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 (large trees may have buttress roots[?]), 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

bark=thin layers, rolling around trunk in horizontal strips, white over orange
American white birch  Betula papyrifera

bark=covered in burnt potato chips/crisps
mature 🍒︎ black cherry  Prunus serotina

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

bark=thick rigid shaggy gray vertical strips;  in wild, branches and trunk have large smooth thorns[?]
honey locust  Gleditsia triacanthos