Acer bohemicumC.Presl ex Opiz. (1852)(invalid name)
Acer dittrichiiOrtm. (1831)
Acer erythrocarpumDippel (1892)
Acer euchlorumDippel (1892)
Acer fieberi Opiz (1852)(invalid name)
Acer hybridumBosc (1821)
Acer majusGray (1821)
Acer melliodorumOpiz (1852)
Acer montanumGarsault (1764)(invalid name)
Acer opiziiOrtmann ex Opiz. (1852)
Acer opulifoliumThuill. (1790)(illegitimate name)
Acer procerumSalisb. (1796)
Acer purpureumDippel (1892)
Acer quinquelobumGilib. (1782)(invalid name)
Acer rafinesquianumDippel (1892)
Acer villosumC. Presl (1822)
Acer wondracekiiOpiz (1852)
Acer worleeiDippel (1892)
Acer pseudoplatanus, known as thesycamore in theBritish Isles and as thesycamore maple in the United States,[3] is a species ofmaple native toCentral Europe andWestern Asia. It is a largedeciduous, broad-leavedtree, tolerant of wind and coastal exposure.
Although native to an area ranging fromFrance eastward toUkraine, northernTurkey and theCaucasus, and southward to the mountains ofItaly and northernIberia, the sycamore establishes itself easily from seed and was introduced to theBritish Isles by 1500. It is nownaturalised there and in other parts of Europe, North America, Australia and New Zealand, where it may become aninvasive species.[4]
The sycamore can grow to a height of about 35 m (115 ft) and the branches form a broad, roundedcrown. Thebark is grey, smooth when young and later flaking in irregular patches. The leaves grow on longleafstalks and are large andpalmate, with five large radiating lobes. The flowers are greenish-yellow and hang in dangling flowerheads calledpanicles. They produce copious amounts ofpollen andnectar that are attractive to insects. The winged seeds orsamaras are borne in pairs and twirl to the ground when ripe. Theygerminate freely in the following spring.
In its native range, the sycamore is associated with abiodiverse range of invertebrates and fungi, but these are not always present in areas to which it has been introduced. It is sometimes planted in urban areas for its value as anornamental. It produces a hard-wearing, creamy-white close-grained timber that is used for making musical instruments, furniture, joinery, wood flooring and kitchen utensils. It also makes good firewood. The risingsap in spring has been used to extract sugar and makealcoholic and non-alcoholic drinks, and can be processed into a syrup similar to that of thesugar maple. Bees often collect thenectar to make honey.
The specific namepseudoplatanus refers to the superficial similarity of the leaves and bark of the sycamore to those of plane trees in thegenusPlatanus, the prefixpseudo- (from Ancient Greek) meaning "false". However, the twogenera are in differentfamilies that are only distantly related.[5]Acer andPlatanus differ in the position in which leaves are attached to the stem (alternate inPlatanus, paired or opposite inAcer) and in their fruit, which are spherical clusters inPlatanus and pairedsamaras (winged fruit) inAcer.[6]
The common name "sycamore" was originally applied to thefig speciesFicus sycomorus, the sycamore or sycomore referred to in theBible, that is native to Africa and Southwest Asia.[7] Other common names for the tree includefalse plane-tree,[8]great maple,[8]Scottish maple,[8]mount maple,[9]mock-plane,[10][11] orCeltic maple.[12]
Illustration of twigs, buds, leaves, flowers and fruitsAcer pseudoplatanus can form a broad, domed crown.Acer pseudoplatanus in early October inLower Austria
The sycamore is a large, broad-leaveddeciduous tree that reaches 20–35 m (66–115 ft) tall at maturity, the branches forming a broad, domedcrown. The bark of young trees is smooth and grey but becomes rougher with age and breaks up into scales, exposing the pale-brown-to-pinkish inner bark.[13]: 118
Sycamore shoot tip in winter with a green terminal bud and paired green lateral buds
The buds are produced in opposite pairs,ovoid (approximately oval in shape) and pointed, with the bud scales (the modified leaves that enclose and protect the bud) green, edged in dark brown and with dark brown tips, 0.5–1 centimetre (1⁄4–3⁄8 in).[13] When the leaves are shed they leave horseshoe-shaped marks calledleaf scars on the stem. Theleaves are opposite, large, 10 to 25 cm (4 to 10 in) long and broad,palmate with 5 pointed lobes that are coarsely toothed orserrated.[13][14]: 372 They have a leathery texture with thick veins protruding on the underside. They are dark green in colour with a paler underside. Somecultivars have purple-tinged or yellowish leaves. The leaf stalk orpetiole is 5 to 15 cm (2 to 6 in) long, is often tinged red[13][15][16] with nostipules or leaf-like structures at the base.[13]
