A tree’s paradise: Almost the whole of the island was once covered in trees. Worm casts that only occur in oak forest have been found near the summit of Snaefell and tree stumps found in the dew ponds of places like Clagh Ooar (near North Barrule) at 2,000 feet above sea-level show that the ancient forest became island-wide.
Pollen deposits in peat show that the island was almost entirely covered in trees up to 4,000 years ago. Oaks, hazel and alder were predominant. Forest in the lowland bogs may have been largely impenetrable with a mass of undergrowth and fallen trees. Forest on the hills may have been much more open. Deer were present but not wolves or bears.
The clearing of the forests: The denser lowland bog areas were probably the last to be cleared. The deposits of grass pollen in peat start to increase from about 4,000 years ago, showing that grazing was being used for animals. The process of clearing the forest had started. Much of the upland forests may have been cleared by burning with some trees being extracted for firewood, house and boat building.
Over time the process continued until by the 17th century the Isle of Man was left with just scattered remnants of the once extensive forests. Pen and ink drawings from this time show an almost treeless landscape. The introduction of sheep grazing by farmers and landlords in the uplands would have prevented the re-growth of naturally sown trees. There may be some seeds still left in the heather on the uplands that would come back if given the chance.
So what is left? Most of the old trees that you can see today were planted by the Victorians. All the trees in the national glens, around the larger farm houses, the churches, town parks and town streets come from this time. Most of these would probably have been grown from imported seeds. Some saplings might have been imported too.
However, the trees that can be seen clinging to the sides of very steep ravines in the uplands could be native trees of local provenance, a remnant of the ancient forest. They survived the ravages of the forest clearing and intense sheep grazing. Most surviving fragments of ancient woodland are small – some are limited to a grove of just a few trees. But there are a few places like Glen Roy where the old symbiotic balance of an oak/hazel forest still exists. The largest sites are not necessarily the best sites. Some smaller remnants such as Lhen Coan in Groudle Glen and Narradale are very rich in species. The most species-rich sites are probably the oldest.
Many sites show signs of woodland management with coppicing being evident, i.e. the selective taking of branches for firewood, building of houses and boats. The last coppicing would seem to be from about 50 years ago and since then the craft of traditional woodland management has disappeared from the island.
Identification: Ancient Woodland is best identified by its associated plants. Ancient Woodland is not usually marked out by being full of old gnarled trees – it is usually a tumbled mess of new growth amongst older, leaning trees. Oak and hazel trees are the easiest species to spot. On an island with no jays or squirrels, these nut bearing trees will not spread far from their parent tree. So unlike England, self seeded oaks and hazels are not commonly found in hedgerows and new woodland. Where they occur they have either been planted or are the direct descendants of the primeval forests.