Quercus robur
Common names: English oak, pedunculate oak
Irish name: Dair ghallda
Latin name: Quercus robur
Family: Fagaceae
Origin: Native
Tree type: Deciduous broadleaf tree
How it looks
Shape, bark, twigs
The English oak can grow up to 40m in height, forming a broad and spreading crown with sturdy branches beneath. Its bark is greyish-brown in colour. When it is young, it is smooth, but with age, it becomes more rugged, developing vertical ridges that allow rainwater to reach the ground.
Buds
The Pedunculate Oak buds are 3-8 mm long, alternate along the stem, and are found in clusters at the stem end. Unlike the sessile oak buds, the Pedunculate oak buds have less than 20 scales and are not hairy.
Leaves
The leaves of the Pedunculate Oak are around 10cm long with 4–5 deep lobes with smooth edges. They have no, or a very short, leaf stalk and two ‘earlobes’ at their base. Their leaves appear in April or May, two weeks earlier than the Sessile Oak.
Flowers
The pedunculate oak has both male and female flowers on the same branch. The male flower produces the pollen, which is transported by the wind to pollinate female flowers. Male flowers are bright green catkins, whereas female flowers are small clusters of modified leaves that look like red buds near each twig's tip on the end of long stalks. Leaves get in the way of the pollen being blown away, so the flowers appear before the leaves are fully grown in early spring.
Fruits
In September, after pollination, female flowers develop into acorns. The Pedunculate oak produces acorns on long stalks, also known as peduncles, hence the name. The acorns are 2–2.5cm long and grow in ‘cups’ at the base of the acorn. Young acorns are green, which, as they mature, will turn brown and fall from the cup to the ground. Each acorn contains a single seed encased in a tough outer shell.
Similar species
Where to find it
The pedunculate oak is the less common of the two oaks native to Ireland. It is commonly found in Ireland's midlands, like Charleville in Co Offaly. The pedunculate oak is generally associated with heavy lowland soils, being located close to rivers on damp, moist land that can withstand wet soil in winter.
Cultural importance
History | Myth | Literature
History
According to a ninth-century law text, the Oak, or Dair as it is named in Irish, was considered one of the seven ‘Nobles of the Wood’ in early Irish society (c. 400-1000 AD). It was deemed exceptionally valuable in that its acorns provided an important food source for the fattening of pigs and its timber provided sturdy material for fencing and housebuilding. The bark of the oak was also used in early Ireland to tan leather.
This esteem for oak stretches back into prehistory. The discovery of a large dugout canoe in a bog in Addergoole, Co. Galway reveals that oak was used for water transport during the Bronze Age (c. 2500-800). Likewise, the findings from archaeological excavations in Corlea, Co. Longford demonstrate that oak was used in the Iron Age (c. 800 BC -400 AD) for the construction of large wooden trackways for traversing the bog. These same excavations also produced a number of domestic and agricultural artefacts made of oak, including ard ploughs, troughs, carts and mallets.
Oak was so significant in Ireland during the early Medieval period that one of the letters of the early Irish Ogham alphabet was named after it, with its Irish name, Dair, representing the letter ‘D’:
Due to the considerable value of trees in early Ireland, if someone damaged or destroyed another person’s tree they would be expected to pay a penalty. The penalty for damaging one of the Nobles of the Wood, including oak, was particularly severe. Fergus Kelly tells us that:
For any offence against one of the lords of the wood, the culprit must pay a penalty-fine (díre) equivalent to two milch cows and a three-year-old heifer. In addition, if the injury he has inflicted is merely branch-cutting, he must pay compensation (aithgin) of a yearling heifer; if it is fork-cutting, a two-year-old heifer is due, and if base-cutting, a milch C (Kelly 1999, 41)
In Viking Dublin, oak was highly valued and used extensively for shipbuilding - oak timbers recovered from the wreck of a Viking long ship in Roskilde Fjord, Denmark were revealed to have come from the Dublin area where the vessel was originally constructed. In Viking Waterford, oak was used for the construction of houses.
During the late Medieval period (c. 1100-1600 AD), oak was widely used in the construction of Anglo-Norman buildings. This period also saw the export of timber from Ireland. As Paul McMahon relates, Irish oak was used to rebuild Canterbury Cathedral around 1175 AD, to construct Salisbury Cathedral circa 1224 AD and in the construction of the Norman castles at Marborough, Winchester and Haverford.
In the sixteenth and seventeenth centuries, oak from Ireland was a major source of charcoal for iron-smelting, and thus foundational to the English iron industry throughout this period. Oak was also the primary material used in building ships and houses until the middle of the 19th century, when steel became readily available. Indeed, in the seventeenth century, Irish oak was used in the construction of towns such as Londonderry and the reconstruction of London, England after the Great Fire of London.
In other parts of the world, acorns have been foraged and used for thousands of years. They were once a staple in people's diets throughout Europe, being ground to make bread flour. The use of oak bark to tan leather was also practiced in other parts of Europe as far back as the Roman period.
