Successive buds always 180° around stem, often making stem zig-zag between buds

bark=very thick vertical ribs, looks covered with warts or puffy paint;  often has dark 🍒︎ cherry-like fruit
hackberry Celtis occidentalis

buds=very small, partly hiding beneath twig bark;  often has dry seed capsules
sourwood Oxydendrum arboreum

buds=not hiding :

Buds=centered over leaf scar

side-buds=same width as twig;  twigs=light-brown
mulberry genus Morus

side-buds=wider than twig;  bark=long ■ square-ended strips peel upward
American hophornbeam / ironwood Ostrya virginiana

side-buds=wider than twig;  bark=gray or dark-blue
American hornbeam / ironwood Carpinus caroliniana

Successive buds spiral around stem, with stem NOT zig-zagging

leaf scars=raised;  lenticels=light-colored and raised, conspicuous against dark shiny bark

leaf scars=compact, with 3 bundle scars, centered directly above is side bud scale
poplar/aspen genus Populus

leaf scars=thin crescent;  buds=hairy and blunt; tree=wide
🍎︎ common apple Malus pumila

leaf scars=thin crescent;  buds=wooly tips;  twigs=smooth
🍎︎ wild crabapple Malus coronaria

leaf scars=thin crescent;  buds=wooly tips;  twigs=wooly
🍎︎ prairie crabapple Malus ioensis