General: Planetree family (Platanaceae). Monoecious, native, deciduous trees with an open crown, among the largest of Eastern deciduous forests, reaching heights of 18-37 meters, and the greatest diameter of any temperate hardwood tree -- the largest known range 3-4 meters d.b.h.; twigs zig-zag, with only lateral buds, these completely covered by a single scale within the petiole base and not visible until after the petiole detachment; bark of upper trunk exfoliating in patches, leaving areas of inner bark exposed, a patchwork of browns, yellows, and greens against a background of white, the darker bark with age falling away in thin brittle sheets, exposing younger and lighter-colored bark. Leaves are deciduous, alternate, 10-35 cm long, palmate-veined and roughly star-shaped, with 3-5 sharp lobes, the blades often as broad or broader than they are long, truncate to cordate at the base, on petioles to 12 cm long; a leaf-like stipule at the petiole base is persistent during early growth. Staminate and pistillate flowers in separate, tightly compacted, ball-shaped clusters. Fruit is single-seeded and indehiscent (an achene), 8-9 mm long, with a ring of bristles at the base, numerous achenes in a pendulous, ball-shaped fruiting head 2-5 cm in diameter, the individual achenes drifting in the wind if the head breaks up on the tree. Common name apparently borrowed from the European sycamore maple (Acer pseudoplatanus L.), which has similar leaves. That name in turn comes from the Middle Eastern sycomore fig, Ficus sycomorus L., its specific epithet from the Greek “sykomoros,” mulberry.
Variation within the species: geographic variation in sycamore is extensive, but variants are not currently formally recognized. Platanus occidentalis var. glabrata and P. occidentalis var. attenuata are treated as synonyms of the typical expression.
The similar London planetree (below) distinguished by the lobes of its larger leaves being somewhat longer and narrower (often longer than wide), the fruiting heads 1-2 on each stalk, and the bark often somewhat greener.
Regularity: Regularly occurring
Regularity: Regularly occurring
southern Ontario, southern Wisconsin, Iowa, and extreme eastern
Nebraska; south to south-central Texas; and east to northwestern Florida
and southeastern Georgia. It also occurs in the mountains of
northeastern Mexico [30,35,50]. Sycamore has become naturalized to some
extent from plantations outside of its native range, chiefly in southern
Maine, southern Michigan, southern Minnesota, and eastern and southern
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
14 Great Plains
Occurrence in North America
KS KY LA MD ME MA MI MN MO MS
NE NC NH NJ NY OH OK PA RI SC
TN VA VT WV WI ON MEXICO
It often is a pioneer on upland sites in the central part of its range, but it is primarily a species of bottomland and alluvial soils, also occurring on creek banks, mesic coves and lower slopes, on a wide range of soil types. It is a major pioneer species in the floodplains of large rivers and occurs on a variety of wet sites, including shallow swamps, sloughs, and wet river bottoms where soil is saturated 2-4 months during the growing season. Water dispersal often results in seed deposition on muddy flats highly conducive to germination because seed dispersal occurs when water is receding after spring floods. American sycamore is most commonly found in mixture with sweetgum, boxelder, silver and red maple, cottonwood, and willows. It is found at 0-300 (-750) meter elevation.
American sycamore can tolerate weeks of flooding, even complete submersion of seedlings, provided that the water is aerated. A significant portion of young sycamores can survive almost 2 months of continuously waterlogged soils during dormancy, but sycamore of various stages will die if the entire tree is inundated for more than two weeks during the growing season. Saplings top-killed by flooding may resprout from the root crown.
Flowers appear with the leaves in April-May or as early as late March in the South. Fruits ripen September-October (-November), usually breaking up and falling from the tree through the winter and into spring.
American sycamore is widespread in the eastern United States, from Texas to Nebraska, Iowa, and Wisconsin and into southern Ontario, Canada; apparently extirpated in Maine. It also occurs in the mountains of northeastern Mexico. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.
Sycamore is a native, deciduous tree. Although not the tallest, it is
amoung the tallest trees of eastern deciduous forests . Mature
heights range from 60 to 120 feet (18-37 m) [9,83]. Reported diameters
range from 2 to 6.6 feet (0.6-2 m) . The bark of young trunks has
small scales. Bark at the base of large trunks is deeply furrowed and
up to 3 inches thick (7.6 cm) ; on the upper portions of the trunk
the bark exfoliates in patches, leaving areas of inner bark exposed
[30,78]. The leaves are 4 to 10 inches (10-25.4 cm) long, often as
broad or broader than they are long . Sycamores form widespread,
strongly branched root systems . The fruit is a plumed achene ;
numerous fruits are tightly aggregated into a ball-shaped fruiting head
0.8 to 2 inches (2-5 cm) in diameter [9,13].
Sycamore is characterized by rapid growth throughout its life; it is
also long lived (over 250 years) .
A sycamore measuring 140 feet (43 m) tall and 120 inches (305 cm) dbh
has been reported; a specimen from Indiana was reported as 168 feet (51
m) tall and 33 feet (10 m) in circumference. Open-grown individuals can
achieve a crown spread of 100 feet (30 m) or more . A survey of big
trees in seven mid-southern states reported that the second and fourth
largest trees (of all species) were sycamores. The largest sycamore in
these states was a Tennessee tree 140 feet tall (42.67 m) and 65.9
inches (167.4 cm) dbh, with a circumference of 207 inches (525.8 cm),
the largest circumference of any tree in these states .
Catalog Number: US 70817
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): E. Palmer
Year Collected: 1880
Locality: States of Coahuila and Nuevo Leon., Coahuila / Nuevo León, Mexico, North America
Catalog Number: US 930889
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): C. G. Pringle
Year Collected: 1900
Locality: By streams near Diaz., Coahuila, Mexico, North America
Elevation (m): 213
Catalog Number: US 963591
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): C. G. Pringle
Year Collected: 1900
Locality: By streams near Diaz., Coahuila, Mexico, North America
Elevation (m): 213
Sycamore is primarily a species of alluvial soils along streams and in
bottomlands, but occurs occasionally as a pioneer on drier upland slopes
[13,30.78]. It occurs on a wide variety of soils, including both sands
and clays . Its best growth occurs on sandy loams or loams with a
good supply of ground water but it also occurs on wet muck, shallow peat
and other, more poorly drained bottomland soils .
