Pinus resinosa can be
recognized by the long pairs of fascicled needles and the
reddish bark forming smooth plates. The needles are usually
greater than 10 cm long. Only P. nigra also has such
long needles in fascicles of 2, but the bark is darker and
tends not to form smooth, reddish plates. Fresh needles
of P. resinosa will generally snap cleanly when bent
double, but needles of P. nigra do not break cleanly.
It takes a bit of practice to learn to apply this technique,
but it is very useful for young trees for which the bark
is inconclusive. Cones of the two species are similar.
Pinus resinosa is a large
native tree of dry habitats. It is a common tree of plantations,
but is not often used as a street or yard tree. Pinus
nigra is a horticultural species most often planted
in yards and does not escape from cultivation. In Wisconsin
P. resinosa is found nearly throughout the state,
except for a few southeastern counties.