Short description of Acer pseudoplatanus, Sycamore

A large deciduous tree with typical maple shaped leaves – simple with five main coarsely serrate lobes. Flowers are produced in pendent yellow-green panicles and occur with the leaves. The characteristic fruit ‘keys’ have wings that are divergent at about 90°.

Impact summary: Acer pseudoplatanus, Sycamore

Has the ability to displace native tree species from woodlands. Is considered to support a lower number of associated insect species than native trees, thus lowering the biodiversity of woodlands. Its dense canopy can affect the woodland floor flora.

Habitat summary: Acer pseudoplatanus, Sycamore

Sycamore can be found in all types of British woodland, as well as disturbed and urban sites. In upland areas they are restricted to areas of habitation. It is tolerant of air pollution and salt spray.

Overview table

Environment	Terrestrial
Species status	Non-Native
Native range	Caucasus
Functional type	Land plant
Status in England	Non-Native
Status in Scotland	Non-Native
Status in Wales	Non-Native
Location of first record	v.c.15
Date of first record	1632

Origin

Sycamore is a temperate species native to Central Europe, ranging from Belgium to the Caucasian Mountains and from Germany to Italy.

First Record

There is debate about when Sycamore was first introduced into GB, but it is considered to be around the 15^th or 16^th century, although Roman introduction can not be excluded. It was first recorded in the wild in 1632.

Pathway and Method

Subsequent to its introduction, Sycamore has been widely planted, especially during the 18^th century, as an amenity plant. As a consequence, combined with its ability to rapidly grow and produce vast quanitites of seed, it can now be found throughout the British Isles.

Species Status

Sycamore has been introduced throughout the temperate world, including North America, South America, Europe and New Zealand, mainly for amenity planting. Throughout this range it readily regenerates and has been noted as invasive in a number of countries, including New Zealand, Madeira and Patagonia.

Dispersal Mechanisms

Its winged seeds are wind dispersed over relatively short distances (30 - 80m), although seed can be dispersed over several kilometers. Despite high seed production invasion speed is generally slow due to the infrequency of suitable conditions for regeneration to occur.

Reproduction

Sycamore is monoecious, however, some plants only produce male flowers. It is insect pollinated, mainly by bees, and is wind dispersed.

Known Predators/Herbivores

Seeds and saplings are eaten by rodents, while slugs are the main predators of seedlings.

Resistant Stages

Due to mass germination of seeds in the spring there is no, or little, soil seed bank.

Habitat Occupied in GB

In GB sycamore occupies a range of different woodlands. From ancient woodlands, semi-natural woodlands and disturbed sites. It has no preference to the type of woodland and can be found, for example, in oak, beech, ash and alder woods. It is also an urban species found in disturbed areas and along railway lines.

Distributed throughout GB.

Environmental Impact

Sycamore in comparison to other native woodland species casts dense shade, thus impacting upon the ground flora. Additionally it is considered to support fewer associated herbiverous insects. The flowers provide an important source of food for several insect species in early spring. Compared to other GB tree species it can maintain an above average species richness of epiphytic lichens. As a gap species it can quickly establish following disturbance and as a result displace native woodland tree species.

Health and Social Impact

In the south, sycamore is commonly prone to Sooty Bark Disease. This is known to cause pneumonia in humans. With proposed future changes in climate this sycamore disease could become more prevalent and hence result in a higher potential hazard to human health.

Economic Impact

Sycamore is increasingly being seen as an important timber tree, provenance trails are underway to improve sycamore planting material for the forestry. On protected areas sycamore is targeted for removal. Forestry Commission Scotland, for example, put an estimated cost of £300 per hectare for the removal of sycamore in their Scottish Programme for Protected Woodland Sites, noting that this was double the standard cost of tree thinning.

Identification

Stace, C. (2010) New Flora of the British Isles. 3^rd edition. Cambridge

Biology, ecology, spread, vectors

Binggeli, P. (1992) Patterns of invasion of sycamore (Acer pseudoplatanus L.) in relation to species and ecosystem attributes. D.Phil. Thesis, The University of Ulster. http:members.multimania.co.ukWoodyPlantEcologysycamoresycamore.htm

Management and impact

Binggeli, P. (1994) Controlling the invader. Tree News, Autumn, 14-15.

Binggeli, P. (1993) Conservation value of sycamore. Quarterly Journal of Forestry, 87, 143-146.

English Nature (2005) Audit of non-native species, English Nature research reports No.662

General

Morton-Boyd, J. (1993) Sycamore and Conservation. Tree News, Summer, 14-16.

Jones, E.W. (1945b). Biological flora of the British Isles - Acer L. Journal of Ecology, 32, 215-237.

DEFRA (2008) The Invasive Non-Native Species Framework Strategy for Great Britain.

Online Atlas of the British and Irish Flora - online resource available from
http:www.brc.ac.ukplantatlasindex.php?q=plantacer-pseudoplatanus