Taxodium distichum (baldcypress, bald-cypress, bald cypress, swamp cypress; ;
cipre in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the Southeastern United States. Hardy and tough, this tree adapts to a wide range of soil types, whether wet, salty, dry, or swampy. It is noted for the russet-red fall color of its lacy needles.
This plant has some cultivated varieties and is often used in groupings in public spaces. Common names include bald cypress, swamp cypress, white cypress, tidewater red cypress, gulf cypress, and red cypress.
The bald cypress was designated the official state tree of Louisiana in 1963.
Bald cypress trees are valued because of their rot-resistant heartwood when the trees are mature. Because of this, the trees are often used for making fence posts, doors, flooring, caskets, and a number of other items.
Description
thumb|left|Cypress grove in winter
Taxodium distichum is a large, slow to fast-growing, and long-lived tree. It typically grows to heights of and has a trunk diameter of .
The main trunk is often surrounded by cypress knees. The bark is grayish brown to reddish brown, thin, and fibrous with a stringy texture; it has a vertically interwoven pattern of shallow ridges and narrow furrows.
The needle-like leaves are long and are simple, alternate, green, and linear, with entire margins. In autumn, the leaves turn yellow or copper red.
The tallest known specimen, near Williamsburg, Virginia, is 44.11 m (145 ft) tall.
The Senator, a bald cypress in Longwood, Florida, was tall before the hurricane of 1925, when it lost about in height. It had a circumference of and a diameter of and was estimated to be 3,500 years old. It was burned down accidentally in 2012.
Taxonomy
The closely related Taxodium ascendens (pond cypress) is treated by some botanists as a distinct species, while others classify it as merely a variety of bald cypress,
Habitat and distribution
thumb|Bald cypress in [[Trap Pond State Park, Delaware]]
thumb|right|Bald cypress on the [[Texas side of Caddo Lake]]
The native range extends from southeastern New Jersey south to Florida and west to Central Texas and southeastern Oklahoma, and also inland up the Mississippi River to southernmost Illinois and Indiana. Ancient bald cypress forests, with some trees more than 1,700 years old, once dominated swamps in the Southeast. The original range had been thought to only reach as far north as Delaware, but researchers have now found a natural forest on the Cape May Peninsula in southern New Jersey. The species can also be found growing outside its natural native range, in New York and Pennsylvania.
thumb|Bald cypress (Taxodium distichum) growing near the western extreme of its range on the Guadalupe River in the semi-arid [[Edwards Plateau, Kerr County, Texas (14 April 2012)]]In 2012, scuba divers discovered an underwater cypress forest several miles off the coast of Mobile, Alabama, in 60 feet of water. The forest contains trees that could not be dated with radiocarbon methods, indicating that they are more than 50,000 years old and thus most likely lived in the early glacial interval of the last ice age. The cypress forest is well preserved, and when samples are cut, they still smell like fresh cypress. A team, which has not yet published its results in a peer-reviewed journal, is studying the site. One possibility is that Hurricane Katrina exposed the grove of bald cypress, which had been protected under ocean floor sediments.
Reproduction and early growth
thumb|right|Foliage in autumn just before shedding
The bald cypress is monoecious. Male and female strobili mature in one growing season from buds formed the previous year. The male catkins are about in diameter and are borne in slender, purplish, drooping clusters long that are conspicuous during the winter on this deciduous conifer. Pollen is shed in March and April. Female conelets are found singly or in clusters of two or three. The globose cones turn from green to brownish-purple as they mature from October to December. The cones are in diameter and consist of 9 to 15 four-sided scales that break away irregularly after maturity. Each scale can bear two (rarely three) irregular, triangular seeds with thick, horny, warty coats and projecting flanges. The number of seeds per cone averages 16 and ranges from 2 to 34. Cleaned seeds number from about 5,600 to 18,430 per kg (2,540 to 8,360 per lb). This drop of mature seeds is often hastened by squirrels, which eat bald cypress seeds, but usually drop several scales with undamaged seeds still attached to each cone they pick. Floodwaters spread the scales or cones along streams and are the most important means of seed dissemination. Bald cypress seedlings can endure partial shading, but require overhead light for good growth. Seedlings in swamps often reach heights of their first year. Growth is checked when a seedling is completely submerged by flooding, and prolonged submergence kills the seedling. Successful vegetative propagation has been recorded when cuttings were not wounded, treated with 15,000 mg/L of Indole-3-butyric acid, and grown in a substrate with intermediate water-holding capacity.
