Pinus, the genus that contains the pine tree in North America, includes many important timber and ornamental species. Pines occur across North America as well as Eurasia as native trees, with many growing to a large size. The pines have specific features such as their evergreen foliage and bark that make them able to serve as landscaping tools.
The leaves of a pine tree are evergreen needles, which grow from the branches in bundles. The number of needles in each bundle is a key to pine tree identification. For example, the spruce pine (Pinus glabra) has needles in bundles of twos, while the eastern white pine (Pinus globrus) has bundles of five needles each emerging from its branches. The needles differ in length and texture, with some long and rigid, such as the stiff 8- to 12-inch-long needles on a slash pine (Pinus elliottii) versus the flexible, much shorter needles of shortleaf pine (Pinus echinata). Pine needles come in an array of greens, such as those of pond pine (Pinus serotina), a species with needles that are a dark shade of greenish-yellow.
Pine bark is often one of the more interesting and attractive parts of the tree, with assorted species of pines appealing to landscapers because of the bark's color and texture. Pine bark will vary between species, with some pines possessing furrowed and ridged bark while others have bark resembling scaly plates, according to the "National Audubon Society Field Guide to Trees: Eastern Region." A tree such as red pine (Pinus resinosa) has ornamental value because its thick, scaly bark has a reddish-gray hue. Virginia pine (Pinus virginiana) has red-brown bark divided into flat plates by "shallow fissures," notes the Nearctica website.
Male and female parts occur on the same tree in the case of the pines, with the male parts being herbaceous in nature, but the female parts taking the form of woody cones. The female cones contain the tree's seeds, protected within the structure. Pine cones often add flair to the tree, with some being so large as to be easily noticeable. The cones of the sugar pine (Pinus lambertiana) can reach lengths in the range of 26 inches, notes "Trees of North America." While many pines develop elongated cones of this type, others such as loblolly pine (Pinus taeda) have a much more compact cone, with the individual scales on the cone tipped with a sharp point similar to a bristle. Pine cones can be problematic when they finally do fall from the limbs after they open up and release their seeds. At that point, they may become a litter problem, awaiting you to rake them up and dispose of them.