Caledonian Forest

The Caledonian Forest is the name given to the former (ancient old-growth) temperate rainforest of Scotland. The name comes to us from Pliny the Elder who reveals that 30 years after the Roman invasion of Britain their knowledge of it did not extend beyond the neighbourhood of silva caledonia. He gives no information about where the silva caledonia was, but the known extent of the Roman occupation suggest that it was north of the River Clyde and west of the River Tay.

The Scots pines of the Caledonian Forest are directly descended from the first pines to arrive in Scotland following the Late Glacial; arriving about 7000 BCE. The forest reached its maximum extent about 5000 BCE, after which the Scottish climate became wetter and windier. This changed climate reduced the extent of the forest significantly by 2000 BCE. From that date, human actions (including the grazing effects of sheep and deer) reduced it to its current extent.

Today, that forest exists as 35 remnants, as authenticated by Steven & Carlisle (1959) (or 84 remnants, including later subjective subdivisions of the 35) covering about 180 square kilometres (69 sq mi) or 44,000 acres (18,000 ha). The Scots pines of these remnants are, by definition, directly descended from the first pines to arrive in Scotland following the ice age. These remnants have adapted genetically to different Scottish environments, and as such, are globally unique; their ecological characteristics form an unbroken, 9000 year chain of natural evolution with a distinct variety of soils, vegetation, and animals.

To a great extent the remnants survived on land that was either too steep, too rocky, or too remote to be agriculturally useful. The largest remnants are in Strathspey and Strath Dee on highly acidic, freely drained glacial deposits that are of little value for cultivation and domestic stock. An examination of the earliest maps of Scotland suggests that the extent of the Caledonian Forest remnants has changed little since 1600.

...
Wikipedia