Sycamore occurs on a variety of wet sites, including shallow swamps,
sloughs, and very wet riverbottoms where soil is saturated 2 to 4
months during the growing season . Sycamore seedlings survived
almost 2 months of continuously waterlogged soils . In a greenhouse
experiment, after experiencing 60 days of completely waterlogged soils,
about half of current-year seedlings died shortly after their removal
from the water; none died with shorter treatment periods . Sycamore
is more tolerant of poorly drained soils in the northern parts of its
range. It was given an adaptation value of 7.5 (out of a maximum of 10)
for moisture tolerance . Sycamore has a recommended lower pH range
of 4.0 to 4.5 
Sycamore is rated as moderately tolerant of flooding. In the Northeast,
sycamore occurs on sites with greater than 98 percent probability of
flooding in any given year . In Illinois, sites that experience
flooding approximately 3 months of the year are dominated by silver
maple, sycamore, and green ash (Fraxinus pennsylvanica var. lanceolata).
These sites are usually flooded before the growing season; sycamore is
intolerant of flooding during the growing season and will die if the
entire tree is inundated for more than 2 weeks . Saplings may be
more resilient than mature trees due to their higher sprouting capacity;
Baker  reported that even though 4 weeks of flooding appeared to have
killed 65 percent of sycamore saplings, 90 percent of the saplings were
alive at the end of one growing season following flooding. Most of them
had only been top-killed and subsequently sprouted from the root crown
. Seedlings are less tolerant of flooding than larger plants simply
because they are more likely to be completely covered by water during
active growth. Only 28.8 percent of scyamore seedlings survived
complete inundation for 5 days during a June flood as compared to a
survival rate of 88.9 percent for unflooded seedlings .
The elevational range of sycamore extends from sea level to 1,000 feet
(305 m) in the northern parts of its range and to 2,500 feet (762 m) in
the southern Appalachians [13,78].
Key Plant Community Associations
Sycamore is found in quantity only in bottomland forests, particularly
of elm-ash-cottonwood (Ulmus spp.-Fraxinus spp.-Populus deltoides) types
as defined by Shifley and others , and cottonwood-willow (Salix
spp.) types. It usually occurs singly or in small groups .
Sycamore is found occasionally along intermittent streams within upland
stands of oak-hickory (Quercus spp.-Carya spp.) communities. It is a
major pioneer species in the floodplains of large rivers . In the
Southeast pure stands of 40 to 100 acres (16-40 ha) are sometimes
formed; it rarely forms extensive pure stands in the northern parts of
its range . In the northern states sycamore is rarely the dominant
species; it increases (replacing silver maple [Acer saccharinum]) with
decreasing latitude .
Sycamore is listed as a dominant or indicator species in the following
1) The natural forests of Maryland: an explanation of the vegetation map
of Maryland 
2) The natural communities of South Carolina 
3) Land Classification in the Blue Ridge province: state-of-the-science
4) Forest management of floodplain sites in the northeastern United
5) Management of bottomland hardwoods 
6) Ecological communities of New York State 
7) Classification and evaluation of forest sites on the northern Cumberland
8) Classification and evaluation of forest sites on the Natchez Trace State
Forest, State Resort Park, and Wildlife Management Area in west
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
More info for the term: swamp
23 Eastern hemlock
24 Hemlock - yellow birch
25 Sugar maple - beech - yellow birch
26 Sugar maple - basswood
27 Sugar maple
37 Northern white-cedar
39 Black ash - American elm - red maple
60 Beech - sugar maple
61 River birch - sycamore
62 Silver maple - American elm
65 Pin oak - sweetgum
87 Sweetgum - yellow-poplar
91 Swamp chestnut oak - cherrybark oak
92 Sweetgum - willow oak
93 Sugarberry - American elm - green ash
94 Sycamore - sweetgum - American elm
95 Black willow
96 Overcup oak - water hickory
97 Atlantic white-cedar
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K098 Northern floodplain forest
K099 Maple - basswood forest
K100 Oak - hickory forest
K101 Elm - ash forest
K103 Mixed mesophytic forest
K106 Northern hardwoods
K112 Southern mixed forest
K113 Southern floodplain forest
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES15 Oak - hickory
FRES16 Oak - gum - cypress
FRES17 Elm - ash - cottonwood
FRES18 Maple - beech - birch
Habitat & Distribution
Open-grown American sycamores usually begin flowering in 6-7 years. Natural stands of sycamore usually produce appreciable numbers of seed at approximately 25 years; optimum seed production occurs from 50-200 years of age. Good seed crops are produced every 1-2 years. Sycamore seeds do not require any pretreatment for good germination. They do not germinate well in heavy litter or in deep shade or in temperatures outside of 59-86 o Fahrenheit (15-30 o C.).
Sycamore seedlings require direct sunlight for good growth and establishment, except perhaps on clay soil. One-year-old seedlings may reach 10 feet, and sprouts may reach 25 feet. The potentially great size of mature trees is correlated with exceptionally rapid growth, and maximum age probably does not exceed 250 years, although Smith (1952) notes that 500-600 may be the upper range.
acervulus of Discula coelomycetous anamorph of Apiognomonia errabunda is saprobic on fading, attached leaf of Platanus occidentalis
Remarks: season: 8-9
Other: major host/prey
Associated Forest Cover
In Sycamore-Sweetgurn-American Elm (Type 94), the chief associates are boxelder (Acer negundo), green ash (Fraxinus pennsylvanica), sugarberry (Celtis laevigata), silver maple (A. saccharinum), eastern cottonwood, black willow, water oak (Quercus nigra), Nuttall oak (Q. nuttallii), sweetgum, and river birch (Betula nigra). This type is found throughout the southern part of the range of sycamore, usually on the alluvial flood plains of major rivers. A Sycamore-Pecan-American Elm valiant type is found on river fronts in the Mississippi River Valley. A comprehensive survey of mixed hardwood species conducted in 14 Southeastern States by North Carolina State University showed that sycamore comprised 0.1 percent of the total basal area on wet flat sites, from 0.5 to 8.8 percent on various classes of bottom-land sites, 0.7 percent on lower slope coves, and 0.1 percent on upland slopes and ridges (26).
