Liriodendron tulipifera

Liriodendron tulipifera
Liriodendron tulipifera
Morton Arboretum acc. 500-67*21
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Magnoliids
Order: Magnoliales
Family: Magnoliaceae
Genus: Liriodendron
Species: L. tulipifera
Binomial name
Liriodendron tulipifera
L.
Range

Liriodendron tulipifera, commonly known as the tulip tree, American tulip tree, tuliptree, tulip poplar or yellow poplar, is the Western Hemisphere representative of the two-species Liriodendron genus and the tallest eastern hardwood. It is native to eastern North America from Southern Ontario and Illinois eastward across southern New England and south to central Florida and Louisiana. It can grow to more than 50 m (165 feet) in virgin cove forests of the Appalachian Mountains, often with no limbs until it reaches 25–30 m (80–100 feet) in height, making it a very valuable timber tree. It is fast-growing, without the common problems of weak wood strength and short lifespan often seen in fast-growing species. April marks the start of the flowering period in the southern USA (except as noted below); trees at the northern limit of cultivation begin to flower in June. The flowers are pale green or yellow (rarely white), with an orange band on the tepals; they yield large quantities of nectar. The tulip tree is the state tree of Indiana, Kentucky and Tennessee.

Contents

Description

The tulip tree is one of the largest of the native trees of the eastern United States, known to reach the height of 190 feet (58 m), with a trunk 10 feet (3 m) in diameter; its ordinary height is 70 feet (21 m) to 100 feet (30 m). It prefers deep, rich, and rather moist soil; it is common, though not abundant, nor is it solitary. Its roots are fleshy. Growth is fairly rapid, and the typical form of its head is conical.[1]

The bark is brown, and furrowed. The branchlets are smooth, and lustrous, initially reddish, maturing to dark gray, and finally brown. Aromatic and bitter. The wood is light yellow to brown, and the sapwood creamy white; light, soft, brittle, close, straight-grained. Sp. gr., 0.4230; weight of cu. ft., 26.36 lbs.

The alternate leaves are simple, pinnately veined, measuring five to six inches long and wide. They have four lobes, and are heart-shaped or truncate or slightly wedge-shaped at base, entire, and the apex cut across at a shallow angle, making the upper part of the leaf look square; midrib and primary veins prominent. They come out of the bud recurved by the bending down of the petiole near the middle bringing the apex of the folded leaf to the base of the bud, light green, when full grown are bright green, smooth and shining above, paler green beneath, with downy veins. In autumn they turn a clear, bright yellow. Petiole long, slender, angled.

Liriodendron tulipifera 'Mediopictum' leaves (autumn).
Liriodendron tulipifera flower

A description from Our native trees and how to identify them by Harriet Louise Keeler[1]:

The leaves are of unusual shape and develop in a most peculiar and characteristic manner. The leaf-buds are composed of scales as is usual, and these scales grow with the growing shoot. In this respect the buds do not differ from those of many other trees, but what is peculiar is that each pair of scales develops so as to form an oval envelope which contains the young leaf and protects it against changing temperatures until it is strong enough to sustain them without injury. When it has reached that stage the bracts separate, the tiny leaf comes out carefully folded along the line of the midrib, opens as it matures, and until it becomes full grown the bracts do duty as stipules, becoming an inch or more in length before they fall. The leaf is unique in shape, its apex is cut off at the end in a way peculiarly its own, the petioles are long, angled, and so poised that the leaves flutter independently, and their glossy surfaces so catch and toss the light that the effect of the foliage as a whole is much brighter than it otherwise would be.

The flowers are large, brilliant, and on detached trees numerous. Their color is greenish yellow with dashes of red and orange, and their resemblance to a tulip very marked. They do not droop from the spray but sit erect. The fruit is a cone two to three inches long, made of a great number of thin narrow scales attached to a common axis. These scales are each a carpel surrounded by a thin membranous ring. Each cone contains sixty or seventy of these scales, of which only a few are productive. These fruit cones remain on the tree in varied states of dilapidation throughout the winter.

Distribution

Found sparingly in New England, it is abundant on the southern shore of Lake Erie and westward to Illinois. It extends south to north Florida, and is rare west of the Mississippi River. Its finest development is in the Southern Appalachian mountains, where trees may exceed 170 feet in height.

Ecology

Tuliptree unfolding leaves

Liriodendron tulipifera is generally considered to be shade-intolerant species that is most commonly associated with the first century of forest succession. In Appalachian forests, it is a dominant species during the 50–150 years of succession, but is absent or rare in stands of trees 500 years or older. On mesic, fertile soils, it often forms pure or nearly pure stands. It can and does persist in older forests when there is sufficient disturbance to generate large enough gaps for regeneration.[2]

All young tulip trees and most mature specimens are intolerant of prolonged inundation; however, a coastal plain swamp ecotype in the southeastern United States is relatively flood-tolerant.[3] This ecotype is recognized by its blunt-lobed leaves, which may have a red tint. Parts of east-central Florida near Orlando have an ecotype with similar-looking leaves; it flowers much earlier (usually in March, although flowering can begin in late January) than other types. This east central Florida ecotype seems to have the best ability to tolerate very wet conditions, where it may grow short pencil-like root structures (pneumatophores) similar to those produced by other swamp trees in warm climates. Some individuals retain their leaves all year unless a hard frost strikes.

