Sycamore
Invasive Species Information

Creeping Bellflower - Campanula rapunculoides Biodiversity Medium Risk Invasive Species 14

What Is Sycamore - (Acer pseudoplatanus)?
Habitat: Terrestrial
Distribution in Ireland: Naturalised and widely planted
Status: Established
Family name: Sapindaceae (Soapberry family)
Common name/s: Sycamore Maple, Great Maple

Reproduction:

Seed Dispersal: The winged seeds (samaras) are dispersed by wind, allowing them to travel considerable distances from the parent tree.
Regrowth: The tree can also regenerate from stumps and root suckers if cut down, which contributes to its persistence in managed woodlands.

Clover broomrape Biodiversity Medium Risk Invasive Species 14

Sycamore Seed

In Ireland, Sycamore is naturalised and widely planted, often used in forestry, landscaping, and as a street tree.

However, it is considered invasive in some areas, particularly in woodlands and semi-natural habitats, where it can spread rapidly and outcompete native species. Its ability to self-seed prolifically allows it to establish dense stands that may alter woodland composition.

Sycamore Leaf

Sycamore is native to central and southern Europe and has been widely introduced to other regions, including North America and the British Isles. It thrives in a variety of habitats, including:

Woodlands and Forests: Commonly found in mixed woodlands, where it can grow as a dominant or co-dominant species.
Urban Areas: Frequently planted in parks, gardens, and along streets due to its ability to tolerate pollution, compacted soils, and harsh urban conditions.
Disturbed Areas: Readily establishes in disturbed sites, such as roadsides, hedgerows, and abandoned fields, where it can colonise open spaces quickly.

The tree is adaptable to a range of soil types, including clay, loam, and sandy soils, and grows best in moist, well-drained conditions. It prefers full sun to partial shade but is tolerant of shade when young.

How To Identify Sycamore?

Sycamore - Acer pseudoplatanus ID Card V7-4.png

Leaf: The leaves are large, palmate, and lobed
Flower: Produces greenish-yellow, pendulous flower clusters (racemes)
Bark: The bark is smooth and grey on young trees, becoming rougher and flaky with age
Fruit: Forms winged seeds (samaras), each about 3-5 cm long
Height: Typically grows to a height of 20 to 35 metres
Root: Sycamore has a deep and spreading root system

Sycamore - Acer pseudoplatanus ID Guide

Sycamore Leaves & Seeds

Sycamore Bud

Sycamore Bark

Sycamore Flower

Why Is Sycamore A Problem?

Sycamore can have various ecological impacts, especially in areas where it becomes dominant:

Competition with Native Species: It can outcompete native tree and shrub species, particularly in woodlands, where its dense canopy can reduce light availability for understory plants.
Changes in Soil Chemistry: The leaf litter from Sycamore may alter soil pH and nutrient levels, potentially affecting the growth of other plants.
Wildlife Habitat: While the tree provides habitat and food for some species (e.g., pollinators attracted to the flowers and birds eating the seeds), its spread can displace more ecologically valuable native trees that support a wider range of wildlife.