The hazel tree is one of the few truly native tree species found in Scotland.
Here in the Borders it’s natural distribution is quite sparse, it can be found on the sea braes, in deep river deans and up some hill cleughs where it will form large, multi-stemmed shrubs.
Often only small populations of ancient plants survive. However, it is now often used in amenity tree planting were it will thrive and provide a valuable habitat for wildlife.
The hazel comes into its own on the west coast of Scotland where it can form extensive natural forests, now classified as the Atlantic Hazel Woods. This ancient forest consisting of almost pure stands of hazel is thought to have existed since just after the last ice age and may date back some 9,500 years.
Most of those ancient forests are found in Argyll and Inverness-shire and on many of the Inner Hebrides. Hazel forests can also be found in western Ireland, Wales and England but are nowhere as extensive and rich as here in Scotland.
The hazel forests can be exceptionally rich in wildlife and are home to some of the richest collections of oceanic mosses, liverworts and lichens found anywhere in the whole of Europe - a Celtic Rainforest.
Left to its own the hazel forms a large multi-stemmed shrub, where there is a succession of new suckering stems arising from the base of the tree and the old stems will eventually die out and fade away. Trunks are only formed where there is grazing which removes the new suckers and the lower twigs and leaves are eaten off.
The natural forests are dense thickets where individual plants perpetuate themselves indefinitely. Around the edges of the forest and in clearings seedling hazels will soon colonise the open spaces if there is only light grazing pressure.
The hazel flowers very early in the year, the male, ‘lambs-tails’ catkins are obvious and dangle down shedding pale yellow pollen into the wind. The female flowers are tiny little inconspicuous buds with 12 crimson styles which catch the pollen. Pollination only takes place between different individual plants as they cannot pollinate themselves.
Lichens are especially rich in the ancient forests and vary from the large leafy types known as lungworts through to the crustose lichens which form smoothish pale-coloured patches on the bare trunks. There are some very special crustose lichens which make a grey-white crust with little black scribble like lines, the script lichens. There are about 20 species of script lichen confined to the Atlantic woodlands and there are some species which are only found here in Scotland and nowhere else in the entire world.
Our hazel woods are rich in wild flowers such as primroses and bluebells. The nuts provide food for mice and birds and a wide variety of insects thrive in their shelter, especially midges - if you venture into an Atlantic Hazel forest on a calm, humid day in summer or autumn be prepared to be driven demented!