Liriodendron tulipifera produces a large amount of seed, which is dispersed by wind. The seeds typically travel a distance equal to 4-5 times the height of the tree, and remain viable for 4–7 years. The seeds are not one of the most important food sources for wildlife, but they are eaten by a number of birds and mammals.[4]

Vines, especially wild grapevines are known to be extremely damaging to young trees of this species. Vines are damaging both due to blocking out solar radiation, and increasing weight on limbs which can lead to bending of the trunk and/or breaking of limbs.[4]

Taxonomy and naming

Originally described by Linnaeus, Liriodendron tulipifera is one of two species in the genus Liriodendron in the magnolia family. It is also called the tuliptree Magnolia, or sometimes confusingly, by the lumber industry, as the tulip poplar or yellow poplar, although it is unrelated to the poplars of the family Salicaceae.

The tulip tree has impressed itself upon popular attention in many ways, and consequently has many common names. In areas near the Mississippi River it is called a poplar largely because of the fluttering habits of its leaves, in which it resembles trees of that genus. The color of its wood gives it the name Whitewood. Native Americans so habitually made their dugout canoes of its trunk that the early settlers west of the Appalachian Mountains called it Canoewood. The resemblance of its flowers to tulips named it the Tulip-tree.[1]

Cultivation and use

The tree grows readily from seeds, which should be sown in a fine soft mould, and in a cool and shady situation. If sown in autumn they come up the succeeding spring, but if sown in spring they often remain a year in the ground. Loudon says that seeds from the highest branches of old trees are most likely to germinate. It is readily propagated from cuttings and easily transplanted.[1]

In landscaping

Mature example of the east central Florida ecotype Dr. Howard A. Kelly Park near Apopka, Florida.
Flower of east central Florida ecotype near Lake Worth, Florida. Flower is smaller and yellower than in most northern upland types.

Tulip trees make magnificently-shaped specimen trees, but are very large, growing to about 35 m in good soil. They grow best in deep well-drained loam which has thick dark topsoil. They show stronger response to fertilizer compounds (those with low salt index are preferred) than most other trees, but soil structure and organic matter content are more important. The southeastern coastal plain and east central Florida ecotypes occur in wet but not stagnant soils which are high in organic matter. All tulip trees are unreliable in clay flats which are subject to ponding and flooding. Like other members of the Magnolia family, they have fleshy roots that are easily broken if handled roughly. Transplanting should be done in early spring, before leaf-out; this timing is especially important in the more northern areas. Fall planting is often successful in Florida. The east central Florida ecotype may be more easily moved than other strains because its roots grow over nine or ten months every year—several months longer than other ecotypes. Most tulip trees have low tolerance of drought, although Florida natives (especially the east central ecotype) fare better than southeastern coastal plain or northern inland specimens.

It is recommended as a shade tree.[1]

L. tulipifera has been introduced to many temperate parts of the world, at least as far north as Sykkylven, Norway. In the Southern Hemisphere, it is cultivated in parts of Argentina, Australia (at least as far north as Sydney), Chile, New Zealand, South Africa, and Uruguay. In Canada, it is native to that part of Ontario south of a line from Hamilton to Sarnia, with many specimens in Rondeau Provincial Park, but most cultivation is seen in British Columbia. There, it grows in Prince Rupert, and in the southern interior as far north as Vernon. Its easternmost cultivation is at Creston. It is common in southwestern cities such as Burnaby, New Westminster, Port Alberni, Vancouver and Victoria. In the United States, introductions have been most successful in parts of Washington, Oregon, California, Oklahoma and Texas. A few are in Idaho, Nevada, Utah, Colorado, Nebraska, Kansas, South Dakota, Iowa, Minnesota, Wisconsin, New Hampshire and Maine. The east central Florida ecotype grows well in Palm Beach County, Florida and Austin, Texas.

Honey

This tree species is a major honey plant in the eastern United States, yielding a dark reddish, fairly strong honey which gets mixed reviews as a table honey but is favorably regarded by bakers. Nectar is produced in the orange parts of the flowers. Some specimens may be poor nectar producers simply because they have relatively little orange in their flowers. On the other hand, the east central Florida ecotype may secrete copious amounts of nectar (see the images of its flowers below).

Wood

The soft, fine-grained wood of tulip trees is misleadingly known as "poplar" (short for "yellow poplar") in the U.S., but marketed abroad as "American tulipwood" or by other names. It is very widely used where a cheap, easy-to-work and stable wood is needed. The sapwood is usually a creamy off-white color. While the heartwood is usually a pale green, it can take on streaks of red, purple, or even black; depending on the extractives content (i.e. the soil conditions where the tree was grown, etc). It is clearly the wood of choice for use in organs, due to its ability to take a fine, smooth, precisely-cut finish and so to effectively seal against pipes and valves. It is also commonly used for siding clapboards. Its wood may be compared in texture, strength, and softness to white pine.

Used for interior finish of houses, for siding, for panels of carriages, for coffin boxes, pattern timber, and wooden ware. During scarcity of the better qualities of white pine, tulip wood has taken its place to some extent, particularly when very wide boards are required.[1]

Cultivars

History

In the Cretaceous age the genus was represented by several species, and was widely distributed over North America and Europe. Its remains are also found in Tertiary rocks.[1]

See also

References and external links

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Keeler, Harriet L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons. pp. 14–19. 
  2. ↑ [1] Richard T. Busing, "Disturbance and the Population Dynamics of Liriodendron Tulipifera: Simulations with a Spatial Model of Forest Succession", Journal of Ecology, Vol. 83, No. 1. (Feb., 1995), pp. 45-53.
  3. ↑ Parks CR, Wendel JF, Sewell MM, Qiu Y-L (1994). The significance of allozyme variation and introgression in the Liriodendron tulipifera complex (Magnoliaceae). Amer. J. Bot. 81 (7): 878-889 abstract and first page
  4. ↑ 4.0 4.1 [2] Silvics of North America, USDA Forest Service (1990)