A tree varying in height from 60 to over 100 ft, usually of pyramidal form, especially when young; young shoots clothed with a thick coat of brownish down. Leaves in fives, very densely packed on the shoots, persisting three to five years according to vigour; pointing forward, fragrant in summer, 11⁄2 to 41⁄2 in. long, rich green; triangular, with three to five lines of stomata on two faces; margins toothed except near the point; leaf-sheaths 3⁄4 to 7⁄8 in. long, soon falling away. Cones egg-shaped, 2 to 3 in. long, scarcely as wide; the scales do not expand, and the seeds fall with the cones and are either released by birds or animals or by the decay of the scales.
Native of the Alps, from France to Lower Austria, and of the Tatras and Carpathians, rarely descending below 5,000 ft. In the Alps it occurs in the inner ranges, where it is often associated with the common larch and forms with it the highest limit of tree growth. Visitors to the high valleys of the Mont Blanc area, the Engadine, the Valais, and the inner Tyrol will have noted picturesque old veterans that have braved the storms, doubtless for hundreds of years.
The Arolla pine was in cultivation in Britain as early as 1746, when the Duke of Argyll had it at Whitton near Hounslow. In 1903 there was still a tree there which must have been planted in the Duke’s lifetime, i.e., before 1761. It makes a very handsome small tree, pyramidal, densely branched and very leafy, especially from 8 to 20 ft high. It does not appear to be long-lived nor produce cones freely in southern England, although there are trees between 60 and 70 ft. The oldest is a leaning tree at Dropmore, Bucks, pl. 1795, measuring 65 × 73⁄4 ft (1970). Others in the south are: Lythe Hill, Haslemere, Surrey, 70 × 6 ft (1970); Leonardslee, Sussex, 60 × 43⁄4 ft (1960); Waddesdon, Bucks, 62 × 71⁄2 ft (1973). P. cembra grows best, however, in the cooler and rainier parts of the country. Examples in these areas are: Powis Castle, Montgom., 71 × 8 ft and 60 × 9 ft (1970); Taymouth Castle, Perths., 90 × 11 ft (1970); Dawyck, Peebl., pl. 1840, 58 × 81⁄2 ft (1974); Murthly Castle, Perths., 80 × 8 ft (1970).
P. sibirica Du Tour P. cembra var. sibirica Loud. – This Russian species is very closely allied to P. cembra, and is by some botanists included in it without differentiation. The main differences are that in the Siberian tree the leaves are longer, the cones longer and relatively narrower, with thinner scales. Its distribution in Russia is vast, from about 55° E. to an eastern limit around 1250 E. Its name in Russian is kedr – a word of the same parentage as ancient Greek kedros and Latin cedrus. In English translations of Russian works this is usually misleadingly rendered as ‘cedar’.
P. pumila (Pall.) Reg. P. cembra var. pumila Pall. Dwarf Siberian Pine. – Botanically this species is near to P. cembra, although of different aspect. It is a dwarf, mostly prostrate shrub rarely over 10 ft high in the wild, the shoots downy, the leaves usually 11⁄2 to 23⁄4 in. long, hence shorter than in P. cembra, and are usually less toothed or entire (finely toothed almost throughout in P. cembra). Male flowers deep red. Cones and seeds smaller than in P. cembra, the former about 11⁄2 in. long. It is a native of the colder parts of N.E. Asia, including Japan, often forming extensive thickets above the tree-line or in other exposed places. It was in cultivation early last century, but appears to have been lost sight of until the beginning of this century, when Admiral Clinton Baker collected plants in Japan and sent them to the Bayfordbury collection.
In cultivation P. pumila varies in size and habit, but is usually under 4 ft in height. It associates well with the heaths.
Selections are: ‘Dwarf Blue’, with glaucous leaves and of spreading habit; and
P. × hakkodensis Makino – A natural hybrid between P. pumila and P. parviflora, occurring in the northern part of the main island of Japan, and originally described from Mt Hakkoda. Near to P. pumila, but with longer, thicker, twisted needles (Krüssmann, Handb. der Nadelgehölze (1972), plate 97). It is said to be of promise as an ornamental plant.