Pinus

Pinus , commonly known as pines , is a genus of vascular plants belonging to the group of conifers and, within this, to the family Pinaceae . It is one of the most important genera, from the forestry point of view, both for the number of species and for the value that many of them have, both in their countries of origin and also when introduced.

Taxonomy

Scientific name

• Pinus L.

Pinus canariensis

^{[1] [2] [3]}

Authors

• Linnaeus, Carl von
• Published in: Species Plantarum 2: 1000–1002. 1753 . (1 May 1753 ) ^[4]

Synonymy

• Apinus Neck. ex Rydb.
• Caryopitys Small
• Ducampopinus A. Chev.
• Leucopitys New.
• Pinea Wolf
• Strobus Opiz ^[5]

Common name

• Pines, pine.

Pinus sylvestris

Type species

• Pinus sylvestris L. ^[6]

Species and subspecies

• Appendix: Pinus species ^[7]

Origin and distribution

Pines are native to the Northern Hemisphere , with only one species found south of the equator on the island of Sumatra (Sumatra pine). In North America they range from 66°N in Canada (Jack pine) to 12°N in Nicaragua (Caribbean pine). The subtropical and tropical mountains of Mexico are home to the greatest diversity of species in this genus, with about 47. The western United States ( California ) is the second most diverse place on earth for pines. In Eurasia they are found from the Canary Islands and Scotland in the west to the Russian Far East , and from the Philippines in the south to 70°N in Norway and Eastern Siberia (Scots pine and Siberian dwarf pine, respectively).

Seven species are native to the Iberian Peninsula and surrounding areas and have survived and developed since ancient times. Pines occur in mountainous areas in North Africa , as well as in the Himalayas and Southeast Asia. Pines have been introduced into temperate and subtropical areas of the Southern Hemisphere , including Argentina , Brazil , Chile , Ecuador , Uruguay , Paraguay , New Zealand , and Australia , where they are grown extensively as a timber resource, and some species have even become invasive.

Subgenres and sections

Pines are divided into 3 subgenera and several sections and subsections:

• Subgenus Pinus (includes yellow and hard pines)
  • Section Pinus
    • Subsection Pinus
    • Subsection Incertae sedis †
  • Section Pinea ( Mediterranean Pines )
    • Subsection Pineae
    • Pinaster subsection
  • Section Trifoliae ( American Hard Pines )
    • Subsection Leiophyllae
    • Subsection Australes
    • Subsection Contortae
    • Subsection Oocarpae
    • Subsection Ponderosae
• Subgenus Strobus (includes white and downy pines)
  • Section Quinquefoliae or Section Strobus (White pines)
    • Strobi subsection
    • Cembra Subsection
• Subgenus Ducampopinus (includes stone, lacebark and foxtail pines)
  • Parrya Section
    • Subsection Nelsonianae
    • Subsection Krempfianae
    • Subsection Gerardianae
    • Subsection Rzedowskianae
    • Subsection Cembroides
    • Subsection Balfourianae ^[8]

Characteristics

They are evergreen trees , many of large dimensions, rarely shrubs. They are monoecious plants. The branches are arranged in whorls giving the tree a pyramidal appearance, especially when young, in adult trees, wide and depressed. The macroblasts have scale-like leaves without chlorophyll, while the brachyblasts are very short, with a membranous sheath of scales and are finished by two to five linear leaves or needles, with two or more resinous canals each. The male cones develop at the base of the annual shoots.

The strobili have persistent scales, the tectrices being rudimentary and included and the seminiferous ones usually have a protuberance or navel on their external part (apophoses) and mature biennially or triennially. The seeds are winged with the testa more or less lignified. Many species have been cultivated since ancient times for their pine nuts or for ornamental or forestry purposes, which makes it difficult to reestablish their original areas.

The leaves are of three kinds:

• Primordial leaves, solitary and toothed, typical of seedlings.

• Bract-like leaves at the base of the twigs, triangular lanceolate and deciduous.

• Adult, evergreen, needle-like leaves (2 or 3 years old) that emerge in fascicles of 2, 3, 5 or more leaves depending on the species. The cross section is a semicircle in species with 2 leaves and triangular in those with 3 or more.

Uses

Many of the species of this genus produce timber of great economic importance and are employed in a variety of uses, including the construction of bridges and viaducts, buildings, railroad ties, furniture, molding, toys , carving, drawers, paper pulp , etc. When used in contact with the ground it should be preserved with creosote or some other preservative. The variability in the quality of wood, even within the same species, makes economic comparison of properties difficult, but they are generally classified by the species mentioned below as quality types.