Other forest types with which sycamore grows are Black Ash-American Elm-Red Maple (Type 39) in the northern part of the sycamore range, Sugarberry-American Elm-Green Ash (Type 93) in the South, Sweetgum-Yellow-Poplar (Type 87) in the Atlantic Coastal Plain and Piedmont, and Black Willow (Type 95), which grows throughout the range of sycamore.
Sycamore is also an important tree in Cottonwood (Type 63), a valuable pioneer type, characteristic of fronts on all major streams in the South except in sloughs and swamps (21).
Diseases and Parasites
Diseases of sycamore have become more important with its increased culture in plantations. In the mid-1970's, potentially serious infection involving leaf scorch, dead branches, top dieback, and lethal cankers occurred in Illinois and adjacent States (22).
A 1973 survey of 26 plantations in Tennessee, Mississippi, Louisiana, and Alabama revealed leaf scorch, top dieback, and lethal bole cankers in four bottom-land plantations (9). In two progeny tests in Mississippi the same symptoms were evident, so severely in one test that it was a total loss within 5 years (5). The primary organism causing lethal bole cankers has not been established. A complex of organisms seems to be involved, but Ceratocystis fimbriata and Botryodiplodia theobromae are prime suspects. When seedlings were inoculated with either of these organisms by the bark-flap technique, cankers developed on the stem within 30 days; when 8-year-old trees were inoculated with Ceratocystis fimbriata, cankers appeared and some trees died within a year (19). Temperature also seems to be a factor (15,16,17). Acremonium diospyri has also been identified in trees displaying these symptoms.
Sycamore is susceptible to anthracnose, the same disease that attacks oaks (21). This fungus attacks in the spring and sometimes completely defoliates the trees. Severe attacks also kill twigs, and frequently cankers are formed up to 25 mm (1 in) in diameter. Usually, a second set of leaves is produced following defoliation and few trees die from an attack. Anthracnose may weaken a tree, however, making it susceptible to attack by other diseases. Heavy attacks by this disease also reduce radial and terminal growth. Sycamore is host to the eastern mistletoe (Phoradendron spp.) but damage usually is not serious.
Weather damage and damage caused by insects and disease are commonly confused. For example, anthracnose attacks are often mistaken for frost damage. Although low winter temperature may injure the cork cambium and cause the outer bark to be sloughed off, the health of the tree is not affected. Late spring frosts may kill sycamore buds over a wide area, and where this occurs, the damaged trees characteristically have long dead twigs with bushy masses of leaves around their bases by midsummer.
A limited study of sycamore shade trees following a sleet storm in west-central Illinois indicated that the tree is susceptible to ice damage (21). But in forest stands, it is seldom damaged by such storms.
Because it develops a widespread, strongly branched root system, sycamore is a windfirm tree. However, large sycamores are likely to develop windshake, a wood defect that reduces their value for lumber and other products.
Fire Management Considerations
In the Southeast, the usual fire season is fall; fire years occur
when the usual summer drought extends into autumn and early winter.
Most fires are accidentally caused by humans .
Prescribed fire is not recommended for southeastern bottomland forests
in which sycamore occurs; aside from damaging and killing trees, fire
reduces soil organic layers, leading to site degradation. Following
fire, weeds and vines flourish on exposed sites, increasing competition
with tree seedlings that may establish after fire [57,61].
Sycamore had a significantly lower proportion of its stem weight in bark
than any of the other species tested. In the soft hardwoods group (red
maple, sweetgum, sycamore, and yellow-poplar [Liriodendron tulipifera]),
sycamore had the highest average total-tree moisture content of any
species tested . A formula to estimate recoverable heat energy in
wood or bark fuels is available .
Plant Response to Fire
Sycamore is unlikely to be a major pioneer on burned sites. On
bottomlands, rapid growth of competing weeds and vines would reduce
sycamore establishment, and burned upland sites are usually too dry for
good seedling establishment. Only one published report of sycamore
seedlings on a burned site is available. In North Carolina, an oldfield
loblolly pine (Pinus taeda) stand experienced both surface and crown
fire. Sycamore seedlings were present in small numbers on the crown
fire plots, indicating that moisture and light conditions were
sufficient for sycamore seedling establishment . Top-killed
sycamore will sprout; it is unlikely, however, that a fire severe enough
to kill the aboveground portions will not also kill the shallow roots.
Immediate Effect of Fire
kill saplings and seedlings of all species. Larger trees are wounded by
fire; fire wounds act as vectors of disease, increasing rot and
decreasing plant vigor [57,61].
Tree with adventitious-bud root crown/soboliferous species root sucker
Secondary colonizer - off-site seed
Sycamore is a member of bottomland hardwood communities that do not
usually experience crown fires. Fire seasons occur approximately every
5 to 8 years; summer droughts extended into fall create conditions for
ground and surface fires which can cause damage and mortality.
Bottomland fires usually move rapidly along the surface, consuming
shrubs and herbs and usually killing all tree reproduction under about
10 years of age. Larger trees suffer bark scorch which causes wounds
that create points of entry for rots, stains, and insects; this results
in reduced vigor and delayed mortality. Under extreme conditions large
trees may be killed outright .
The only reported occurrence of sycamore in a historically
fire-maintained community is its presence in low numbers on a blue
ash-oak (Fraxinus quadrangulata-Quercus spp.) savanna in Kentucky. It
was not stated whether the presence of sycamore was synchronous with
frequent surface fires, or if it became established in this area since
the cessation of fire .
