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 needles that reach 18 in. (45 cm) in length and have been prized for making baskets and as mulch. Its highly resinous wood is used for heavy construction and as a major source of naval stores and pulpwood. It formerly was the keystone of forests that formed a savannalike ecosystem in much of the S United States. The longleaf pine 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.
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