Pinus pinaster

Pinus pinaster, called the maritime pine, is a medium-sized tree native to the southern Atlantic coast of Europe and parts of the western Mediterranean. It grows quickly and belongs to the hard pines, bearing long needles and large cones that hold medium-sized seeds equipped with large wings.

The tree typically reaches 20–35 meters tall, though it can grow up to 41 meters, with a trunk diameter of up to 1.2 meters (occasionally 1.9 meters). Its bark is orange-red, thick, and deeply cracked near the base, becoming thinner higher up. The needles grow in pairs, are 10–25 cm long and very stout (about 2 mm wide), and range from bluish-green to yellowish-green. Among European pines, this species has the longest and most robust needles. The cones are conical, 8–22 cm long and 4–6 cm wide at the base when closed. They start green and turn glossy red-brown after two years, then open slowly over several years—or quickly when heated by a wildfire—to release seeds. When open, the cones measure 8–12 cm across. The seeds are 8–10 mm long, shiny black on top and dull gray-brown underneath, with a wing 20–25 mm long that helps them disperse by wind.

Maritime pine is closely related to Turkish pine, Canary Island pine, and Aleppo pine, sharing many traits with them. It shows little variation across its range, though three subspecies are recognized by some sources: *Pinus pinaster* subsp. *pinaster* in Atlantic Europe, subsp. *escarena* in Mediterranean Europe, and subsp. *renoui* in the Atlas Mountains of northwest Africa.

Its native range spans the western Mediterranean Basin and the southern Atlantic coast of Europe, from central Portugal and northern Spain through southern and western France, east to western Italy and Croatia, and south to northern Tunisia, Algeria, and Morocco. It prefers a Mediterranean climate with cool, wet winters and hot, dry summers. North of its native range, it has become naturalized—and locally invasive—in southern England. It grows mostly from sea level up to 600 meters, but reaches 2,000 meters in southern Morocco. Its current fragmented distribution results from mountain ranges isolating populations and from human activity.

The species favors acidic soils with medium to dense vegetation, but can also grow in basic, sandy, or poor soils where few commercial trees thrive. It is a diagnostic species of the vegetation class *Pinetea halepensis*. Factors affecting its spread include seed dispersal, habitat loss, and fecundity.

Larvae of the moth *Dioryctria sylvestrella* feed on this pine, boring into it and causing heavy resin flow that weakens the tree and opens the door to fungi and other pathogens. In Portugal, the fungus *Pestalotiopsis pini* has emerged as a pathogen on both stone pine and maritime pine, causing shoot blight and stem necrosis on needles, shoots, and trunks.

Maritime pine is a well-known invasive species in South Africa, where it has been spreading for about 150 years after being introduced in the late 1600s. It was found in the Cape Peninsula by 1772, widely planted by 1780, and commercially grown for timber by the early 1800s. It invades large areas, especially fynbos vegetation—a fire-prone shrubland in the southern and southwestern Cape—and is most abundant near watercourses.

The invasion has reduced native biodiversity in South Africa. In the Cape Peninsula, invasive species can decrease native plant diversity by 50–86%. Shrublands suffer the largest decline in species richness when invaded. Compared to grasses, trees, annual herbs, and creepers have a stronger negative effect on species richness. South Africa also shows the greatest species richness decline from invasive species of any country studied, partly because few local insects or diseases limit the pine’s population. Additionally, where maritime pine invades grasslands or shrublands, it can significantly lower stream water levels, since it is an evergreen tree that takes up large amounts of water.