Remnant Forest Stands at a Prairie Ecotone Site: Presettlement History and Comparison with Other Maple-basswood Stands

The maple-basswood community type has long been associated with the "Big Woods" of Minnesota and adjacent Wisconsin, although this community type also exists in discontinuous phases within surrounding forest types. This study looks at the apparent most northwestern outlier of the maple-basswood community type, Rydell National Wildlife Refuge (NWR) in Minnesota. Specific goals are (1) to determine if the maple-basswood stands at Rydell NWR existed historically, and (2) to compare the composition of the Rydell NWR stands to maple-basswood "core" sites, as well as other outlier sites. Public Land Survey records for the period between 1872 and 1876 for a 16-township block encom­ passing Rydell NWR indicate that, although this area was dominated by an oak-aspen forest type, a distinct maple-basswood region existed prior to European settlement and this had escaped disturbance from fire and wind. Present-day stand composition data from six Rydell stands are compared with published data from other maple-basswood stands, using detrended correspondence analysis. A strong geographic pattern is indicated in the ordi­ nation diagram, which is attributed to differences in September precipitation and actual evapotranspiration between the sites. Local-scale environmental gradients act to modify the dominant climatic trend on composition, however, as some Rydell stands plotted close­ ly to the core region in ordination space, whereas other Rydell stands demonstrated greater similarity to oak and aspen stands in North Dakota. [