The Iowa State University Extension explains one way to differentiate between a spruce tree and a pine tree is to look at the needles. Spruce needles grow directly from a branch individually, and pine needles grow in bunches of two, three or five. Also, the bark of a spruce tree is rough rather than smooth, which sets them apart from fir trees.
The needles of spruce trees are sharp, pointed and square. One reliable way to identify a spruce tree is to take a needle and roll it between two fingers. If the needle rolls easily between the fingers, it is a spruce tree. Fir tree needles are flat, are soft and don't roll easily between fingers.
Spruce needles are attached to their branches with stalk-like projections. When the tree sheds its needles, these projections remain on the tree. The color and length of needles aren't reliable indicators for identifying spruce trees because these characteristics vary.
Cones of spruce trees are long and flexible rather than rigid. The scales on spruce tree cones are thinner and less woody than those on pine trees. These cones grow to between 8 and 26 inches long, and their size varies from tree to tree.