More info for the terms: climax, presence, swamp, tree
Facultative Seral Species
Sycamore is intolerant of shade. Seedling growth is greatly reduced in
deep shade (defined as 5 percent of full sunlight) . Sycamore
occurs in forest types that are pioneer, transitional, subclimax, and
Sycamore will pioneer on sand and gravel bars and other newly formed
land, often persisting through later seres, such as sugar maple (Acer
saccharum)-bitternut hickory (Carya cordiformis), particularly on wet
sites . It is an occasional pioneer on upland oldfield sites,
particularly in the central parts of its range. In Illinois, sycamore
was the most common tree species present in the seed rain or as
seedlings in local old fields .
In southern Illinois, 1- to 5-year-old sycamore seedlings were most
common on newly formed land, then on old fields, in cottonwood-willow
communities, and in soft mixed-hardwoods (elms, ashes, birches [Betula
spp.], silver maple, and red maple [Acer rubrum]); there were no
seedlings present in hard mixed-hardwood communities (oaks and
hickories) . Sycamore usually replaces willows (Salix spp.) and
eastern cottonwood (Populus deltoides). The sycamore-sweetgum-American
elm type usually succeeds cottonwood on river fronts, but may pioneer on
heavily cutover sites or old fields in bottomlands. This type may
persist as a subclimax type where repeated disturbances such as flooding
occur. It is usually succeeded by swamp chestnut oak (Quercus
michauxii)-cherrybark oak or sweetgum-willow oak (Liquidambar
styraciflua-Q. phellos) . In the North Carolina Piedmont, sycamore
and river birch (Betula nigra) usually replace alders (Alnus spp.) and
willows on small islands or spits in streams after the land becomes
stable and moderately well drained . Sycamore and river birch are
usually followed by elms (Ulmus spp.), ash (Fraxinus spp.) and red maple
. In Kentucky, an island that formed in 1913 was occupied by a pure
stand of eastern cottonwood 30 to 40 feet tall by 1922. Trees coming in
among the cottonwoods included sycamores .
The presence of sycamore in upland climax forests may be a function of
disturbance rather than a function of moisture or drainage regime; its
establishment in these woods may require larger disturbances than those
produced by single or multiple tree falls .
Sycamore is monoecious. Plantation-grown sycamores are usually sexually
mature in 6 to 7 years. Natural stands of sycamore usually produce
appreciable numbers of seed at approximately 25 years; optimum seed
production occurs from 50 to 200 years of age. Seed production is not
dependable from trees over 250 years old. Good seed crops are produced
every 1 to 2 years . Sycamore seeds are dispersed by wind and water
. They have a relatively rapid rate of descent for light seeds; the
estimated lateral travel distance in a 6 mile per hour (10 km/hr) breeze
is 223.7 feet (62.8 m) . Since seed dispersal occurs at a time of
year when water levels are declining after spring floods, water
dispersal often results in seed deposition on muddy flats that are
highly conducive to germination [44,83].
Sycamore seeds do not require any pretreatment for good germination .
They do require very moist conditions for good germination and are
tolerant of inundation . Soaking seeds in water for up to 32 days
did not reduce germination rates; the seeds did not germinate during the
soaking period . Sycamore seeds germinated at a significantly
higher percentage in light than in dark ; they do not germinate well
in heavy litter or in deep shade . Sycamore seeds did not germinate
in laboratory tests at temperatures lower than 59 degrees Fahrenheit (15
deg C); they germinated well at temperatures between 59 and 86 degrees
Fahrenheit (15-30 deg C), with maximum emergence at 68 degrees
Fahrenheit (20 deg C) in the wetter part of a moisture gradient .
Sycamore seedlings require direct sunlight for good growth and
establishment . At the end of their first year, sycamore seedlings
on clay soil showed better height growth in partial shade than in full
sun. On alluvial soil or loess, height growth was better in full sun
. Seedling roots penetrate the soil quickly and grow deeper in loess
soils than in alluvial or clay soils .
Young sycamore stems sprout readily from the stump; sycamore is not a
vigorous epicormic sprouter. Sycamore can be vegetatively propagated by
Growth Form (according to Raunkiær Life-form classification)
Reaction to Competition
In the Piedmont of North Carolina, sycamore and birch tend to replace pioneer trees like alder and willow on small islands or spits in streams after this land becomes stable and drained (21). Sycamore and birch, in turn, are usually succeeded by elm (Ulmus spp.), ash, and red maple. It was found, however, that sycamore seedlings grown under controlled light were at least as tolerant as American and winged elm (U. americana and U. alata) on the basis of observed height growth and top-to-root ratios (21).
On sand and gravel bars and on flood plains in Missouri, sycamore is a pioneer tree that persists throughout later successional stages in the sugar maple-bitternut hickory variant of Sugar Maple (Type 27) (21). This variant grows on wet sites where the soils are usually neutral to calcareous.
Sycamore is also found in forest types that are pioneer, transitional, subclimax, and climax in the succession. On moist or wet sites in subclimax, deciduous forests it grows in association with oaks, black walnut (Juglans nigra), hackberry (Celtis occidentalis), sweetgum, cottonwood, and willow. It seems able to maintain itself in some of these subclimax and climax forest types because of its rapid growth and longevity. Usually it maintains a position in subclimax types only when they are in bottom land or other moist situations. On dryer sites sycamore usually has only pioneer or transitional status and is eventually replaced by tolerant trees or trees having less demanding moisture requirements.
Epicormic sprouting is not a serious problem in sycamore. Pruning widely spaced, open-grown natural trees 9 years old did not result in serious sprouting. In a Georgia thinning study, epicormic branching of sycamore was appreciable only where basal area was reduced to less than 18.4 m²/ha (80 ft²/acre), which was two-thirds or less of the original basal area. Heavier thinning resulted in 14 to 15 epicormic branches per tree (21).
Life History and Behavior
More info for the term: tree
Sycamore flowers appear in May in the northern parts of its range, and
as early as late March in the South. Late spring frosts will kill
flowers, leaves, and twigs . The fruits ripen from September to
October or November, and usually remain on the tree over winter,
breaking up or falling off the following spring from February through
Slips or cuttings made from young, fast-growing stems root readily and may be used for propagation. Healthier top growth has been noted on cuttings that were made closer to the root collars than other parts of the stem, and fall-planted cuttings grew better than those planted in the spring (21). Cuttings from mature trees cannot be rooted by conventional methods, but a modified air-layering technique consisting of girdling and application of growth-promoting hormones on the tree before the cuttings are taken has been successful (10).
