It is an evergreen coniferous tree growing up to 25 m in height and 1 m trunk diameter when mature, exceptionally to 35-45 m tall and 1.7 m trunk diameter and on very productive sites (in Estonia, there are some 220 year old trees that are 46 metres tall in the forests of Järvselja). The bark is thick, scaly dark grey-brown on the lower trunk, and thin, flaky and orange on the upper trunk and branches. The habit of the mature tree is distinctive due to its long, bare and straight trunk topped by a rounded or flat-topped mass of foliage. The lifespan is normally 150–300 years, with the oldest recorded specimens (in Sweden) just over 700 years.
The shoots are light brown, with a spirally arranged scale-like pattern. On mature trees the leaves ('needles') are a glaucous blue-green, often darker green to dark yellow-green in winter, 2.5-5 cm long and 1-2 mm broad, produced in fascicles of two with a persistent grey 5–10 mm basal sheath; on vigorous young trees the leaves can be twice as long, and occasionally occur in fascicles of three or four on the tips of strong shoots. Leaf persistence varies from two to four years in warmer climates, and up to nine years in subarctic regions. Seedlings up to one year old bear juvenile leaves; these are single (not in pairs), 2–3 cm long, flattened, with a serrated margin.
The seed cones are red at pollination, then pale brown, globose and 4-8 mm diameter in their first year, expanding to full size in their second year, pointed ovoid-conic, green, then grey-green to yellow-brown at maturity, 3-7.5 cm in length. The cone scales have a flat to pyramidal apophysis, with a small prickle on the umbo. The seeds are blackish, 3–5 mm long with a pale brown 12–20 mm wing; they are released when the cones open in spring 22–24 months after pollination. The pollen cones are yellow, occasionally pink, 8–12 mm long; pollen release is in mid to late spring.
Scots Pine is the only pine native to northern Europe, forming either pure forests or alongside Norway Spruce, Common Juniper, Silver Birch, European Rowan, Eurasian Aspen and other hardwood species. In central and southern Europe, it occurs with numerous additional species, including European Black Pine, Mountain Pine, Macedonian Pine, and Swiss Pine. In the eastern part of its range, it also occurs with Siberian Pine among other trees.
In Great Britain it now occurs naturally only in Scotland, but historical and archaeological records indicate that it also occurred in Wales and England until about 300-400 years ago, becoming extinct there due to over-exploitation; it has been re-introduced in these countries. Similar historical extinction and re-introduction applies to Ireland, Denmark and the Netherlands.
Scots Pine is the national tree of Scotland, and it formed much of the Caledonian Forest which once covered much of the Scottish Highlands. Overcutting for timber demand, fire, overgrazing by sheep and deer, and even deliberate clearance to deter wolves have all been factors in the decline of this once great pine and birch forest. Only comparatively small areas (17,000 ha, only just over 1% of the estimated original 1,500,000 ha) of this ancient forest remain, the main surviving remnants being at Abernethy Forest, Glen Affric, Rothiemurchus Forest, and the Black Wood of Rannoch. Plans are currently in progress to restore at least some areas and work has started at key sites.
Scots Pine is an important tree in forestry. The wood is used for pulp and sawn timber products. A seedling stand can be created by planting, sowing or natural regeneration. Commercial plantation rotations vary between 50-120 years, with longer rotations in northeastern areas where growth is slower. In Finland, Scots Pine was used for making tar in the pre-industrial age. There are still some active tar producers, but mostly the industry has ceased to exist.
The wood is pale brown to red-brown, and used for general construction work. It has a dry density of around 470 kg/m³ (varying with growth conditions), an open porosity of 60%, a fibre saturation point of 0.25 kg/kg and a saturation moisture content of 1.60 kg/kg.
Scots Pine has also been widely planted in New Zealand and much of the colder regions of North America; it is listed as an invasive species in some areas there, including Ontario and Wisconsin. It has been widely used in the United States for the Christmas tree trade, and was one of the most popular Christmas trees from the 1950s through the 1980s. It remains popular for that usage, though it has been eclipsed in popularity, by such species as Fraser Fir, Douglas Fir, and others. Despite its invasiveness in parts of eastern North America, Scots Pine does not often grow well there, partly due to climate and soil differences between its native habitat and that of North America, and partly due to damage by pests and diseases; the tree often grows in a twisted, haphazard manner if not tended to (as they are in the Christmas tree trade).
Other names sometimes used include Riga Pine and Norway Pine, and Mongolian Pine for var. mongolica. "Scotch Pine" is another variant of the common name, used mostly in North America.