A number of Sycamore trees can be seen along the east bank of the Kentucky River all along our nature trail and around the area of the beaver dam/pond. The Sycamore is easy to spot the brown peeling bark showing a white trunk and the very large leaves.

Common Name:  Sycamore

Scientific Name:  Platanus occidentalis

A.K.A:
American Plane Tree, Buttonwood,
Lacewood

 

An American sycamore tree is easily recognized by its mottled exfoliating bark. The bark of all trees has to yield to a growing trunk; in the case of trees such as the Silver Maple and the Shagbark Hickory the process is not hidden, but the Sycamore shows the process of exfoliation more openly than any other tree. The bark of the trunk and larger limbs flakes off in great irregular masses, leaving the surface mottled, and greenish-white, gray and brown. Sometimes the smaller limbs look as if whitewashed. The explanation is found in the rigid texture of the bark tissue, which lacks the elasticity common to the bark of other trees, so it is incapable of stretching to accommodate the growth of the wood underneath and the tree sloughs it off.

A sycamore can grow to massive proportions, typically reaching up to 30 to 40 meters (aprox. 98' to 131') high and 1.5 to 2 meters (4'11" to 6'6") in diameter when grown in deep soils. The largest of the species have been measured to 51 meters (167'), and nearly 4 meters (about 13'1") in diameter. Historical specimens over 5 meters (about 16'5") thick have been reported.

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.

The Characteristic Bark of an American Sycamore

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. Sp. gr., 0.5678; weight of cu. ft., 35.39 lbs.

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, four to nine 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, an inch in diameter, hanging on slender stems three to six inches long; persistent through the winter. These heads are composed of akenes about two-thirds of an inch in length.

The fruit of the sycamore is a woody ball that ripens in October and persists through the winter, when it breaks up into many small seeds.

Each seed has a tuft of brown hairs that allows the wind to scatter it.

Sycamores have both male and female flowers, so every tree has fruits on it.

Indeed, the sycamore prefers deep river-bottom soils.  In the Mississippi and Ohio River valleys, they may attain spectacular size - up to 175 feet tall and 14 feet in diameter!  Individual trees may live over 500 years.

The wood of the sycamore is hard and coarse-grained and often has a flaky appearance, which led to its nickname of lacewood.  It gets used in cabinets, furniture, boxes and barrels.  The native Americans would use the whole trunk of a tree to make dugout canoes.  One of these was reported to have been 65 feet long and weighed 4 1/2 tons!

The name of the tree derives from the Greek sukomoros, which is a type of fig tree native to the Mediterranean.  Evidently there is some similarity in the leaves, and this led to the transference of the name.

In cities, the London Plane Tree (Platanus x hybrida) is frequently used as a street tree.  It is a cross between the American Sycamore and the Oriental Sycamore (Platanus orientalis).   It is similar in appearance to the sycamore, but has smaller leaves and its fruits appear in pairs rather than singly.  It is used in preference to the native sycamore because it is more resistant to a fungus called anthracnose blight (Gnomonia platani).    The fungus attacks young twigs and leaves in the spring, causing them to die and fall off.  Repeated attacks on a branch produce clusters of small twigs called witches brooms.

Not only raccoons, but also opossums, squirrels and wood ducks make homes in cavities in the trunk and major branches.   The open branching pattern and sheer size of older sycamores creates good locations for Great Blue Heron nests.  As a long-lived member of the riparian forest community in the eastern US, sycamores offer many opportunities to the native animals as well as an eye-catching accent on the landscape.

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