Germination is epigeal and is affected by light. In tests made at temperatures ranging between 23° to 27° C (73° to 810 F), the mean germination under artificial light was 17.5 percent and only 3.1 percent in the dark (21). Seeds failed to germinate in the river-bottom soils of southern Illinois wherever litter was more than 2 inches deep. Sycamore seedlings must have direct light to survive; under favorable conditions they develop a strong, spreading root system and grow rapidly, as much as 91 to 122 cm (36 to 48 in) in height the first year. Roots also penetrate deeper in loess soil than in alluvial or clay soils.
Seed Production and Dissemination
Sycamore seeds average about 441,000/kg (200,000/lb) and are dispersed from February through May of the spring following ripening. As the seed balls break up, the seeds are released and float down slowly. The hairs act as parachutes, and the seeds are widely scattered by the wind. Several birds feed on the seeds and also may disseminate them to a minor extent. Moreover, the seeds are carried by water and are often deposited on mudflats or sandbars where conditions are usually favorable for germination (21).
Flowering and Fruiting
Growth and Yield
State Seedlings and saplings Pole-size trees Sawtimber cm cm cm Illinois 8.2 -- 8.6 Indiana 8.9 6.6 6.4 Kentucky 6.0 6.9 8.1 Missouri 6.0 7.8 9.1 Ohio 7.4 3.6 6.0 in in in Illinois 3.2 -- 3.4 Indiana 3.5 2.6 2.5 Kentucky 2.4 2.7 3.2 Missouri 2.4 3.1 3.6 Ohio 2.9 1.4 2.4
These are average growth rates for a range of sites and should not be considered as indicative of growth that might be expected on either poor or good sites.
Sycamore in a 17-year-old North Carolina stand had an average d.b.h. of more than 23 cm (9 in) and an average height of 21.3 in (70 ft). There was a total volume of 126 m³/ha (1,800 ft³/acre) or 32.3 m³/ha (2,310 fbm/acre) of sawtimber plus 75.6 m³/ha (1,080 ft³/acre) of pulpwood. This stand was expected to have a volume of 140 m³/ha (10,000 fbm/acre) of sawtimber by age 22 (21). This figure is slightly higher than average yield for mixed hardwoods in the southeastern United States. Annual hardwood yields in the major bottom-land type (where sycamore made up 8.8 percent of the stand) were found to average about 4.0 m³/ha (57 ft³/acre) in stands from 20 to 60 years old (26).
The potential for plantation-grown sycamore seems much higher than the yields for natural stands. A survey conducted by North Carolina State University found that annual plantation yields ranged from 7.7 m³/ha (110 ft³/acre) at age 5, to 14.3 m³/ha (204 ft³/acre) at age 25 (25). Most of the plantations in this survey were not cultivated to optimum intensity after establishment and in all likelihood do not represent the ultimate or even the practical maximum attainable yield.
Annual yield at age 11 in a sycamore plantation in central Georgia was 17.2 m³/ha (245 ft³ /acre). Average d.b.h. was 15 cm (6 in) and average height was 19 in (63 ft) (2). The highest yields for sycamore under intensive culture were recorded on a "creek bottom-land site" in the Georgia Piedmont (14) and in the lower Mississippi River Valley for 4-year coppice rotation following 3 or 4 years in seedling rotation (6). Annual yields were from 24 to 32 m³/ha (343 ft³/acre). This yield is comparable to maximum yields obtained with other fast-growing genera such as Populus and Alnus that have been grown on "mini-rotations" (4).
The American sycamore grows to a larger diameter than any other North American hardwood. Trees are on record that exceeded 305 cm (120 in) in d.b.h. and 43 ni (140 ft) in height (21). An individual tree in Indiana was 320 cm (126 in) in diameter at 1.2 in (4 ft) above the ground and 51 ni (168 ft) tall (21).
Open-grown sycamores have a large irregular crown that may spread to 30 ni (100 ft) in diameter. Under forest conditions the tree has a relatively small crown and a long, slightly tapered bole that may be clear of branches for 20 or 25 m (70 or 80 ft).
Molecular Biology and Genetics
Geographic variation in sycamore is extensive, and, noted in many other widely distributed species, trees of southern origin have a potential for faster growth than trees of more northern origin when planted near or slightly north of their point of origin (8,13,24,29,31).
Sycamore is unique among North American tree species in displaying a strong north-south gradient in resistance to a killing stem canker disease. In two progeny tests of half-sib families selected along the Mississippi and Chattahoochie Rivers, families of northern origin (Missouri and northern Georgia) were attacked much more severely than were families from farther south (southern Georgia and Louisiana) (5).
Two varieties of sycamore have been named in addition to the typical variety. P. occidentalis var. glabrata is common in western Texas and Mexico but is considered by some taxonomists to be synonymous with the typical variety. P. occidentalis var. attenuata is apparently intermixed with the typical variety, but its status is in need of clarification. The London plane of the Old World, P. x acerifolia, is considered a collection of advanced generation hybrids and backcrosses between P. orientalis and P. occidentalis (12). London plane is an important street tree in cities of the United States and Europe because of its resistance to diseases and especially the air pollution found in the urban environment.
Barcode data: Platanus occidentalis
Statistics of barcoding coverage: Platanus occidentalis
Public Records: 5
Specimens with Barcodes: 9
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
concern-possibly extirpated .
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
Sycamore is a valuable timber species that can be regenerated from
natural seed sources, by planting, or by coppice systems.
Seed: Sycamore invades bottomland old fields when adequate seed
sources are present [3,59]. It oftens seeds in on clearcuts; good
initial establishment from natural seed sources requires some site
preparation . Its potential for establishment from direct seeding
is unknown .
