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