Very smooth (ignore mature trees lowest parts)

many colors, each in own asymmetric patches
American sycamore Platanus occidentalis

two-color (gray with lots of lenticels);  huge leaf scars thickly C-shaped, filled by large bud
tree of heaven Ailanthus altissima

one-color (light gray),     muscular ribs
American hornbeam / ironwood Carpinus caroliniana

one-color (light gray), no muscular ribs, often w/carved graffiti
American beech Fagus grandifolia

one-color (red or cinnamon), may peel away in thin sheets revealing green cambium
Pacific madrone Arbutus menziesii

Deep vertical fissures or ribs

very thick vertical ribs, looks covered with warts or puffy paint
hackberry Celtis occidentalis

🚧 under construction
black willow Salix nigra

Separates into features that hang away from the trunk

burnt potato chips/crisps
mature 🍒︎ black cherry Prunus serotina

thin layers, rolling up trunk in strips, white over orange
American white birch Betula papyrifera

bark=thick rigid shaggy gray strips, barely attached
mature shagbark hickory Carya ovata