While the great native oak woodlands of the island of Ireland have been all but cleared, their memory lives on in Irish place names, such as Adare, which means ‘The ford of the oak tree’, and Derry (or Londonderry) which comes from Daire or Doire, the name for oak grove. With regard to the latter, it seems very fitting that the plantation town of Londonderry may have been constructed from as many as 150,000 oaks.
Myth, Legend and Folklore
In myth and legend, the oak is associated with themes of longevity, strength, fertility and kingship and connected with the symbolism of the bull, pig and eagle. It is also thought to have been sacred to the druids. It features significantly in Celtic lore and was linked to the worship of the Celtic Jupiter. Some of the stories from Irish mythology demonstrate that the oak was connected with fairies, spirits, magic and the otherworld, often being used to cast spells for protection against enemies.
Literature
The popularity of the oak through the ages is visible in Irish literature. For example, the early Irish poem, ‘The Plain of Mugna’, praises the tree of Mugna, an oak planted in honour of the birth of the King, Conn Céadchathach. Perhaps intended to reflect Conn’s reign, the tree of Mugna was renowned for its inordinate and incomparable scale, strength and bounty. The oak also features in J. M. Synge’s 1911 poem, ‘To the Oaks of Glencree’ and more recently in Mario Corrigan’s poem, ‘The Battle for Coman’s Wood’, written in 2015.
Value to wildlife
Our two native oak trees are often described as the kings of biodiversity. Research by the UK Centre for Ecology and Hydrology revealed that in the UK, 2300 animals and plants are associated with the two native oaks, which are also native to Ireland. Of these species, 326 are found solely on oak, and a further 229 species are rarely found on species other than oak.
Oaks can live for 1,000 years! As they grow and age, they become more valuable for wildlife, developing cavities, dead wood, and other features plants and animals love. Decaying wood is a haven for beetles, with cavities making great bat roosts, squirrel dens and bird nesting spots.
The oak flowers are eaten by red squirrels and many insects, including the caterpillar of the purple hairstreak butterfly, which relies solely on oak. Larvae of goat moths, the largest in Ireland, burrow into the trunk and feed on the wood for up to five years until it is ready to pupate.
As autumn descends, the oak's leaves fall to the ground and break down into a nutrient-rich leaf mould, nourishing the earth beneath. Beetles and multiple different fungi flourish in this fertile ground.
Threats
The Oak Processionary Moth is known for damaging tree foliage and rendering oaks more susceptible to diseases. This moth was recently spotted in Dublin in June 2020 and again in June 2023. After these reports, prompt action led to their swift removal and eradication. However, they are now established in the UK and could reappear in Ireland.
To learn more about threats to Irish trees, visit 'Threats to Trees.'
Uses
The oak tree is celebrated for its excellent timber and has been central to human craftsmanship for centuries. Even today, it is cherished for its beauty and strength, making it a preferred choice for furniture-making, veneers, and constructing casks.
Beyond its role in woodworking, the oak has a legacy in traditional medicine. Its leaves, bark, and acorns were once believed to possess healing powers, with remedies prescribed for ailments ranging from diarrhoea to inflammation and kidney stones.
References
Forestry Focus. 2023. ‘Trees in Irish Placenames’, Forestry Focus Website. Online resource: Trees in Irish Place Names - Forestry Focus
Kelly, F. 1999. Trees in Early Ireland, Augustine Henry Memorial Lecture 11th March 1999, Irish forestry: Journal of the Society of Irish Foresters, 56, 39-57.
Leroy, T., Plomion, C. and Kremer, A. 2020. Oak symbolism in the light of genomics. New phytologist, 226(4), 1012-1017.
Literature and Ireland’s Trees. 2023. Literature and Ireland’s Trees. Online: LIT: Literature and Ireland's Trees (litliteratureandirelandstrees.com)
MacCoitir, N. 2015. Ireland’s Trees: Myths, Legends and Folklore. Cork: The Collins Press.
McMahon, P. 2023. Island of Woods: How Ireland Lost Its Forests and How to Get Them Back, Dublin: New Island Books.
Neeson, E. 1991. A History of Irish Forestry, Dublin: The Lilliput Press Ltd.
Raftery, B. 1996. Trackway Excavations in the Mountdillon Bogs, Co. Longford, Irish Archaeological Wetland Unit Transactions: Volume 3, Dublin: Crannóg Publishing.
Shokouhi, M. 2019. Despirited Forests, Deforested Landscapes: The Historical Loss of Irish Woodlands, Études Irlandaises, 44(1), 17-30. DOI: https://doi.org/10.4000/etudesirlandaises.6812
Stroh, P. A., Humphrey, T. A., Burkmar, R. J., Pescott, O. L., Roy, D. B., & Walker, K. J. 2023. BSBI Online Plant Atlas 2020. https://plantatlas2020.org/atlas
Tree Council of Ireland. 2024. Native Irish Trees. Tree Council of Ireland. https://www.treecouncil.ie/native-irish-trees
Woodland Trust. 2024. A-Z of British trees. Woodland Trust. https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/