Ireland’s Native Trees
The last survey of native Irish woodlands was carried out over a decade ago. It found about 1,300 native woodland areas, half of which were smaller than six hectares, and only about 40 were larger than 50 hectares, demonstrating the massive level of habitat fragmentation in Ireland today. Still, for a country where only about 2% of our woodland is native we have lots of native tree species; 36 trees and shrubs in total. The top ten native Irish trees in order of abundance in our native woodlands are presented in this article.
Image source: Richard Gordon. The ancient alluvial woodland of The Gearagh in spring.10. Hawthorn (Crataegus monogyna)
Image source: futureforests.ie. Hawthorn (Crataegus monogyna)
The fleshy red haws of the hawthorn tree appear in late summer and ripen for the winter, providing a valuable food source for our winter birds. It gets part of its scientific name from having just one stone in its fruit as opposed to sister species, midland hawthorn (C. laevigata), which has two. It is common in hedgerows and is found at woodland edges. It is in the Rosaceae family, which it shares with the Sorbus genus, the most common of which is the rowan (Sorbus aucuparia) or mountain ash, which also has lots of red berries in autumn.
9. Pedunculate oak (Quercus robur)
Image source: futureforests.ie. Pedunculate oak (Quercus robur).
The Gaelic name for this tree species, which makes up about 5% of our native woodlands, is ‘Dair Ghallda’, as opposed to the other oak species, ‘Dair Ghaelach’ (see no. 7). It gets its Irish name from its association with the arrival of the British into the country. Its common name is derived from the stalk or ‘peduncle’ attached to the cup on which the acorn develops. It prefers more alkaline soils in the lowlands and is usually smaller than the other oak species.
8. Holly (Ilex aquifolium)
Image source: futureforests.ie. Holly (Ilex aquifolium).
It forms one of the minor woodland types along with yew, that of yew-holly woodland. It forms the shrub layer in native woodlands, such as the oak forest in Glengarriff, Co. Cork. Although it has spines, it is palatable to cattle, goats and other mammals.
7. Sessile oak (Quercus patraea)
Image source: futureforests.ie. Sessile oak (Quercus patraea).
This is the national tree of Ireland. It grows on more acidic soils and in rocky places such as hillsides. It comprises almost 7% of native woodlands. Both oak species are in the Fagaceae family, which they share with beech (Fagus sylvatica). Although it makes up 3% of Irish woodlands, beech is not considered a native tree, having been introduced into Irish demesnes in the late 1700s. Sessile oak forms one of the four major woodland types, that of oak-woodrush woodland. Hybridisation between the two oak species occurs and about 1% of our native woodland is comprised of the hybrid, Quercus x rosacea.
6. Alder (Alnus glutinosa)
Image source: woodlandtrust.org.uk. Alder (Alnus glutinosa).
Alder forms carrs around wetland areas, as it is adapted to waterlogged soils. Its fruits appear as cones which start out green, then turn a purplish colour, and finally black. Over 7% of our native woods are composed of alder. It forms one of the four major woodland types, that of alder-meadowsweet woodland.
5. Grey willow (Salix cinerea)
Image source: futureforests.ie. Grey willow (Salix cinerea).
It is one of five native willow species, the others being bay willow (S. pentandra), purple willow (S. purpurea), goat willow (S. caprea) and eared willow (S. aurita). It forms one of the minor woodland types along with nettle, and is common in riparian areas.
4. Scots pine (Pinus sylvestris)
Image source: futureforests.ie. Scots pine (Pinus sylvestris).
It is one of three native conifers, the others being yew (Taxus baccata) and juniper (Juniperus communis). It was believed to have been extirpated during the last Ice Age, but pollen was discovered recently in the Burren from pre-glacial times and seedlings from this stock have recently been replanted.
3. Hazel (Corylus avellana)
Image source: futureforests.ie. Hazel (Corylus avellana).
In third place for most widespread native trees in Ireland, is hazel. In the Burren, Co. Clare, one of the few strongholds for the tree, management practices towards hazel vary according to its location. It is the dominant tree along with ash where it forms lowland scrub on the rocky limestone flats. However, on the upland parts of the Burren hazel spreads in the absence of grazing sheep and cattle and land-owners are now encouraged to keep its growth in check. This is done in order to maintain the balance of the Burren’s unique floral species because if too much hazel encroaches, floral abundance would be impacted.
2. Ash (Fraxinus excelsior)
Image source: woodlandtrust.org.uk. Ash (Fraxinus excelsior).
The next most widespread tree in Ireland is the mighty ash, which makes up about 19% of our native tree species. It is currently being badly affected by the Hymenoscyphus fraxineus fungus, causing ash dieback disease. It is the most common tree growing in hedgerows where it was planted in the 17th century when field boundaries were being created for agriculture. It comprises the ash-ivy woodland type, which occurs on moderately acidic and free-draining soils.
1. Birch (Betula pubescens)
Image source: futureforests.ie. Birch (Betula pubescens).
Comprising over 20% of all native trees, the most widespread native tree in Ireland is downy birch. This birch species has downy twigs as opposed to the glossier young twigs of its sister species, silver birch (Betula pendula), whose branches hang like pendulums, but which makes up only 0.03% of native woodlands. Many of our upland areas, if left to regenerate, would see montane birch forests become established in mosaic with blanket mire and heaths. It forms one of the four major woodland types, that of birch-purple moor grass woodland.
Some of the other native Irish tree species are:
- Elder (Sambucus nigra)
- Elm (Ulmus glabra)
- Buckthorn (Rhamnus cathartica)
- Crab apple (Malus sylvestris)
- Blackthorn (Prunus spinosa)
- Wild cherry (Prunus avium)
- Aspen (Populus tremula)
- Black poplar (Populus nigra)
- Spindle (Euonymous europaeus)
- Guelder rose (Viburnum opulus)
Endangered native Irish tree species:
- Bird cherry (Prunus padus); it’s on the UN Red List.
- English, Irish and Rock Whitebeams: Sorbus anglica, S. hibernica and S. rupicola.
Non-native trees:
- 75% of woodland is conifer species, Sitka spruce (Picea sitchensis) and Norway spruce (Picea abies).
- 2% is Sycamore (Acer pseudoplatanus).
- 0.13% is Larch (Larix sp).
- 0.06% is Cherry laurel (Prunus laurocerasus).
Some of our forests are Priority habitats under the European Union Habitats Directive and are protected as Special Areas of Conservation. The four habitats are: ancient alluvial woodland (The Gearagh, Co. Cork), ancient yew (Killarney National Park), bog woodland (Wicklow Mountains National Park), and limestone woodland (The Burren, Co. Clare).
By Stephen Mulkearn MSc Biodiversity & Conservation
Stephen Mulkearn
MSc Biodiversity & Conservation
