The wild Scots Pines (Pinus sylvestris) of Kielderhead

In the British Isles, Scots Pine (Pinus sylvestris L.) is currently considered to be native only in the Scottish Highlands. Once widespread throughout the archipelago, the species is thought to have declined to extinction outside the Scottish Highlands c.4500 cal BP, and c.1550 cal BP in Ireland. However, there have been discussions about whether some naturally occurring populations may have persisted outside the Highlands into modern times, and potentially may still be alive today. One such population is the enigmatic “Kielderhead Pines” in a remote valley just on the English side of the Scottish border at the heart of the c.60,000 ha Kielder Forest in Northumberland. Debate about the origins of this small population of apparently wild living pines has been ongoing since the 1950s, which has inspired the creation of the “Kielderhead Wildwood” to support its conservation and restoration. We outline the status, significance and the state-of-play in 2023 of our understanding of the origin of these trees, summarising research on the age of the trees, bioclimatic studies, possible botanical evidence of flora and lichen species typical of the Scottish pinewoods and genetics. We conclude that the explanation for the occurrence of the Kielderhead Pines - that they are locally native - remains a possibility, but we recognise and recommend that further research is required. We summarise the conservation efforts that have taken place to secure the pines within a landscape of restored, wild native upland woodland and mires i.e. re-creation of a Northumbrian equivalent of the Caledonian Forest. We also reflect on how the Kielderhead Pines support the case for greater consideration of the restoration of W18 pine woodland vegetation in appropriate locations outside the Scottish Highlands. We conclude by reflecting that one day these few pines, discovered in an isolated valley in Kielder Forest in the 1950s, may be seen as the start of something much bigger in the uplands of northern England, southern Scotland and beyond.