The Woods of Caledon
The pine woodlands of the Scottish Highlands, the so called Woods of Caledon or the Caledonian Forest, as a climax forest ecosystem must be considered as part of the Eurasian formation of Northern Coniferous Forest, or Boreal Forest. In Scandinavia the dominant tree of this formation, as far north as Lapland is the Norway spruce, Picea abies. Further north in Norwegian and Finnish Lapland this species is replaced by forests of pine, Pinus sylvestris, and then by birch, Betula tortuosa. The spruce, however, did not re-enter the British Isles in the post-glacial period. In the early post-glacial forests of birch and pine spread across the country and invaded the uplands and highlands. In the succeeding Climatic Optimum these trees were replaced in the south by a forest of oak, elm, and lime, which in turn extended northwards into the valleys and straths of upland Britain. The traditional picture that emerges of the potential natural woodlands of the Highlands is one of oak woodlands flooring the valleys and glens up to perhaps 150m to200m. Here on the mountain slopes, particularly in the east and central Highlands, they gave way to forests of pine which reached altitudes of over 700m, wherever soils and exposure permitted (the highest natural pines today are at
603m on Creag Fhiaclach in Glen Feshie in the Cairngorms). In the west pine woods were also extensive, but restricted to more moderate slopes and confined to lower altitudes than in the east. Higher still the pine gave way to woods or scrub of birch and/or juniper, while latitudinally, in the north and northwest Highlands pinewoods were replaced by native birch woodlands. In other words oak, pine, and birch were zoned altitudinally and latitudinally.