Plants

Pine trees are native to the Northern Hemisphere and can be found in places like Eurasia, Canary Islands, Scotland, Russia, Phillippines, Norway, Africa, and North America. Though they are not commonly grown here they have been introduced in subtropical and temperate portions of the Southern Hemisphere, including Chile, Brazil, Australia, and New Zealand, where they are grown widely as a source of timber, and some are becoming invasive species.

Pines are evergreen and resinous trees (rarely shrubs) growing to 3–80 m tall, with the majority of species reaching between 15-45 m tall. The smallest are Siberian Dwarf Pine and Potosi Pinyon, and the tallest, Sugar Pine. Pines are long-lived, typically reaching ages of 100–1,000 years, and some even longer; the longest-lived is Great Basin Bristlecone Pine, where one individual at 4,839 years (2007) is the oldest living organism in the world.

The bark of most pines is thick and scaly, but some species have thin, flaking bark. The branches are produced in regular very tight spiral but appearing like a ring of branches arising from the same point. Many pines produce just one such whorl of branches each year, from buds at the tip of the year’s new shoot, but others produce two or more whorls of branches per year.

The spiral growth of branches, needles and cone scales are arranged in Fibonacci number ratios. The new spring shoots are sometimes called “candles”; they are covered in brown or whitish bud scales and point upward at first, then later turn green and spread outward. These “candles” offer foresters a means to evaluate fertility of the soil and vigour of the trees.

Pines grow well in acid soils, some also on calcareous soils; most require good soil drainage, preferring sandy soils, but a few will tolerate poorly drained wet soils. A few are able to sprout after forest fires, e.g. Canary Island Pine. Some species of pines, e.g. Bishop Pine, need fire to regenerate and their populations slowly decline under fire suppression regimes.