A pine tree can be identified by its size, form, bark, cones and growing conditions. Some of the main indicators, however, are in the needles. Pine needle identification comes from careful consideration of four distinct aspects of this evergreen foliage of the genus pinus.
Pine trees feature needles that come in bundles termed fascicles. The pine will have between two to five needles per bundle, which can vary by species but most of the time it is a set number. For example, the ponderosa pine (pinus ponderosa) may have two or three needles per bundle on the same tree, while the eastern white pine (pinus strobus) features five needles per bundle. A tree like the longleaf pine (pinus palustris) has its needles in bundles of three throughout most of its range, except for along the Gulf coastal region, where they often occur in groups of five.
The length of pine needles is an important key to determining what species they belong to. Each species has parameters for the length of their foliage. Virginia pine (pinus virginiana) needles are about 3 inches long, according to the University of Connecticut Plant Database, while those of longleaf pine are between 10 and 15 inches long, making them unmistakable. The loblolly pine's (pinus taeda) needles grow to between 5 and 9 inches. As a rule, the longer the needles are, the easier it is to pinpoint a species. When a pine has shorter needles, as many do, the other factors used to recognize a species come into play.
Use your sense of touch to help you identify pine needles. Feel their texture and determine if they are soft and flexible, or stiff when you try to bend them. Among the pines with soft needles that yield to the touch are types like the eastern white pine and the pond pine (pinus serotina). Those with very stiff needles include species such as the jack pine (pinus banksiana) and the slash pine (pinus elliotii).
Observation of pine needle colors can help you identify the tree, but only with specific species, since nearly all pine needles, with the exception of certain cultivars, are some shade of green. For instance, the needles of the red pine (pinus resinosa) are a very dark color green, according to the "National Audubon Society Field Guide to Trees: Eastern Region." Those of the pitch pine (pinus rigada) are more of a yellow-green hue.