Trees
Ancient trees
Even though there is less tree cover in the UK than in many parts of continental Europe, we possess by far the most ancient trees. In fact we are home to 80% of all the ancient trees in northern Europe.
The oldest tree in the British Isles is thought to be the Fortingall Yew in Scotland, which is 5,000 years old. Myths and stories often surround ancient trees and for many years it was thought that the Yew marked the exact centre of Scotland.
In Carmarthen, South Wales, the old stump of a tree known as Merlin's Oak is still kept in the town's civic hall. Even though the tree died in 1856 and the stump was finally dug up in 1978, people still attached a particular importance to it as it was linked to the fortunes of the town through the old saying "When Merlin's Tree shall tumble down, then shall fall (or drown!) Carmarthen Town".
An 800-year-old Oak in Sherwood Forest, known as the Major Oak, is closely associated with the tales of Robin Hood and his Merry Men.
In Ireland the Hawthorn is also known as the Fairy Tree, as it is seen as the special tree of the Leprechauns and Fairies and thus it is seen as very unlucky to cut Hawthorn down.
The age of a tree
The age of a tree is measured by counting the number of growth rings in a cross-section of its trunk. Each growth ring represents one year in the life of the tree. The living part of the tree is actually just underneath the bark and some ancient trees become hollow in the centre of the trunk. Far from killing the tree, this can often make it stronger, as a hollow cylinder (or tree trunk) can be stronger than a solid rod and branches as it weighs less. In the great gales of 1987 the number of hollow trees to be blown down was very small.
The stem - or trunk - of the tree needs to keep expanding to support the leaves and branches, or crown. The height of a tree and the development of a hard outer bark help it to avoid attacks from grazing animals and to use the wind for both pollination and the carrying of large winged seeds.
Tree categories
The British Isles contain a wealth of native species of trees and also a number that have been introduced in fairly recent times, perhaps originally as ornamental species for gardens and parks.
Trees in Britain fall into two main categories, either broadleaves or conifers. Conifers are a distinct group but broadleaves can be related to a number of herbaceous plants. For instance, the Lime tree is a relative of the Hollyhock and the Elm is related to the Nettle plant.
Broadleaved Trees
Broadleaved trees can be subdivided into two groups, firstly wind-pollinated trees and secondly insect-pollinated trees.
Wind-pollinated trees:
This group includes Alder, Ash, Beech, Birch, Elm, Hazel, Hornbeam, Oak, Poplar, Plane, Walnut and some varieties of Willow.
These trees produce flowers before their leaves appear, sometimes in clumps such as the Ash or Elm, or as catkin-type flowers such as the Plane or Walnut. These trees are most common in the temperate zones and make up the majority of British broadleaved trees, becoming rare nearer to the tropics.
Insect-pollinated trees:
This group includes the Box, Elder, Holly, Horse-chestnut, Lime, Maple and some Willows.
These trees have more conspicuous flowers than the wind-pollinated group in order to attract insects. They tend to be either trees that have been introduced from areas further south, or British native trees living at the most northerly point at which they can survive.
Varieties of Woodland
It has been said that until the time of the Norman Conquest "a squirrel could cross England from the Severn to the Wash without once setting foot on the ground".
Primary or Ancient Woodland
An area of land that has been covered in woodland since at least 1600 AD. These woodlands will not have been cleared and many will have been managed by man through coppicing.
Secondary Woodland
An area of land that has been cleared of woodland at some point in its history (for settlement or agricultural reasons) but which has been allowed to regenerate naturally.
Parkland and Urban Trees
Areas which often contain the remains of ancient woodland in the shape of single or grouped mature trees, or sections of ancient hedgerow.
Plantations
An area of land planted with a single or limited range of species of trees. Plantations have mainly been planted this century and the trees in them will be of the same age and usually coniferous. The only native British conifers are Juniper, Scots Pine and Yew, but plantations are often made up of trees introduced to the British Isles by man. Some plantations containing Oak, Beech and Chestnut date from the eighteenth century.
