pine, common name for members of the Pinaceae, a family of resinous woody trees with needlelike, usually evergreen leaves. The Pinaceae reproduce by means of cones (see cone) rather than flowers and many have winged seeds, suitable for wind distribution. They are found chiefly in north temperate regions, where they form vast forests. The family was apparently more abundant in the mid-Cenozoic era, but it has maintained its population better than other gymnosperms because the trees are more adaptable to cold, dry climates; the reduced leaf surface and deep-set stomata minimize loss of water by transpiration. The family is the largest and most important of the conifers, providing naval stores, paper pulp, and more lumber by far than any other family. In some localities almost pure stands occur, permitting economical lumbering of large numbers of a given type of tree. Of the family's nine genera four are widely dispersed throughout North America and the Old World. Members of all nine genera are represented in horticulture as introduced timber trees or ornamentals. The so-called kauri pine, although pinelike in appearance, belongs to another family (see monkey-puzzle tree).

The True Pines

Pinus (the true pines) is the largest and most widespread genus, characteristic of many north temperate regions (except the plains), especially at lower altitudes, and in a few tropical regions, notably on mountain slopes. Species of Pinus can often be identified by the leaf arrangement, one needle or clusters of from two to five (in all cases enclosed in a sheath at the base) being consistently produced by each type. Many of the pines are economically valuable; from them come the naval stores: pitch (see tar and pitch), turpentine, and rosin. Drying and nondrying oils are also made from the seeds of some pines. Several Mediterranean and American species yield edible seeds (see pine nut).

The ponderosa pine or western yellow pine (P. ponderosa), is a hard pine second only to the Douglas fir as a commercial timber tree in North America. The white pine (P. strobus) has straight-grained soft wood with little resin, used especially for interior trim and cabinetwork. It once grew densely from Newfoundland to Manitoba and over much of the E United States westward to Minnesota, but constant felling and attacks of white-pine blister rust have greatly depleted the stands, especially in the NE United States. The Norway pine, or red pine, (P. resinosa) has a similar range and has also suffered from overcutting. Its wood is somewhat heavier and is suitable for general construction. The Norway pine is frequently used in reforestation programs. The jack pine (P. banksiana), the most northern of the American species, thrives on poor and sandy soils and is much used to colonize areas where more valuable species may later be introduced. Although the trunk is often gnarled, making it unsuitable for good lumber, it supplies much pulpwood and is used locally for rough lumber, fuel, and crating. The Virginia pine (P. virginiana) of the Appalachians and the Piedmont is popular regionally as a Christmas tree. The longleaf pine, or Southern yellow pine (P. palustris) has highly resinous wood used for heavy construction and as a major source of naval stores and pulpwood. It and the faster growing slash pine (P. caribaea) of the same region have gained importance as northern pine stands have been depleted. The latter is widely cultivated in tropical areas with sandy soils. The Scotch pine (P. sylvestris), ranging from Scotland to Siberia and popular as a Christmas tree in the United States, is one of the most valuable timber trees of Europe. The cluster pine (P. pinaster), widespread in S France and in Spain, is the chief European source of turpentine. The Monterey pine (P. radiata) of California has been widely planted in New Zealand and Chile for reforestation.

Other Species in the Pine Family

Abies (fir) species are usually of more northern distribution and found at higher altitudes. Sap-filled "blisters" on the trunks of some species provide balsam. Larix (larch) and Pseudolarix (golden larch, of China) are the only two deciduous genera. Picea (spruce) is the world's most important source of paper. Cedrus (cedar) ranges from the Mediterranean area to the Himalayas; Keteleeria is restricted to E and SE Asia.

Tsuga (hemlock) and Pseudotsuga are native only to North America and E Asia. Pseudotsuga menziesii (the Douglas fir) of W North America, one of the tallest trees known (up to 385 ft/117 m) and the leading timber-producing tree of the continent, is carefully controlled by forestry measures. Its wood, usually hard and strong, is of great commercial importance for construction; it is also commonly used as a Christmas tree in the United States. Named for David Douglas, the tree has many local names, e.g., Douglas spruce, Oregon pine, red fir, and yellow fir.

Classification

Pines are classified in the division Pinophyta, class Pinopsida, order Coniferales.