Plantation: Sycamore usually shows good initial capture of planting
sites . Sycamores interplanted with herbaceous legumes were larger
than control plants 6 years after legume establishment . On mined
sites interplanting sycamore with the nitrogen-fixing European black
alder (Alnus glutinosa) doubled sycamore height and diameter growth over
that of control plants . Site characteristics, rather than site
preparation method, had the most pronounced effect on sycamore height
growth . However, Hunt and Cleveland  reported sycamore growing
on disc-cultivated sites showed better growth than with other
treatments. Sycamore does not establish well in dense herb or shrub
cover . Clatterbuck and Burkhardt  reported on the effects of
various mixtures and spacings for cherrybark oak (Quercus falcata) and
sycamore plantations in Arkansas.
Coppice: For short-rotation intensive culture systems, sycamore yield
is influenced by site, fertilizer, spacing, and rotation . Sycamore
has good coppice regeneration potential although it may not be
sustainable over many rotations. Geyer  reported that sycamore died
after two coppice harvests in Kansas. A high percentage of stumps
sprout, regardless of stump size or time of harvest. However, dormant
season cuts produce larger and heavier sprout clumps than cuts during
the growing season [5,78].
Insects and Diseases: Natural stands of sycamore have few lethal
diseases ; disease problems occur mostly in plantations. Important
diseases include anthracnose and eastern mistletoe (Phoradendron spp.)
. There have been some reports of a potentially serious disease of
sycamore in Illinois and adjacent states, and possibly spreading to
Tennessee, Mississippi, Louisiana, and Alabama. This disease has been
attributed to attacks by various organisms on environmentally stressed
trees; it is not attributed to a single cause . There are no
insects of economic importance in natural stands, although problems with
insects occur in landscaping trees .
Large sycamores sometimes develop wind shake, a wood defect that reduces
its economic value . Sycamore is susceptible to ice damage
; of six trees examined after an ice/sleet storm in Missouri and
Illinois, only one escaped major damage .
Under powerlines, sycamore regrowth was appreciably reduced with
pressure-injected malic hydrazide or daminozide .
Cultivars, improved and selected materials (and area of origin)
These plant materials are readily available from commercial sources. Contact your local Natural Resources Conservation Service (formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government.” The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”
American sycamore can be regenerated from natural seed sources, by planting, or by stump and root sprouting. On "silvicultural biomass farms" aimed at maximum fiber production, fertilization is usually necessary, especially with rotations shorter than 5 years. Sycamores in managed plantations interplanted with legumes or other nitrogen-fixing species were larger than control plants 6 years after establishment of the nitrogen fixers. Sycamore has good coppice regeneration potential, although it has been reported that trees died after two successive harvests. A high percentage of stumps sprout, regardless of stump size or time of harvest, although larger and heavier sprouts are produced from dormant season cuts (vs. growing season).
Significant diseases and insect problems occur in managed plantations and landscaping trees of American sycamore but are largely absent from natural stands. Important problems include anthracnose and eastern mistletoe (Phoradendron spp.).
Prescribed fire is not recommended for bottomland forests in which sycamore occurs. Bottomland fires usually move rapidly along the surface, consuming shrubs and herbs and usually killing saplings and seedlings of all species. Larger trees suffer bark wounds that create points of entry for rots, stains, and insects. Under extreme conditions, large trees may be killed outright. Fire also reduces soil organic layers, leading to site degradation.
Relevance to Humans and Ecosystems
Other uses and values
Sycamore is planted as a street tree , although it is highly
susceptible to ozone damage  and is susceptible to foliar injury and
reduced growth when exposed to salt spray . The London plane tree
is more resistant to air pollutants and is more commonly planted as a
street tree .
Sycamore has been planted in shelterbelts .
Value for rehabilitation of disturbed sites
Sycamore occurs naturally on disturbed sites if there is sufficient
moisture for seedling establishment. It occasionally occurs in mostly
pure, well-stocked stands on naturally regenerated strip-mined lands in
the central states. In Missouri, it is often found in pure stands or in
mixtures with other hardwoods that pioneer on spoil banks. In Alabama
and Tennessee, waterway disposal sites (material removed from stream
channels) seeded with grass mixtures were invaded by sycamore . In
Tennessee, channelization projects resulting in degrading streambanks
were colonized by sycamores during the early recovery period .
Sycamore saplings were present in small numbers on unreclaimed limestone
quarries in Oklahoma .
Between 1928 and 1975, sycamore was one of the 10 most commonly planted
hardwoods on surface-mined soils in Indiana . Sycamore is
recommended for planting on all types of strip-mined land in many
northeastern and central states . In Florida, sycamore was planted
on a phosphate mine site for a wetland reclamation project . In
Tennessee, beaver impoundments were drained and planted with sycamore;
sycamore was chosen for its ability to tolerate saturated soils .
Importance to Livestock and Wildlife
eaten by some birds including the purple finch [82,84], goldfinch,
chickadees, and dark-eyed junco , and by muskrat, beaver, and
squirrels [13,76,82,84]. Sycamore is rated as medium in suitability for
waterfowl habitat and low in suitability as deer or turkey food .
Carey and Gill  rated sycamore as only fair (their lowest rating)
for wildlife use. In Arkansas, sycamore is of minor importance as deer
browse . As sycamores age, they may develop hollow trunks which
provide shelter for a number of wildlife species; some large, old
individuals have formed cavities large enough to be used as dens by
black bear . Cavity nesting birds include the barred owl ,
eastern screech-owl, great crested flycatcher , and chimney swift
. Wood duck use sycamores as nest trees .
The bottomland forests in which sycamore occurs are very important
wildlife habitat, sheltering numerous animal species including wood
duck, other waterfowl, upland game birds, and deer . In Indiana,
riparian forests in which sycamore occurs are important habitat for the
endangered Indiana bat, which uses these areas for nursery colonies
Wood Products Value
Sycamore is a valuable timber tree; its wood is hard, with a twisted and
coarse grain, but not very strong [13,30,76]. It is used for furniture,
interior trim, boxes, pulpwood, and particle and fiber board [13,30]. Carey
and Gill  rated sycamore as only fair (their lowest rating) for
Sycamore is planted in short-rotation intensive culture systems for use
as fuel or pulp [72,78].
follows: 25 percent dry matter, 13.7 percent crude protein, and 67
percent total digestible nutrients . Foliage samples were 18.2
percent lignin, 2.67 percent calcium, 0.38 percent magnesium, 0.12
percent phosphorus, and 1.65 percent potassium .
