with needles that are . . .

flat and pliable or

4-sided and stiff, sharp, and twig=rough where needles fall off   >   spruce genus Picea or

round with axial groves, segmented, tips have projections, looks like horse hair   >   🇦🇺 Australian pine Casuarina equisetifolia :

Needles are flat and pliable

and splay . . .
left + right + up + down + all angles or
left + right :

Needles splay left + right

undersurface=not whitish;  shorter toward end of twig, shed with them   >   Bald Cypress Taxodium distichum

undersurface=whitish;  lengths differ from each other;  western North America   >   western hemlock Tsuga heterophylla
undersurface=whitish;  lengths differ from each other;  eastern North America   >   eastern hemlock Tsuga canadensis

undersurface=whitish;  northern Canada or USA;  fragrant   >   balsam fir Abies balsamea
undersurface=whitish;  USA Appalachia   >   Fraser fir Abies fraseri