Thefunctionally monoecious or dioecious[citation needed] yellow-greenflowers are produced after the leaves in early summer, in May or June in the British Isles,[14]: 394 [17]: 396 on pendulouspanicles 10 to 20 cm (4 to 8 in) long with about 60–100 flowers on each stalk.[13] The fruits are paired winged seeds or samaras, theseeds5 to 10 mm (1⁄4 to3⁄8 in) in diameter, each with a wing20 to 40 mm (3⁄4 to1+5⁄8 in) long developed as an extension of the ovary wall. The wings are held at about right angles to each other,[14] distinguishing them from those ofA. platanoides andA. campestre, in which the wings are almost opposite,[14] and from those ofA. saccharum, in which they are almost parallel. When shed, the wing of the samara catches the wind and rotates the fruit as it falls, slowing its descent and enabling the wind to disperse it further from the parent tree. The seeds are mature in autumn about four months after pollination.[15][16]
The sycamore istetraploid (each cell having four sets of chromosomes, 2n=52), whereasA. campestre andA. platanoides arediploid (with 2 sets of chromosomes, 2n=26).[14]
Sycamore trees produce their flowers in hanging branched clusters known aspanicles that contain a variety of different flower types. Most are morphologicallybisexual, with both male and female organs, but function as if they were unisexual. Some are both morphologically and functionally male, others morphologically bisexual but function as males, and still others are morphologically bisexual but function as females. All of the flower types can producepollen, but the pollen from functionally female flowers does notgerminate. All flowers producenectar, the functionally female flowers producing it in greater volume and with a higher sugar content.[18]
Sycamore trees are very variable across their wide range and have strategies to preventself-pollination, which is undesirable because it limits the genetic variation of the progeny and may depress their vigour.[19] Mostinflorescences are formed of a mixture of functionally male and functionally female flowers. On any one tree, one or other of these flower types opens first and the other type opens later. Some trees may be male-starters in one year and female-starters in another. The change from one sex to the other may take place on different dates in different parts of thecrown, and different trees in any one population may come into bloom over the course of several weeks, so that cross-pollination is encouraged, although self-pollination may not be completely prevented.[18]
The sycamore is native to central and eastern Europe and western Asia. Its natural range includes Albania, Austria, Belgium, Bulgaria, Czech Republic, France, Georgia, Germany, Greece, Hungary, Italy, Lithuania, Netherlands, Poland, Portugal, Romania, southern Russia, Spain, Switzerland,East Thrace and theformer Yugoslavia.[4][21][22] Reports of it occurring in eastern Turkey have been found to refer toA. heldreichii subsp.trautvetteri.[4]It was probably introduced into Britain in theTudor period by 1500[23] and was first recorded in the wild in 1632 inKent.[24]: 28 [25] The date of its first introduction intoIreland is unclear, but the oldest specimen in Ireland is inCounty Cavan and dates from the seventeenth century.[26] It was introduced into Sweden around 1770 with seeds obtained from Holland.[27][28]: 76
The lack of old native names for it has been used to demonstrate its absence in Britain before introduction in around 1487, but this is challenged by the presence of an oldScottish Gaelic name for the tree,fior chrann which suggests a longer presence in Scotland at least as far back as the Gaelic settlement atDál Riata in the late 6th and early 7th centuries. This would make it either anarchaeophyte (anaturalised tree introduced by humans before 1500) or perhaps native if it can be seen to have reached Scotland without human intervention.[29]: 6 At the moment it is usually classified as aneophyte, a plant that is naturalised but arrived with humans on or after the year 1500.[12] Today, the sycamore is present in 3,461 (89.7%) ofhectads in Britain, more than any native tree species.[30]: 388 [31]
