Acer pseudoplatanus | Sycamore | Seiceamóir



Conservation status

Not Assessed

Native status


First reported in the wild



Invasive species - risk of Medium Impact

Irish status


Introduction pathways - 1

Release in Nature

Introduction pathways subclass - 1

Landscape/flora/fauna improvement

Introduction pathways - 2

Escape from Confinement

Introduction pathways subclass - 2

Ornamental purpose

Invasive score


NAPRA Ireland risk assessed


Species Biology


Tree, up to 35m tall, simple leaves with 5 acute coarsely serrate lobes wider at the base, distinctive fruit with wings diverging at 90° (Stace, 1997).

Flowers: May; catkins and flowers

Fruits: Acorns borne on stalks <2cm long

Twigs & bark:  Twigs grey; bark grey and fissured when mature


Originally thought to be damaging to native woodlands and to support a much narrower range of diversity than native species it has been shown to support a wide range of lichens and other species (Leslie, 2005). The principal concern would be sycamore dominated woodlands, though sycamore seedlings are out competed by ash under sycamore canopy and vice versa (Walters & Savill, 1991), would suggest that there is a pattern of succession in mixed woodlands. Undisturbed woodlands have relatively few sycamore compared to disturbed sites, even when sycamore are present at nearby sites (Morecroft et al., 2008) and sycamores poor growth in dry conditions (Morecroft et al., 2008), would suggest careful management of forests can mitigate any effects of sycamore invasion.


Woodland, forest and other wooded land, Constructed, industrial or other artificial habitats

Pathway and vector description

Thought to have been planted in Derry around 1610 (Reynolds, 2002), widely planted in parks and gardens by the end of the 19th century it was only found once in the wild despite seeding freely (Reynolds, 2002). Has since expanded widely throughout Ireland.

Mechanism of impact


Broad environment


Habitat description

Found in woodlands, planted for forestry and widely planted as an ornamental in parks and roadsides (Reynolds, 2002), prefers acidic soils.

Species group


Native region



World distribution(GBIF)

Irish distribution

Established - Widespread & Common. One of the most common tree species in Ireland, naturalised in the wild and widely planted in semi-natural and urban habitats (Reynolds, 2002).

Native distribution

Native to central and southern Europe.

Temporal change

Date of first record category


Fifty year date category


Records submitted to Data Centre in 2024

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How can you help

Report any sightings to the National Biodiversity Data Centre.



Cronk Q.C.B. & Fuller, J.L. (1995). Plant invaders: the threat to natural ecosystems. London, UK; Chapman & Hall Ltd.

Leslie, A.D. (2005) The ecology and biodiversity value of Sycamore (Acer pseudoplatanus) with particular reference to Great Britain. Scottish Forestry. Vol 59 No 3. p19 -26.

Morecroft, M. D., Stokes, V. J., Taylor, M. E., & Morison, J. I. (2008). Effects of climate and management history on the distribution and growth of sycamore (Acer pseudoplatanus L.) in a southern British woodland in comparison to native competitors. Forestry, 81(1), 59-74.

Reynolds, S.C.P. (2002) A catalogue of alien plants in Ireland. National Botanic Gardens. Glasnevin, Dublin.

Stace, C. (1997). New Flora of the British Isles 2nd Edition. Cambridge University Press, Cambridge.

Waters, T. L., & Savill, P. S. (1992). Ash and sycamore regeneration and the phenomenon of their alternation. Forestry, 65(4), 417-433.

CABI Datasheet