Oak / Ash / Hazel woodlands, following the pioneering birch and willow scrub, are our oldest native woodlands which were the first to colonise following the last Ice Age (10,000 years ago) - oak being the 'climax' vegetation relegating other trees to understorey, wet or boggy areas, river banks and woodland edges. Hundreds of plants, animals, birds and insects have evolved with these woodlands - oak and ash leaves open relatively late allowing more sunlight through, so these are the richest of all woodlands for biodiversity - the variety of living things. As many as 500 species of flora and fauna are closely associated with the oak.
Sadly, little of the ancient oak forests remain but we have a few important sites in Clare. We have two species of native oak - 'sessile' (Quercus petraea) and 'pedunculate' (Quercus robur). Sessile arrived first - it prefers humidity and doesn't mind poor soils, so has readily taken to our upland regions. Pedunculate (acorns on a stalk known as a 'peduncle') followed keeping to the better soils of river valleys. There are pedunculate oaks in Cahiracon Wood near Killadysert, by the shores of Castle Lake near Sixmilebridge, Lough Graney woods near Feakle and Cloonamirran Wood near Mountshannon. Fine examples of sessile oak several hundred years old can be found at Raheen Wood, Tuamgraney.
'Leafy branches were all around me, shooting grasses and growths abounded; There were green plants climbing and worts and weeds that would gladden your mind and clear your head...........In a nest in a ditch beside the trees...... [Brian Merriman - The Midnight Court (Seamus Heaney's version)]
A Wealth of colour and activity
Several other native trees and shrubs are found in amongst the oak / ash / hazel including wych elm, wild cherry, crab apple, guelder rose, dog rose, hawthorn, blackthorn, elder, holly and ivy. Springtime is when many of the wildflowers bloom – lesser celandine, wood sorrel, wood anemone, bluebells, early purple orchid, ramsons. Butterflies become active seeking nectar – wood white, speckled wood, brimstone, peacock, small copper, common blue, meadow brown. Resident birds eat insects, slugs, snails for part of the year and enjoy seeds and nuts through the winter – tits, chaffinch, siskin, redpoll, goldcrest, tree-creeper are wide spread and predators include sparrowhawk and long-eared owl. Summer visitors include chiffchaff, willow warbler and grasshopper warbler. Mammals include wood mouse, red squirrel, fox, badger, pine marten, stoat and fallow deer.
People have been using native timber for at least the past 7,200 years
Because it is such a strong and hard-wearing timber, mankind has decimated the oak forests that once covered this country – for construction, barrels, ships, and what is left is now confined to fenced off areas between farmlands. Remnants of wooden posts and dug-out canoes found in bogs have been dated showing that people have been using native timber in their day-to-day lives for at least the past 7,200 years. Oak would naturally spread outwards thanks to squirrels and jays taking acorns away from the woodland edge, but this cannot succeed where the surroundings are agricultural land. This means that to ‘preserve’ a woodland is, in the long term, impossible because eventually introduced species such as beech and sycamore will come in and take over. What we can do is ‘conserve’ by careful management – removing invasives and allowing the native trees to regenerate. The ancient traditional practice of coppicing (regular cutting of stems every few years causing vigourous new shoots to re-grow) also prolongs the life of the trees. Wildlife also needs the hedgerows and trees along river banks for cover to travel between woodlands.
Ash and hazel
Ash grows happily almost anywhere in Ireland, but especially on alkaline soils and along streams and at the base of slopes. Along with hazel it grows as a natural part of the oak wood understorey. Some parts of the Burren with limited soil have patches of ash / hazel woodland e.g. in the Caher valley near Fanore and the Glen of Clab. Ash is highly valued for its springiness as in hurleys and tool handles, as well as being used for furniture and good firewood. Hazel was the traditional timber for ‘wattle and daub’ walls and woven screens because it is easy to split and weave. It also is used for furniture and firewood.
........when pale light shining on water and fallen among leaves, and winds blowing from flowers, and whirr of feathers and the green quiet, have uplifted the heart ......... [W.B.Yeats]
Woodland ecology – different plants for different conditions
The trees and shrubs of a woodland reflect the soil and climatic conditions. Upland strongly acidic soils will support sessile oak, birch and rowan with little or no hazel. More hazel is found in neutral or alkaline soils along with ash and pedunculate oak. Hawthorn, blackthorn and elder prefer alkaline, clay soils; holly and furze prefer acid, sandy soils whilst alder and willow prefer wet conditions.
Study of the ground vegetation also helps provide a picture of the ecology of the woodland and is useful for classifying woodland types. Ling, bell-heather, bracken and foxglove tend to be found more in dry, acidic soils whilst marsh marigold, yellow flag-iris and mint prefer wet, alkaline conditions. Rushes, cross-leaved heath, purple moor grass and sphagnum mosses prefer wet, acidic conditions whilst primrose and sanicle prefer dry / alkaline. Honeysuckle, wood sorrel and common dog violet prefer dry, neutral soils whilst marsh thistle and creeping buttercup like wet / neutral. Often a variety of conditions exist within a woodland area giving rise to a variety of habitats and a rich bio-diversity. Over 80 species of wildflower have been recorded in Raheen Wood, Tuamgraney and in Dromore Wood. Flowers such as wood anemone, bluebell, yellow pimpernel, sanicle and spindle are considered probable indicators of ancient woodlands that have existed for several hundred years or more.
The tree canopy and the amazing world below ground
The woodland eco-system extends way beyond the actual trees and ground level. The canopy is home to mosses, lichens, ferns and vast numbers of insects which in turn attract many birds. Below ground is another rich world of insects, bacteria and a network of microscopic fungi (mycorrhiza) – these all exchange energy through the tree roots, giving nitrogen and trace elements in return for sugars that the tree has made in the process of photosynthesis using energy from sunlight and carbon dioxide from the air. Eventually the falling leaves and dead trees return their stock of nutrients to the soil surface – a perfect compost for seeds to germinate and grow into new trees. As George Bernard Shaw said – ‘No man manages his affairs as well as a tree does’.