Some plantations have been established at very close spacing and are being reproduced by coppice on short rotations in a silvicultural scheme aimed at maximum fiber production. This kind of culture has been termed "short-rotation forestry" (27) or "silvicultural biomass farms" (11). The entire aboveground portion of the plant is harvested and estimates of annual biomass production in parts of the United States range from 11.2 to 29.1 dry ton equivalents/ha (5 to 13 dry ton equivalents/acre) at rotations of 4 to 10 years (4).
Nutrient drain on the site is greater than with conventional long rotation management (1,32) and fertilization is usually necessary, especially with rotations shorter than 5 years (28).
In spite of the high initial cost, one analysis in the Coastal Plain of Virginia and North Carolina estimated that over a 36-year period (three 12-year coppice rotations) total yield of four hardwood species including sycamore would be increased at least 50 percent over natural stands at one-third the cost of a system of natural regeneration (20).
Industry: American sycamore is grown in short-rotation plantations primarily for pulp and it also is used for rough lumber. The heavy, close-grained wood is difficult to split and work because of interlocking fibers. It has been used for butcher's blocks, furniture, veneer and interior trim, boxes and crates, flooring, and particle and fiberboard.
Conservation: American sycamore is a good planting where a large, fast-growing tree is desired. Negative features are the relatively weak limbs (susceptible to wind and ice damage) and the large leaves that decay slowly after falling. The huge size quickly attained by these trees is often underestimated. The London planetree, Platanus hybrida Brot. (= Platanus acerifolia (Ait.) Willd.), is widely planted as a street tree, probably due to its disease resistance and tolerance of air pollution (American sycamore is susceptible to ozone damage). The London plane is a hybrid between American sycamore and oriental plane (P. orientalis) and perhaps includes a number of backcrosses.
American sycamore is recommended for planting on all types of strip-mined land, and it is useful in rehabilitation of various sites with saturated soils. It is often a natural early colonizer of disturbed sites such as old fields, spoil banks, streambanks degraded by channelization, and waterway disposal sites.
Ethnobotanic: Native Americans used sycamore for a variety of medicinal purposes, including cold and cough remedies, as well as dietary, dermatological, gynecological, respiratory, and gastrointestinal aids.
Platanus occidentalis, also known as American sycamore, American planetree, occidental plane, and buttonwood, is one of the species of Platanus native to North America. It is usually called sycamore in North America, a name which can refer to other types of tree in other parts of the world.
An American sycamore tree can often be easily distinguished from other trees by its mottled exfoliating bark which flakes off in great irregular masses, leaving the surface mottled, and greenish-white, gray and brown. The bark of all trees has to yield to a growing trunk by stretching, splitting, or infilling; the sycamore shows the process more openly than many other trees. The explanation is found in the rigid texture of the bark tissue which lacks the elasticity of the bark of some other trees, so it is incapable of stretching to accommodate the growth of the wood underneath, so the tree sloughs it off.
A sycamore can grow to massive proportions, typically reaching up to 30 to 40 m (98 to 131 ft) high and 1.5 to 2 m (4.9 to 6.6 ft) in diameter when grown in deep soils. The largest of the species have been measured to 51 m (167 ft), and nearly 4 m (13 ft) in diameter. Larger specimens were recorded in historical times. In 1770, at Point Pleasant, WV near the junction of the Kanawha and Ohio Rivers, George Washington recorded in his journal a sycamore measuring 13.67 m (44 ft 10 in) in circumference at 91 cm (3 ft) from the ground.
The sycamore tree is often divided near the ground into several secondary trunks, very free from branches. Spreading limbs at the top make an irregular, open head. Roots are fibrous. The trunks of large trees are often hollow.
Another peculiarity is the way the leaves grow sticky, green buds. In early August, most trees in general will have—nestled in the axils of their leaves—the tiny forming bud which will produce the leaves of the coming year. The sycamore branch apparently has no such buds. Instead there is an enlargement of the petiole which encloses the bud in a tight-fitting case at the base of the petiole.
- Bark: Dark reddish brown, broken into oblong plate-like scales; higher on the tree, it is smooth and light gray; separates freely into thin plates which peel off and leave the surface pale yellow, or white, or greenish. Branchlets at first pale green, coated with thick pale tomentum, later dark green and smooth, finally become light gray or light reddish brown.
- Wood: Light brown, tinged with red; heavy, weak, difficult to split. Largely used for furniture and interior finish of houses, butcher's blocks. Specific gravity, 0.5678; relative density, 0.53724 g/cm3 (33.539 lb/cu ft).
- Winter buds: Large, stinky, sticky, green, and three-scaled, they form in summer within the petiole of the full grown leaf. The inner scales enlarge with the growing shake. There is no terminal bud.
- Leaves: Alternate, palmately nerved, broadly ovate or orbicular, 10 to 23 cm (4 to 9 in) inches long, truncate or cordate or wedge-shaped at base, decurrent on the petiole. Three to five-lobed by broad shallow sinuses rounded in the bottom; lobes acuminate, toothed, or entire, or undulate. They come out of the bud plicate, pale green coated with pale tomentum; when full grown are bright yellow green above, paler beneath. In autumn they turn brown and wither before falling. Petioles long, abruptly enlarged at base and inclosing the buds. Stipules with spreading, toothed borders, conspicuous on young shoots, caducous.
- Flowers: May, with the leaves; monoecious, borne in dense heads. Staminate and pistillate heads on separate peduncles. Staminate heads dark red, on axillary peduncles; pistillate heads light green tinged with red, on longer terminal peduncles. Calyx of staminate flowers three to six tiny scale-like sepals, slightly united at the base, half as long as the pointed petals. Of pistillate flowers three to six, usually four, rounded sepals, much shorter than the acute petals. Corolla of three to six thin scale-like petals.
