On a hillside in the western Highlands, a retired biology graduate named Sheena Macaulay crouches in the undergrowth — not searching for insects this time, but for seeds. A former IT manager at Scottish Power's Cruachan hydroelectric station near Oban, Macaulay is one of roughly 100 volunteers who have collectively spent tens of thousands of hours combing remote woods and exposed coastal slopes to collect the raw material for a quiet ecological revolution. Between them, they have gathered eleven million seeds by hand, a figure that has since translated into nearly eight million native trees now growing in Scottish soil. The trees they are restoring belong to a habitat known as Atlantic rainforest — a rare temperate ecosystem shaped by the UK's moist coastal climate and one that once stretched across much of western Scotland.

The latest surveys estimate that only 30,000 hectares of original Atlantic rainforest remain, reduced by centuries of grazing, felling and agricultural clearance. What survives is now the focus of multimillion-pound restoration projects, and the volunteers are central to their success. Using detailed maps compiled by NatureScot and Scottish Forestry, they seek out specimens of hazel, sessile oak, dwarf birch, juniper, wych elm, yew and elder — species whose ancestry in Scotland stretches back to the period immediately after the last ice age. The genetic dimension of this work is considered critical.

Ecologists argue that trees which have grown in specific microclimates along Scotland's Atlantic coast have inherited traits that allow them to tolerate the local soil chemistry, rainfall patterns and temperature swings — resilience that a commercially sourced, non-native sapling could not reliably replicate, particularly as the climate continues to shift.