The sycamore has been introduced to suitable locations outside Europe as an attractive tree for park, street or garden. These include the United States, Canada, Australia (Victoria andTasmania), Chile and New Zealand,[4][32]Patagonia[25] and thelaurel forests ofMadeira and theAzores.[33]: 74 At the time of its introduction it was probably not appreciated that its prolific production of seeds might one day cause a problem to the landscape as it spread and out-competed native species.[34]: 334 The tree is now considered to be an environmental weed in some parts of Australia (Yarra Ranges, Victoria) and alsoMount Macedon, nearDaylesford, parts of theDandenong Ranges, where it is naturalised in theeucalypt forests.[35] The sycamore is also scattered in north-eastern Tasmania and also atTaroona, near theDerwent River, in southern Hobart. It is considered to be aninvasive species in New Zealand,[36] Norway,[37] and environmentally sensitive locations in the United Kingdom.[38]
In its native range, the sycamore is a natural component of birch (Betula sp.), beech (Fagus sp.) and fir (Abies sp.) forests.[40] It readily invades disturbed habitats such as forest plantations, abandoned farmland andbrownfield land, railway lines and roadsides verges, hedgerows, native and semi-natural woodland. In New Zealand, it invades the high country tussock grassland. As an introduced, invasive species, it may degrade the laurel forest in Madeira and Portugal and is a potential threat to the rareendemic Madeiran orchid,Dactylorhiza foliosa.[23]
It is tolerant of a wide range of soil types and pH, except heavy clay, and is at its best on nutrient-rich, slightly calcareous soils. The roots of the sycamore form highly specific beneficialmycorrhizal associations with the fungusGlomus hoi, which promotesphosphorus uptake from the soil.[41] Sycamore mycorrhizas are of the internalarbuscular mycorrhizal type, in which the fungus grows within the tissues of the root and forms branched, tree-like structures within the cells of the root cortex.[41]
The larvae of a number of species ofmoth use the leaves as a food source. These include thesycamore moth (Acronicta aceris), the maple prominent (Ptilodon cucullina) and the plumed prominent (Ptilophora plumigera).[5] Thehorse-chestnut leaf miner (Cameraria ohridella) occasionally lays its eggs on the sycamore, although 70% of the larvae do not survive beyond the secondinstar.[42]: 24 The leaves attract aphids, and also theladybirds andhoverflies that feed on them. The flowers produce copious amounts of nectar and pollen and are attractive to bees and other insects, and the seeds are eaten by small mammals such asvoles and birds.[5] As an introduced plant, in Britain the sycamore has a relatively small associated insect fauna of about 15 species,[43] but it does have a larger range ofleafhoppers than does the native field maple.[44]
The tree may also be attacked by thehorse chestnut scale insect (Pulvinaria regalis), which sucks sap from the trunk and branches, but does not cause serious damage to the tree.[45] Sometimes squirrels will strip the bark off branches, girdling the stem; as a result whole branches may die, leaving brown, wilted leaves.[46]
The sycamore gall miteEriophyes macrorhynchus[47] produces small redgalls, similar to those of the nail gall miteEriophyes tiliae, on leaves of sycamore and field maple,Acer campestris from April onwards.[48]: 179 Another mite,Aceria pseudoplatani causes a 'sycamore felt gall' on the underside of leaves of both sycamore and Norway maple (Acer platanoides).[49] The sycamore aphidDrepanosiphum platanoidis suckssap from buds and foliage, producing large quantities of stickyhoneydew that contaminate foliage, cars and garden furniture beneath.[48]: 119
The sycamore is susceptible to sooty bark disease, caused by the fungusCryptostroma corticale. This causes wilting of the crown and the death of branches. Rectangular patches of bark become detached exposing thick layers of black fungal spores. The fungus may be present in theheartwood without symptoms for many years, working its way towards the bark following long, hot summers.[50] The spores are hyper-allergenic and cause a condition called maple bark stripper's disease, ahypersensitivity pneumonitis.[51][52] Less serious is the fungusRhytisma acerinum which often forms the disease known as tar spot, in which black spots with yellow margins form on the foliage. The leaves may fall prematurely but the vigour of the tree is little affected.[53] Sycamore leaf spot, caused by the fungusCristulariella depraedans, results in pale blotches on leaves which later dry up and fall. This disease can cause moderate leaf loss but trees are little affected in the long run.[46]
