Scots pine (Pinus sylvestris): how to identify it

The only native pine in Britain

The Woodland Trust calls Scots pine the only truly native pine in the UK and one of three native conifers. Forest Research considers it native in the north and west of Scotland, in what are known as the Caledonian pinewoods, and calls it the only native conifer of commercial importance. The Woodland Trust gives its natural range as confined to the Highlands, so Scots pines elsewhere in Britain were planted or grew from planted trees.

Trees for Life tells the history. Scots pine spread north from continental Europe after the last Ice Age, about 10,000 years ago, reached its greatest extent about 6,000 years ago, and declined from about 4,000 years ago. The native pinewoods now cover about 17,000 hectares in scattered remnants, just over 1% of an estimated original 1,500,000 hectares. In most of those remnants the largest trees stand about 20 m; exceptional ones reach 27 m. Trees usually live 250 to 300 years in Scotland, and one in a western remnant has been dated at over 520.

The pinewoods carry wildlife found almost nowhere else in Britain: red squirrel, pine marten, capercaillie, crested tit and the Scottish crossbill, a bird endemic to the UK. The Woodland Trust counts about 1,600 species supported by Scots pine, 215 of them found only on it. For the other trees of these woods (birch, rowan, aspen, juniper), see Scottish native trees.

Scots pine vs Corsican, black and lodgepole pine

In British forests, the pine most often confused with Scots pine is Corsican pine, Pinus nigra subsp. laricio, one of the black pines. Forest Research says it was the first pine planted at scale in Britain, from 1919, suits the drier lowlands, grows at Thetford and near Ringwood in the New Forest, and is still the dominant commercial pine, although it is no longer recommended for planting because of red band needle blight. The Austrian pine fact sheet from Virginia Tech describes the black pine of American gardens.

Black pine and lodgepole measurements are Virginia Tech's. The needle color and the upper bark settle most trees: blue-green and orange means Scots pine. For North American look-alikes, the jack pine page covers the short-needled native pine of Canada and the Great Lakes.

Scotch pine in the United States and Canada

In America, Pinus sylvestris goes by Scotch pine. The University of Illinois Extension says it was introduced into the United States by European settlers and calls it the most common Christmas tree, with stiff branches, an open look that leaves room for ornaments, and needles that hold for about four weeks and stay on even when dry. Virginia Tech notes that it is planted widely and may seed into the landscape, grows up to 90 feet, and often has a twisted or poorly formed trunk depending on seed origin.

In North America it is most often confused with other two-needle pines: red pine, Austrian pine and jack pine. The orange upper bark separates it from every one of them, and its needles are shorter than red or Austrian pine needles and longer than jack pine's. The pine identification chart lists the needle counts and lengths of 14 common US pines.

Needles turning yellow: normal shedding or disease

Yellowing needles are a common worry with Scots pine, and in autumn the tree is usually fine. Trees for Life says Scots pine keeps its needles for two to three years; the oldest turn yellow in September or October and fall. Wisconsin Extension gives about three years for Scotch pine and describes natural drop as uniform yellowing of the older, inner needles while the current season's growth stays green.

Spots or bands on current needles, or browning from the needle tips, point elsewhere. Forest Research lists red band needle blight (Dothistroma septosporum) and other needle and shoot diseases among Scots pine's problems, and the pine-tree lappet moth, found in northern Scotland west of Inverness in 2008, as a notifiable pest. A pine near a house or road that is losing needles fast is a job for an arboricultural consultant.

Scots pine is one of the 138 species in Tree Identifier's Collection. A photo of the orange upper trunk or a needle pair gives the app the most to work with, and you can ask the Tree Expert follow-up questions about the result.