Ecology
left|thumb|125px|A bald cypress in the Atchafalaya Basin of Louisiana
thumb|left|125px|Bald cypress knees in [[duckweed]]
The seeds remain viable for less than one year, and are dispersed in two ways. One is by water: the seeds float and move on water until flooding recedes or the cone is deposited on shore. The second is by wildlife: squirrels eat seeds, but often drop some scales from the cones they harvest. Seeds do not germinate under water and rarely germinate on well-drained soils; seedlings normally become established on continuously saturated, but not flooded, soils for one to three months. After germination, seedlings must grow quickly to escape floodwaters; they often reach a height of 20–75 cm (up to 100 cm in fertilized nursery conditions) in their first year. Seedlings die if inundated for more than about two to four weeks. Natural regeneration is therefore prevented on sites that are always flooded during the growing season. Although vigorous saplings and stump sprouts can produce viable seed, most specimens do not produce seed until they are about 30 years old. In good conditions, bald cypress grows fairly fast when young, then more slowly with age. Trees have been measured to reach in five years, in 41 years, and in height in 96 years; height growth has largely ceased by the time the trees are 200 years old. Some individuals can live over 1,000 years. Determination of the age of an old tree may be difficult because of frequent missing or false rings of stemwood caused by variable and stressful growing environments.
thumb|Bald cypress forest in winter, showing "knees" and (brown) high flood level, Lynches River, [[Johnsonville, South Carolina]]
Bald cypress trees growing in swamps have a peculiarity of growth called cypress knees. These are woody projections from the root system project above the ground or water. Their function was once thought to be to provide oxygen to the roots, which grow in the low dissolved oxygen waters typical of a swamp (as in mangroves). However, evidence for this is scant; in fact, roots of swamp-dwelling specimens whose knees are removed do not decrease in oxygen content and the trees continue to thrive. Another more likely function is structural support and stabilization. Bald cypress trees growing on flood-prone sites tend to form buttressed bases, but trees grown on drier sites may lack this feature. The buttressed base usually begins at the soil surface and usually extends up to the maximum annual flooding elevation. Buttressed bases and a strong, intertwined root system allow them to resist very strong winds; even hurricanes rarely overturn them., which causes a brown pocket rot known as "pecky cypress". It attacks the heartwood of living trees, usually from the crown down to the roots. A few other fungi attack the sapwood and the heartwood of the tree, but they do not usually cause serious damage. Insects such as the cypress flea beetle (Systena marginalis) and the bald cypress leafroller (Archips goyerana) can seriously damage trees by destroying leaves, cones, or bark. Nutrias also clip and unroot young bald cypress seedlings, sometimes killing a whole plantation in a short amount of time. and do not produce cones. One of the oldest specimens in Europe was planted in the 1900s in the Arboretum de Pézanin in Burgundy, France. An alley of Louisiana cypress trees was planted in the 18th century in the park of the Château de Rambouillet, southwest of Paris.
Bald cypress has great merchantable yields. In virgin stands, yields from 112 to 196 m<sup>3</sup>/ha were common, and some stands may have exceeded 1,000 m<sup>3</sup>/ha.
Building material
Still usable prehistoric wood is often found in swamps as far north as New Jersey, and occasionally as far north as Connecticut, although it is more common in the southeastern states. This partially mineralized wood is harvested from swamps in the southeastern states, and is greatly prized for special uses such as for carvings. The fungus Lauriliella taxodii
In the southern United States, the odorless wood, which closely resembles that of other Cupressus species, has been valued since colonial times for its resistance to water, making it ideal for use wherever the wood is exposed to the elements. In the first half of the 20th century, it was marketed as "The Wood Eternal".
The lumber is valuable for timber framing, building materials, fence posts, planking in boats, river pilings, doors, blinds, flooring, shingles, garden boxes, caskets, interior trim, and cabinetry.
Bald cypress timbers are commonly available in lengths up to 24 feet. This species enjoys predictable lead times for projects. The wood is a very light tan in color and weathers to a uniform silvery gray. Paint and stains adhere well to Bald cypress. Bald cypress most often sees use in outdoor structures such as timber frame pavilions, mid-size farmers' markets, porches, exterior awnings, and decorative trusses where its weather resistance helps ensure long life.