An oak tree represents one of the major divisions of trees -- the deciduous, or hardwood trees. A pine tree is a member of the softwood, or conifer trees. The two types have many differences that help distinguish them from each other. To tell an oak from a pine, study the tree's shape, flowers, leaves and seeds.
Stand back and study the tree's overall shape. Pine trees have a cone or Christmas-tree shape, with the longest branches at the bottom and the shortest at the top. Oak trees resemble the "lollipop" shape drawn by children, like a ball sitting on a stick. You can tell a pine from an oak even if the tree is dead and has no greenery.
Inspect the leaves of a twig. Oak trees have broad, flat leaves on small stalks. Pine trees have long, needle-like leaves in bunches instead of singly.
Look up into the tree for flowers in the spring and early summer. Pine trees do not produce flowers, but oaks produce small clusters of green flowers on hanging stems. If you see flowers, the tree is not a pine.
Search for seeds, either in the tree or on the ground under the tree. Oak trees produce large numbers of acorns, little ball-like nuts that grow with a cap where they attach to the tree. A pine produces a small number of cones, each containing many seeds. When fresh, the cones are solid, but as they dry, the cones open and spread apart.