For species for which no model information is available (rare, nonnative, or cultivars), shifts in heat and hardiness zones could have a positive effect on about 23 percent of species that are either present in the Chicago area or considered for planting,

Species that are currently marginal for hardiness zone (lowest zone is 5 or higher) may experience benefits from milder winters. Species that are marginal for heat zone (highest zone is 7 or lower) may experience negative effects from hotter summers. Based on this method, 24 species (23 percent of those evaluated) may experience a positive effect from an increase in hardiness zone over the next century (Brandt et al., 2017, table 4). Twelve of these species are currently found in the region according to the Regional Tree Census (Nowak et al. 2013), although some are invasive such as tree of heaven and privet. Twenty-three species (22 percent) may experience a negative effect from an increase in heat zone. Of these, four of them are relatively common in the Chicago Wilderness region: cockspur hawthorn, European alder, Amur maple, and Norway maple.