal striking ecological patterns not
apparent in today’s landscape, such as the sharp difference in vegetation
between the Central Lowland and Allegheny Plateau. The maps created here
offer a historical perspective that can inform conservation, education,
and further research.