Look for the number of needles that come out of the same spot on a twig. If a twig bears needles in groups of two, three, or five, you can safely call it a pine. If the twig carries its needles singly, it’s a good bet you’ve got a fir or a spruce. Pull off a needle, and roll it between your fingers. If it feels flat and doesn’t roll easily, it’s a fir. If the needle has four sides and, thus, rolls easily between your fingers, it’s a spruce.