Pine trees can be identified by examining their needles, bark, cones and growth form and comparing the results to a field guide or dichotomous key. Additionally, considering the geographic location of the trees can reduce the list of possible species. For example, loblolly pines are restricted to the southern United States, while ponderosa pines are only found in the western United States.
Pine trees have long, narrow leaves that are arranged in discrete bundles. One of the first things to determine when examining pine trees is the number of needles in each bundle. Most pine trees have groups of two, three or five needles. Combining the geographic area in which the tree is found with the number of needles in each bundle dramatically narrows the potential species. For example, if the pine tree is in the southern United States, and its needles are bundled in groups of five, it is a white pine. Alternatively, if a tree in the same region has needles in bundles of two, it may be a shortleaf, loblolly, longleaf or Virginia pine. To further narrow the possibilities, consider the bark, cones and growth form of the tree.
Not all characteristics of pine trees are helpful for identification purposes. For example, the height of a tree is rarely a valid method for identification, as height depends on a variety of factors, including the amount of annual precipitation and the type of soil in which the tree grows.