Pine Trees

Pines are some of the best known plants around the world. They possess huge economic importance through the timber trade and are easily identifiable due to their characteristic cone-shaped growth form and needle-like leaves.

The pines are a family of around 250 woody, seed producing plants. They include conifers such as cedars, spruces, firs and pines. Of all the conifers, the pines have one of the largest distributions although they are found almost entirely in the Northern Hemisphere.

Growth form

PinesPines can be either trees or shrubs. They are all woody, branching plants and grow into the iconic cone shape that pines are famous for. From the top of the tree or shrub, a single ring of new branches each year which creates a gradual increase in length from the newest to oldest branches.

They typically have thick bark and possess needle-like leaves and hardened cones. Most species are evergreen and their leaves are typically long-lived. Leaves of the bristlecone pine, Pinus longaeva, are known to live for up to 40 years.

Distribution of pine trees

Pines are naturally found almost exclusively in the Northern Hemisphere. They are found through much of North America, China, South-East Asia, Russia and Europe and have one of the largest distributions of any conifer family.

Pine trees are the dominant plants in many cool-temperate and boreal forests. They are particularly successful in cold areas where broad-leaved plants are unable to survive such as the boreal forest and at high altitude.

Ecology of pine trees

Pines are well adapted to life in cold environments and in nutrient poor soils. Their growth form helps to reduce the amount of snow each branch must support over winter and prevents branches from falling off. Often the fallen needles of pines will form a dense mat on the forest floor and prevent other plants growing underneath them. Often being evergreen plants, pines can form a well-developed canopy and reduce the amount of light penetrating to the forest floor. This again prevents other plants growing underneath pines in pine forests.

Pines enjoy receiving high levels of light and can struggle to survive in shaded areas. They also struggle to compete with broad-leaved plants in productive areas such as tropical rainforests.

Many species have the ability to withstand burning. Their thick layer of bark helps to protect the tree during fires and prevent burning of vulnerable woody tissue.

Diversity and taxonomy

Pine treesThere is estimated to be around 250 species of pines throughout the world. They are the most diverse and abundant family of conifer in the world, especially so in the Northern Hemisphere.

The pines form a family of conifers called Pinaceae. The family Pineceae sits within the order Pinales and the sub-class Pinidae. It includes a total of 11 genera which include the spruces, cedars, firs, pines and more.

Evolution of pine trees

Pines are thought to have evolved around 153 million years ago, although estimates do vary quite widely. The genus Pinus which includes some important timber species is thought to have diverged from other pines approximately 95 million years ago.

Forestry

Timber and paper industries around the world are built around the growth of planted pine forests. Timber is an essential building material all around the world, both in first and third world countries; and paper has been used for various purposes for hundreds of years. Pines are the dominant trees grown in the majority of countries for both the timber and paper industries and have been critical in both of these multi-billion dollar industries.


Interesting facts

  • The bristlecone pine is the longest living species of plant on Earth, living for over 4,700 years.
  • Pinus radiata has been planted all around the world for timber but was originally only native to a few very small areas on the coast of California and Mexico.

Last edited: 22 May 2015

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