A pine is any conifer in the genus Pinus of the family Pinaceae.
Pines are among the most commercially important tree species valued for their timber and wood pulp throughout the world. In temperate and tropical regions, they are fast-growing softwoods that grow in relatively dense stands, their acidic decaying needles inhibiting the sprouting of competing hardwoods. Commercial pines are grown in plantations for timber that is denser and therefore more durable than spruce (Picea). Pine wood is widely used in high-value carpentry items such as furniture, window frames, panelling, floors, and roofing, and the resin of some species is an important source of turpentine.
When grown for sawing timber, pine plantations can be harvested after ±22 years, with some stands being allowed to grow up to 30 (as the wood value increases more quickly as the trees age). Imperfect trees (such as those with bent trunks or forks, smaller trees, or diseased trees) are removed in a "thinning" operation every 7–10 years. Thinning allows the best trees to grow much faster, because it prevents weaker trees from competing for sunlight, water, and nutrients. Young trees removed during thinning are used for pulpwood, while most older ones are good enough for saw timber.
The final wood quality can be improved by pruning small branches at ages 5, 7, and 9. Pruning usually goes up to a height of 6 metres. This results in smooth timber with no knots, which is considerably more valuable.
A 18-year-old commercial pine tree grown in good conditions will be about 0.3m in diameter and about 20m high. After 30 years, the same tree will be about 0.6m in diameter and 30m high, and its wood will be worth about three times as much as the 18-year-old tree.
Trees are planted 3–4 m apart, or about 1000 per hectare.