Stone pine in Brissago, on Lake Maggiore, Switzerland
The stone pine is aconiferousevergreen tree that can exceed 25 metres (80 feet) in height, but 12–20 m (40–65 ft) is more typical. In youth, it is a bushy globe, in mid-age an umbrella canopy on a thick trunk, and, in maturity, a broad and flat crown over 8 m (26 ft) in width.[2] Thebark is thick, red-brown and deeply fissured into broad vertical plates.
The flexible mid-green leaves are needle-like, in bundles of two, and are 10–20 cm (4–8 in) long (exceptionally up to 30 cm or 12 in). Young trees up to 5–10 years old bear juvenile leaves, which are very different, single (not paired), 2–4 cm (3⁄4–1+1⁄2 in) long, glaucous blue-green; the adult leaves appear mixed with juvenile leaves from the fourth or fifth year on, replacing it fully by around the tenth year. Juvenile leaves are also produced in regrowth following injury, such as a broken shoot, on older trees.
Cone
The cones are broad, ovoid, 8–15 cm (3–6 in) long, and take 36 months to mature, longer than any other pine. The seeds (pine nuts,piñones,pinhões,pinoli, orpignons) are large,2 cm (3⁄4 in) long, and pale brown with a powdery black coating that rubs off easily, and have a rudimentary4–8 mm (5⁄32–5⁄16 in) wing that falls off very easily. The wing is ineffective for wind dispersal, and the seeds are animal-dispersed, originally mainly by theIberian magpie, but in recent history largely by humans.
ThePinus pinea is a characteristic, yet controversial, species throughout theMediterranean basin. Its definitivenative range is highly debated. Strong evidence suggests its origin is in the Western Mediterranean, particularly theIberian Peninsula (Portugal andSpain), where the most extensive natural stands are found, and where it reaches its highest altitudes. The presence ofPaleolithic andPleistocene sites containing the remains ofPinus pinea on the South Iberian Peninsula provides strong evidence that the species was once part of the natural forest ecosystem in that region. Furthermore, the presence of pollen dating between 18-22 thousand years ago (end of Pleistocene) in Southern France supports the hypothesis of its native status there.[3]
The species has been intensively cultivated for its valuable edible nuts and wood since at least the 4th century B.C. and earlier. This long history of human intervention means that while it is found today across coastal areas from Portugal to Lebanon and theBlack Sea, it is often impossible to distinguish between truly native stands and those that are now naturalized from ancient artificial plantings.[4]
The prehistoric range ofPinus pinea included North Africa in the Sahara Desert andMaghreb regions duringa more humid climate period, in present-day Morocco, Algeria, Tunisia, and Libya.[citation needed]
In Greece, although the species is not widely distributed,[5] an extensive stone pine forest exists in westernPeloponnese at Strofylia[6] on the peninsula separating the Kalogria Lagoon from theMediterranean Sea. This coastal forest is at least 13 kilometres (8 miles) long, with dense and tall stands ofPinus pinea mixed withPinus halepensis.[7] Currently,P. halepensis is outcompeting stone pines in many locations of the forest.[8] Another location in Greece is atKoukounaries on the northern Aegean island ofSkiathos at the southwest corner of the island. This is a half-mile-long dense stand of stone and Aleppo pines that lies between a lagoon and theAegean Sea.[9]
In Western Asia, theEastern Mediterranean conifer-sclerophyllous-broadleaf forests ecoregion in Turkey; and the Southern Anatolian montane conifer and deciduous forests ecoregion in Turkey, Syria, Lebanon, Israel and in the Palestinian Territories.
In theWestern Cape Province, the pines were according to legend planted by theFrench Huguenot refugees who settled at the Cape of Good Hope during the late 17th century and who brought the seeds with them from France. The tree is known in theAfrikaans language askroonden.
The introducedWestern conifer seed bug (Leptoglossus occidentalis) was accidentally imported with timber to northern Italy in the late 1990s from the western US, and has spread across Europe as an invasive pest species since then. It feeds on the sap of developing conifer cones throughout its life, and its sap-sucking causes the developing seeds to wither and misdevelop. It has destroyed most of the pine nut seeds in Italy, threateningP. pinea in itsnative habitats there.[11]
Pestalotiopsis pini (a genus ofascomycete fungi), was found as an emerging pathogen onPinus pinea in Portugal. Evidence of shoot blight and stem necrosis were found in stone pine orchards and urban areas in 2020. The edible pine nut production has been decreasing in the affected area due to several factors, including pests and diseases. The fungus was found on needles, shoots and trunks ofP. pinea and also onP. pinaster.Pestalotiopsis fungal species could represent a threat to the health of pine forests in the Mediterranean basin.[12]
Pinus pinea has been cultivated extensively for at least 6,000 years for its edible pine nuts, which have been trade items since early historic times. The tree has been cultivated throughout theMediterranean region for so long that it hasnaturalized, and is often considered native beyond its natural range.
The tree is among the current symbols ofRome.[13] It was first planted in Rome during theRoman Republic, where many historicRoman roads, such as theVia Appia, were (and still are) embellished with lines of stone pines. Stone pines were planted on the hills of theBosphorusstrait inIstanbul forornamental purposes during theOttoman period. In Italy, the stone pine has been an aesthetic landscape element since theItalian Renaissance garden period. In the 1700s,P. pinea began being introduced as an ornamental tree to otherMediterranean climate regions of the world, and is now often found in gardens and parks in South Africa, California, and Australia. It has naturalized beyond cities in South Africa to the extent that it is listed as aninvasive species there. It is also planted in western Europe up to southern Scotland, and on the East Coast of the United States up to New Jersey.
Small specimens are used forbonsai, and also grown in large pots and planters. The year-old seedlings are seasonally available as table-topChristmas trees 20–30 cm (8–12 in) tall.