Sycamore self-seeds very vigorously,[30]: 388 the seeds germinatingen masse in the spring so that there is little, or no, seed bank in the soil.[25] It is readily propagated from seed in cultivation, but varieties cannot be relied on to breed true.[57] Specialcultivars such asA. pseudoplatanus 'Brilliantissimum' may be propagated by grafting.[57][58]: 92 This variety is notable for the bright salmon-pink colour of the young foliage and is the only sycamore cultivar to have gained theRoyal Horticultural Society'sAward of Garden Merit.[57]: 92 A rareweeping form with dangling branches,A. pseudoplatanus var.pendulum, was first sold byKnight & Perry's exotic nursery in Chelsea, England, before 1850 when the name was published by W.H. Baxter in the Supplement to Loudon'sHortus Brittanicus, but no specimens of this cultivar are known to survive.[59]
The sycamore is noted for its tolerance of wind, urban pollution, salt spray, and low summer temperatures, which makes it a popular tree for planting in cities, along roads treated with salt in winter, and in coastal localities. It is cultivated and widelynaturalised north of its native range in Northern Europe, notably in the British Isles and Scandinavia north toTromsø, Norway (seeds can ripen as far north as Vesterålen);Reykjavík,Iceland; andTórshavn on theFaroe Islands. It now occurs throughout the British Isles, having been probably introduced in the 16th century.[60]: 439
Sycamores make new growth from the stump or roots if cut down and can therefore becoppiced to produce poles and other types of small timber. Its coppicestools grow comparatively rapidly, reaching as much as 1.3 metres (4 ft 3 in) in length in the first year after initial harvesting.[61]
It is grown as a species for medium-to-largebonsai in many areas of Europe, where some fine specimens can be found.[62]
Sycamore is planted in parks for ornamental purposes, and sometimes as a street tree, for its tolerance of air pollution makes it suitable for use in urban plantings. Owing to its tolerance to wind, it has often been planted in coastal and exposed areas as awindbreak.[63]
It produces a hard-wearing, white or cream close-grainedtimber that turns golden with age. The wood can be worked and sawn in any direction and is used for making musical instruments, furniture,joinery,wood flooring andparquetry. Because it is non-staining, is used for kitchen utensils, wooden spoons, bowls, rolling pins and chopping boards. In Scotland it has traditionally been used for making fine boxes, sometimes in association with contrasting, dark-colouredlaburnum wood.[64]
Occasionally, trees produce wood with a wavygrain, greatly increasing the value for decorativeveneers.[65] The wood is a medium weight for a hardwood, weighing 630 kg per cubic metre.[66] It is a traditional wood for use in making the backs, necks and scrolls ofviolins. The wood is often marketed as rippled sycamore.[67]Whistles can be made from straight twigs when the rising sap allows the bark to be separated,[68] and these, and sycamore branches, are used in customs associated with early May inCornwall.[40] The wood is used for fuel, being easy to saw and to split with an axe, producing a hot flame and good embers when burnt.[69]
In Scotland, sycamores were once a favoured tree for hangings, because their lower branches rarely broke under the strain.[69] Both male and female flowers produce abundant nectar, which makes a fragrant, delicately flavoured and pale-coloured honey. The nectar and copious dull yellow ochrepollen are collected byhoneybees as food sources.[70]: 4, 46 [71] Thesap rises vigorously in the spring and like that of sugar maple can be tapped to provide a refreshing drink, as a source of sugar and to make syrup or beer.[24]: 57 [72]
Under this sycamore tree atTolpuddle inDorset, England, six agricultural labourers, known as theTolpuddle Martyrs, formed an earlytrades union in 1834. They were found to have breached theUnlawful Oaths Act 1797 and weretransported to Australia. The subsequent public outcry led to their release and return.[73] The tree now has a girth of 5.9 metres (19 feet, 4 inches)[74] and a 2005 study dated the tree to 1680.[75] The tree is cared for by theNational Trust, which haspollarded the tree in 2002 and 2014.[76]
