One more suggestion and then I'm done...
Persian Parrotia -- this is a beautiful tree with unusual upright or spreading oval form and texture. It’s fall color is a breathtaking mix of yellow, orange and red. The bark is an interesting exfoliating gray, green, white and brown.
Height:
20-30 ft. (6-9 m)
Spacing:
20-30 ft. (6-9 m)
Hardiness:
USDA Zone 4a: to -34.4 °C (-30 °F)
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
Sun Exposure:
Sun to Partial Shade