Trees The history of Irish trees begins at the end of the last ice age which was 13,000 years ago. Gradually the plants, trees and animals returned. The first trees were those which could tolerate cold and damp and whose seeds were spread by the wind, such as willow, alder and birch. However, these were eventually replaced by an oak forest which along with other trees covered 90% of the Irish landscape. It is hard to imagine that such a huge forest is what the first people who came to Ireland would have seen 8,000 years ago. Today only 6% of Ireland is forested with mostly introduced coniferous forest. The original deciduous forest now only covers 1% of the landscape.
Oak Quercus robur (Fagaceae) Oaks are deciduous broadleaved trees which can support more species of wildlife that any other Irish tree. The leaves are widest above the middle with 5-7 lobes, dark green above and blue-green beneath. Flowers are borne in catkins: the male is yellow-green and drooping females inconspicuous which in turn produce acorns ripening to a dark brown colour.
Rowan Sorbus aucuparia (Rosaceae) This deciduous tree is conical in shape, spreading with age, has shoots that end in purple buds covered in grey hairs. Pinnate leaves have up to 15 sharp toothed, pointed dark green leaves which are blue-green underneath. The small white flowers have five petals and develop into red berries which are poisonous if eaten raw.
Hawthorn Crataegus monogyna (Rosaceae) The smooth thorny stems of this deciduous tree become cracked with age as the tree spreads. The leaves are oval to diamond-shaped in outline with a broad tapered base and 3-5 sharp toothed lobes, glossy and dark green above with a paler underside. The fragrant white flowers are produced in dense clusters followed by a bright red fruit called a haw containing a single stone.
Scots Pine Pinus sylvestris (Pinaceae) This impressive evergreen tree is conical when young, developing into a rounded spreading head on a tall trunk when mature. The needles are blue-green to blue-grey, male flowers are cylindrical clusters and yellow in colour. The female are upright, red in colour scattered in ones or twos at the tips of young shoots. They take until the second autumn to mature into egg-shaped woody cones which brown when ripe.
Silver Birch Betula pendula (Betulaceae) Silver birch is a medium-sized deciduous tree with a slender trunk and a crown of arched branches with drooping branchlets. The young shoots are rough to the touch with numerous small warts. The glossy and dark leaves are oval to triangular, edged with double teeth, turning yellow in the autumn. The male catkins are drooping while the female are upright. Brown fruit clusters break up when ripe.
Common Holly Ilex aquifolium (Aquifoliaceae) Holly is an evergreen tree often shrub-like in form with glossy, dark green leaves. Leaves range from oval to oblong; the spiny leaves are generally concentrated to the lower younger branches while smooth leaves are on older trees with higher shoots. Flowers grow in clusters with male and female on different trees, the bright red berries only occur on the female trees.
Elder Sambucus nigra (Caprifoliaceae) The deciduous elder is often shrubby with several stems coming from the base with twisted growth and arching branches. The leaves sprout on opposite sides, pinnate with 5-7 oval and pointed leaves. The flat heads of white flowers are in clusters 25cm wide and are followed by edible berries which turn black when ripe.
Common Ash Fraxinus excelsior (Oleaceae) This large deciduous tree has a stout smooth trunk, branches tipped with prominent black buds. The opposite, pinnate leaves have up to 13 dark green leaflets with a slender tapered point at the tip. Tiny purple flowers form in dense clusters, have no petals and form winged fruit which also form in large clusters.
Alder Alnus glutinosa (Betulaceae)