Plant 161

Pinus sylvestris L. (Pinaceae)


Scots pine

Scots pine is one of the world's most widely distributed conifers, and one of only three native British gymnosperms. Its native distribution extends from north of the Arctic Circle to Turkey in the south and from northern Spain and Scotland in the west through Eurasia to the Russian Far East.

Over the last century, pine trunks and pollen grains have been used as time machines to understand millennia of global climatic patterns. The growth of temperate trees responds to climate in the patterns of annual growth rings they produce in their trunks. Rings form in wood because of growth changes during the year; the inner part of a ring forms when growth is comparatively rapid (early wood), while the outer part of the ring forms when growth is comparatively slow (late wood). Furthermore, trees produce wide growth rings in favourable growth years but narrow growth rings in poor growth years. Consequently, growth rings give information both about the age of particular trees and the growing conditions they experienced in particular years. Pines have proved particularly valuable for tree ring analysis because of their longevity, their commonness and their long history of human use. By piecing together tree-ring signatures from pines in a temporal jigsaw, tree-ring chronologies covering the last twelve millennia have been constructed. Such chronologies have revealed patterns of climate change variation.

Scots pine has distinctive, buoyant, wind-borne pollen grains which are extremely resistant to decay; they can be readily identified even after being buried for thousands of years. The pollen grains in cores of lake sediment are ecological samples though time, creating a picture of how plant communities have changed through time. Pollen cores have shown how the distribution of pine forests has varied across the British Isles since the end of the last glaciation, approximately 10,000 years ago.

Combining data obtained from pollen records and from DNA analyses, a picture of the recolonisation of Britain by Scots pine has emerged. 8,000 to 9,000 years ago pines colonised Britain from the continent, and reached their maximum extent about 6,000 years ago. Today, there is no native Scots pine in England, and only a few, scattered Scottish populations. Past exploitation, which selectively removed the tall, erect trees, has meant that the surviving populations are dominated by squat trees with broad crowns and twisted branches. Besides timber and pulp, in times past, pines were used for making tar and turpentine.

Further reading

Farjon A 2016. Conifers of the world. Resources for Conifer Research.

Hemery G and Simblet S 2014. The new Sylva. A discourse of forest & orchard trees for the twenty-first century. Bloomsbury.

Loader NJ et al. 2011. Reconstructing Holocene climate from tree rings: the potential for a long chronology from the Scottish Highlands. The Holocene 22: 3-11.

Stephen Harris