- Stamens: In staminate flowers as many of the divisions of the calyx and opposite to them; filaments short; anthers elongated, two-celled; cells opening by lateral slits; connectives hairy.
- Pistil: Ovary superior, one-celled, sessile, ovate-oblong, surrounded at base by long, jointed, pale hairs; styles long, incurved, red, stigmatic, ovules one or two.
- Fruit: Brown heads, solitary or rarely clustered, 2.5 cm (1 in) in diameter, hanging on slender stems three to six inches long; persistent through the winter. These heads are composed of achenes about two-thirds of an inch in length. October.
In its native range, it is often found in riparian and wetland areas. The range extends from Iowa to Ontario and Maine in the north, Nebraska in the west, and south to Texas and Florida. Closely related species (see Platanus) occur in Mexico and the southwestern states of the U.S. It is sometimes grown for timber, and has become naturalized in some areas outside its native range. It can be found growing successfully in Bismarck, North Dakota, and it is sold as far south as Okeechobee. The American sycamore is also well adapted to life in Argentina and Australia and is quite widespread across the Australian continent especially in the cooler southern states such as Victoria and New South Wales.
The sycamore is able to endure a big city environment and was formerly extensively planted as a shade tree, but due to the defacing effects of anthracnose it has been largely usurped in this function by the resistant London plane.
Its wood has been used extensively for butcher’s blocks. It has been used for boxes and crates; although coarse-grained and difficult to work, it has also been used to make furniture, siding, and musical instruments.
Pests and diseases
The American sycamore is a favored food plant of the pest sycamore leaf beetle.
American sycamore is susceptible to Plane anthracnose disease (Apiognomonia veneta, syn. Gnomonia platani), an introduced fungus found naturally on the Oriental plane P. orientalis, which has evolved considerable resistance to the disease. Although rarely killed or even seriously harmed, American sycamore is commonly partially defoliated by the disease, rendering it unsightly as a specimen tree.
Sometimes mistaken for frost damage, the disease manifests in early spring, wilting new leaves and causing mature leaves to turn brown along the veins. Infected leaves typically shrivel and fall, so that by summer the tree is regrowing its foliage. Cankers form on twigs and branches near infected leaves, serving to spread the disease by spore production and also weakening the tree. Because cankers restrict the flow of nutrients, twigs and branches afflicted by cankers eventually die. Witch's broom is a symptom reflecting the cycle of twigs dying.
As a result of the fungus' damage, American sycamore is often avoided as a landscape tree, and the more resistant London plane (P. × hispanica; hybrid P. occidentalis × P. orientalis) planted instead.
The sycamore made up a large part of the forests of Greenland and Arctic America during the Cretaceous and Tertiary periods. It once grew abundantly in central Europe, from which it has now disappeared. It was brought to Europe early in the 17th century.
- Buttonball Tree, an American sycamore, said to be the largest on the East Coast, located in Sunderland, Massachusetts
- Pinchot Sycamore, an American sycamore that is the largest tree in Connecticut
The sycamore tree is mentioned in the famous song "Dream a Little Dream of Me" (in its 4th line), "Birds singing in the sycamore tree."
- Keeler, Harriet L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scribner's Sons. pp. 263–268.
- Dale Luthringer (2007-03-22). "Historical sycamore dimensions". Newsgroup: Native Tree Society Eastern Native Tree Society. Retrieved 2009-11-16.
- "2012 Register of Champion Trees". NDSU–North Dakota Forest Service. Retrieved 18 April 2013.
- Grimm, William C. (1983). The Illustrated Book of Trees. Harrisburg, PA: Stackpole Books. pp. 257–259. ISBN 0-8117-2220-1.
- Devine, Warren D.; Tyler, Donald D.; Mullen, Michael D.; Houston, Allan E.; Joslin, John D.; Hodges, Donald G.; Tolbert, Virginia R.; Walsh, Marie E. (May 2006). "Conversion from an American sycamore (Platanus occidentalis L.) biomass crop to a no-till corn (Zea mays L.) system: Crop yields and management implications". Soil and Tillage Research 87 (1): 101–111. doi:10.1016/j.still.2005.03.006.
- Swift, C.E. (October 2011). "Sycamore Anthracnose". Colorado State University Extension. Retrieved 18 April 2013.
- Olmert, Michael (1996). Milton's Teeth and Ovid's Umbrella: Curiouser & Curiouser Adventures in History. New York: Simon & Schuster. p. 217. ISBN 0-684-80164-7.
The cultivated London plane-tree [ Platanus × acerifolia (Aiton) Willdenow, Platanus hybrida Broterius] will key here. It is distinguished by the lobes of its larger leaves being somewhat longer and narrower (often longer than wide), the fruiting heads one or two on each rachis, and the bark often somewhat greener. Many cultivars are available, some with deeper lobed or variegated leaves or with upright habit (F. S. Santamour Jr. 1986). It is often planted in cities because it is exceptionally well adapted as a street tree. Apparently it has not escaped in North America, where it is mostly seed-propagated. It is only occasionally reported as naturalized in Europe; there it is clonally propagated and is variously reported to be fertile or sterile. Reputedly, it is a hybrid of P . occidentalis with the Eurasian P . orientalis Linnaeus. Such a hybrid has been synthesized (F. S. Santamour Jr. 1972b).
Native Americans used Platanus occidentalis for a variety of medicinal purposes, including cold and cough remedies, as well as dietary, dermatological, gynecological, respiratory, and gastrointestinal aids (D. E. Moerman 1986).
Names and Taxonomy
The currently accepted scientific name for sycamore is Platanus
occidentalis L. (Platanaceae) [13,35,48,50]. There are no accepted
The London plane tree (P. xacerifolia [Ait.] Willd.) is a hybrid of
Oriental plane (P. orientalis) and sycamore and perhaps includes a
number of backcrosses [50,78].
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