An ancient sycamore (sometimes described as a "plane") with distinctive yellow foliage formerly stood in the village ofCorstorphine, now a suburb ofEdinburgh, Scotland. The tree was reputedly planted in the 15th century and is named as the formAcer pseudoplatanus f.corstorphinense Schwer. Not only was it claimed to be the "largest sycamore in Scotland" but also the scene ofJames Lord Forrester's murder in 1679.[77] The tree was blown down in a storm onBoxing Day 1998, but a replacement, grown from acutting, now stands in the churchyard of Corstorphine Kirk.[78] The tree is commemorated in the badge of the Corstorphine Bowling Club of Edinburgh, designed in 1950 to feature the Corstorphine sycamore tree and a single horn, and redesigned in 1991 for the club's centenary.[79]
TheNewbattle Abbey sycamore nearDalkeith, planted in 1550, was the specimen with the earliest known planting date in Scotland. It had achieved a girth of 5 m (16 ft) and a height of 26 m (85 ft)[80]: 6 by the time it was toppled by a gale in May 2006 at the age of 456 years.[81]
Saint Fintan founded a monastery atClonenagh inCounty Laois, Ireland, in the sixth century and it had a spring beside it. This was considered holy and was visited by pilgrims. In the nineteenth century, a Protestant land owner, annoyed at people visiting the site, filled the well in, whereupon the water started to flow into the hollow interior of a sycamore tree on the other side of the road. Filled with amazement, people hung rags on the tree and pressed coins into its trunk asvotive offerings and it became known as the "Money Tree". Some years later, it fell down, but new shoots appeared from its base, and the water still welled up. It remains a place of veneration on St Fintan's day, February 17.[82]: 84–85
The Sycamore Gap Tree orRobin Hood Tree was a sycamore tree standing next toHadrian's Wall nearCrag Lough inNorthumberland, England. It was located in a dramatic dip in the landscape and was a popular photographic subject, described as one of the most photographed trees in the country. It derived its alternative name from featuring in a prominent scene in the 1991 filmRobin Hood: Prince of Thieves. According tothe National Trust, the tree was planted in the late 19th century[83] and once stood with others, but they had been removed over time, possibly to improve sightlines or for gamekeeping purposes.[84] It was felled overnight on 28 September 2023; a police investigation was launched the following day.[85] The perpetrators Daniel Graham and Adam Carruthers, who carried out the act for 'kicks', were convicted and jailed for four years on 15 July 2025.[86]
^abRushforth, K. (1999).A photographic guide to the trees of Britain and Europe. London: Collins.ISBN0-00-220013-9.
^abHumphries, C.J.; Press, J.R.; Sutton, D.A. (1992).Trees of Britain and Europe. UK: Hamlyn Publishing Group Ltd.ISBN0-600-57511-X.
^Blamey, M.; Fitter, R.; Fitter, A. (2003).Wild flowers of Britain and Ireland: The Complete Guide to the British and Irish Flora. London: A & C Black.ISBN978-1-4081-7950-5.
^Verbeek, I.; Copini, P.; Sass-Klaassen, U.; Dingemanse, A.; Buiteveld, J. (2021). Herkomstenonderzoek van gewone esdoorn (Acer pseudoplatanus) in Nederland (Report) (CGN rapport 52 ed.). Wageningen: Centre for Genetic Resources, the Netherlands (CGN), Wageningen University & Research.doi:10.18174/551151.{{cite report}}: CS1 maint: multiple names: authors list (link)
^"Acer pseudoplatanus L." Denmark: GBIF (Global Biodiversity Information Facility). Retrieved18 May 2016.
^Sequeira, M.; Espírito-Santo, M.D.; Aguiar, C.; Capelo, J.; Honrado, J. (2012).Checklist da Flora de Portugal (Continental, Açores e Madeira). Lisbon: ALFA (Associação Lusitana de Fitossociologia).ISBN978-989-20-2690-9.
^"Eriophyes macrorhynchus (Nalepa, 1889)". Natural History Museum, Centre for Ecology and Hydrology and Joint Nature Conservation Committee, UK. Retrieved19 May 2016.
^abBuczacki, S.; Harris, K. (1983).Collins shorter guide to the Pests, Diseases and Disorders of Garden Plants. London: Collins.ISBN0-00-219074-5.
^Preston, C.D.; Pearman, D.A.; Dines, T.D. (2002).New Atlas of the British and Irish Flora: An Atlas of the Vascular Plants of Britain, Ireland, The Isle of Man and the Channel Islands.Oxford University Press.ISBN978-0-19-851067-3.
^Cowper, A.S.; Aitchison, K. (2001)."The Corstorphine Sycamore Tree".www.corstorphine-trust.ukgo.com. The Corstorphine Trust. Archived fromthe original on 2 November 2014. Retrieved27 November 2014.
^Hendrie, J. (2010)."Capital Trees"(PDF).www.forestryjournal.co.uk. The Forestry Journal. Archived fromthe original(PDF) on 4 December 2014. Retrieved27 November 2014.
^"Club history". Corstorphine Bowling Club. 30 April 2012. Retrieved19 May 2016.
