Pine is one of a huge group of evergreen trees that have needle-like leaves and bear cones. There are about 100 species of pine, almost all of which grow naturally in the northern hemisphere only. Pine trees are found in a wide range of environments but most often grow in sandy and rocky soils. Pine trees are common trees in the western and southeastern mountains of North America, southern Europe and southeast Asia . Some pine trees reach 60 m in height. Others are small and shrub-like.
inoculation
Pine trees bear both male and female cones. The male cones are usually less than 2.5 cm long, while the female cones are larger and have woody scales. When people talk about pine cones they usually mean the female cones. In the spring the male cones produce massive amounts of pollen. The wind carries the pollen to the egg cells attached to the scales of the female cones, and the pollen fertilizes the egg cells, which then develop into seeds. Seeds take one to two years to reach maturity. Most mature seeds of pine species have wing-like parts that cause them to rotate and swim with the wind. Pine seeds can be dispersed up to 90 m away from the mother tree.
economic importance
Pine is the most important source of raw wood in the world. Most pine trees grow quickly and have long, straight trunks. These are ideal for producing raw lumber. Some types of pine produce resin, which is a substance used in making turpentine products, paints, and soaps. The wood of most pine species is an excellent pulp for writing paper. Pine trees are grown for shade, too.
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Main article: Pinus classification
Pine belongs to a group of plants called conifers. All conifers reproduce by means of cones that produce pollen and seeds. Pine trees differ from other conifers in the way their leaves grow. Almost all pines have needle leaves that grow in bunches of two, three, or five leaves on each. The leaves of the rest of the other conifers grow in larger bundles, or the leaves are not in bundles. Conifers close to pine include spruce , larch , and spruce .
distribution
North American pine trees
About 65 species of pine grow in North America. Red pine and American pine are two important species of pine that grow in Canada and the northeastern part of the United States. The red pine's name is derived from its reddish-brown bark. It is considered an important raw wood tree. The American pine grows mainly in sandy lands from the northern Great Lakes region to northwestern Canada.
Frankincense pine thrives in many environments throughout the southeastern United States. It is an important wood tree. It grows rapidly and is common in deserted fields and pastures.
Different types of pines are found at different altitudes in the western mountains of North America. The grizzly pine grows at lower elevations in the Sierra Nevada Mountains and along the California coast.
A group of important pine species grow at elevations slightly higher than that of the grizzly pine. Heavywood pine is common throughout the Rocky Mountains, the eastern side of the Cascade Mountains, and the southwestern United States. This type of pine grows to a height of 40 m, and produces wood of a high quality. Cottage pole pine grows at higher elevations than heavy-wood pine in the Sierra Nevada and Rocky Mountains. The cottage pole pine thrives in sandy lands and its needle leaves grow in bundles of two leaves.
Ballistic pine cones are found at great elevations, and some of these trees are among the oldest living organisms. Some of them are more than 4,000 years old.
Many species of pine grow naturally in a few areas of Southern California. For example, the Monterey pine is endemic to a small area on the California coast. This tree was introduced to the southern hemisphere and is now an important source of raw wood in Australia, Chile, New Zealand and southern Africa.
Pine trees of Europe and Asia
Only a few species of pine grow in northern Europe; Scots pine is probably the most important of these species and has value as a raw timber tree. The Scots pine is the only surviving species after the Ice Ages, and is found in mountainous lands everywhere in Europe from the mountains of Lapland to southern Spain. Scots pine is one of the most beautiful types of pine, and it produces important softwood that has many applied uses, especially in the construction industry. Huge forests of Scots pine still remain in Russia and Northern Europe.
Many species of pine grow in the countries bordering the Mediterranean Sea. Perhaps the most recognizable of these is the fruiting pine with a large, umbrella-like crown. It grows around the northern end of the Mediterranean from Portugal to Asia Minor. The fruit pine has large, almost round, brown cones containing edible seeds. Black pine, also called Austrian pine, is an important source of raw wood in this region. An ornamental tree is also distributed around the world, the closest related being the Corsican pine. Corsican pine is less hardy but grows faster and more massive than the previous type. Its native home is Corsica, southern Italy and Sicily. The wood produced from this species is used, inter alia, to make pulp used in the manufacture of writing paper. The Aleppo pine is the most widespread in the Mediterranean region, and it grows from Spain and North Africa and near the Strait of Gibraltar to the mountains of Palestine and Lebanon.
About 15 species of pine grow naturally in Southeast Asia and Japan, most of them in mountainous regions. The Siberian pine is an important species of pine. This type of pine grows on the Ural Mountains, extending across western and central Siberia to northern Mongolia. The home of the Bhutan pine is the Himalayas. This is an important timber tree and is also cut down to extract the resin from it. It is cultivated in many countries for its decorative value.
The cultivation of special forms of the Japanese white pine is a common feature found in both large public gardens and small gardens in Japan. These trees, in addition to the larger black Japanese pine, are grown as dwarf trees, which is known as bonsai. Japanese black pine is considered one of the commercial varieties of high value and is grown for wood, and resin is grown in some countries, such as Australia, along the coast to repel winds and to stabilize sandy soil. [1]