Taxodium distichum
Taxodium distichum 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
Taxodium distichum is a large, slow-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 bald cypress is deciduous.
This species is monoecious, with male and female cones on a single plant forming on slender, tassel-like structures near the edge of branchlets. The tree produces cones in April and the seeds ripen in October. The male and female strobili are produced from buds formed in late autumn, with pollination in early winter, and mature in about 12 months. Male cones emerge on panicles that are inches long. Female cones are round, resinous and green while young. They then turn hard and then brown as the tree matures. They are globular and in diameter. They have from 20 to 30 spirally arranged, four-sided scales, each bearing one, two, or rarely three triangular seeds. Each cone contains 20 to 40 large seeds. The cones disintegrate at maturity to release the seeds. The seeds are long, the largest of any species of Cupressaceae, and are produced every year, with heavy crops every 3–5 years. The seedlings have three to nine, but usually six, cotyledons each.
The bald cypress grows in full sunlight to partial shade; it grows best in wet or well-drained soil, but can tolerate dry soil. It is moderately able to grow in aerosols of salt water. It does well in acid, neutral, and alkaline soils across the full range of light, medium, and heavy soils. It can also grow in saline soils. It can tolerate atmospheric pollution. The cones are often consumed by wildlife.
The tallest known specimen, near Williamsburg, Virginia, is 44.11 m tall, and the stoutest known, in the Real County near Leakey, Texas, has a circumference of 475 in. The National Champion Bald Cypress is recognized as the largest member of its species in the country and is listed as such on the National Register of Champion Trees by American Forest. The National Champion Bald Cypress is in the Cat Island National Wildlife Refuge, near St. Francisville, Louisiana, and it is tall, in circumference, and is estimated to be approximately 1,500 years old. The oldest known living specimen, found along the Black River in North Carolina, is at least 2,624 years old, rendering it the oldest living tree in eastern North America.
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 is treated by some botanists as a distinct species, while others classify it as merely a variety of bald cypress, as Taxodium distichum var. imbricatum Croom. It differs in shorter leaves borne on erect shoots, and in ecology, being largely confined to low-nutrient blackwater habitats. A few authors also treat Taxodium mucronatum as a variety of bald cypress, as T. distichum var. mexicanum Gordon, thereby considering the genus as comprising only one species.Habitat and distribution
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. 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.The largest remaining old-growth stands are at Corkscrew Swamp Sanctuary, near Naples, Florida, and in the Three Sisters tract along eastern North Carolina's Black River. The Corkscrew trees are around 500 years of age, and some exceed in height. In 1985, the Black River trees were cored by a dendrochronologist from the University of Arkansas, who found that some began growing as early as 364 AD. A subsequent visit to the area in 2019 revealed a tree dated by its tree-ring count to 605 BC, ranking as the ninth-oldest tree in the world.
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
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 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.Seed production and dissemination
Some seeds are produced every year, and good seed crops occur at three- to five-year intervals. At maturity, the cone scales with their resin-coated seeds adhering to them, or sometimes entire cones, drop to the water or ground. 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.Seedling development
is epigeal. Under swamp conditions, germination generally takes place on a sphagnum moss or a wet-muck seedbed. Seeds will not germinate under water, but some will remain viable for 30 months under water. By contrast, seeds usually fail to germinate on better drained soils because of the lack of surface water. Thus, a soil saturated but not flooded for a period of one to three months after seedfall is required for germination.After germination, seedlings must grow fast enough to keep at least part of their crowns above floodwaters for most of the growing season. 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.
In nurseries, Taxodium distichum seeds show an apparent internal dormancy that can be overcome by various treatments, usually including cold stratification or submerging in water for 60 days. Nursery beds are sown in spring with pretreated seeds or in fall with untreated seeds. Seedlings usually reach in height during their first year in the nursery. Average size of 1-0 nursery-grown seedlings in a seed source test including 72 families was tall and in diameter.
Control of competing vegetation may be necessary for a year or more for bald cypress planted outside of swamps. Five years after planting on a harrowed and bedded, poorly drained site in Florida, survival was high, but heights had increased only, probably because of heavy herbaceous competition. Seedlings grown in a crawfish pond in Louisiana, where weed control and soil moisture were excellent through June, averaged and diameter at breast height after five years. However, a replicate of the same sources planted in an old soybean field, where weed control and soil moisture were poor, resulted in the same diameter, but a smaller average seedling height of. When planted in a residential yard and weeded and watered, they averaged tall three years later.