TAXODIUM DISTICHUM

'''Taxodium distichum''', also known as 'baldcypress', 'bald cypress', or 'swamp cypress', is a species of deciduous conifer native to the southeastern United States. The closely related pondcypress (''Taxodium ascendens'') was once classified as ''Taxodium disticum'' var. ''nutans''.

Contents

Habitat

Range

Weather

Soils and Topography

Life History

Reproduction

Early Growth

Mature Trees

Death

Cypress Wood

References and external links

Habitat

Range

The native range of ''Taxodium distichum'' extends from Delaware Bay south to Florida and west to southern Texas and Southeastern Oklahoma-(Little Dixie region, Oklahoma), and also inland up the Mississippi and Ohio Rivers north to southern Illinois, Indiana. The baldcypress range has been significantly extended due to many trees having been successfully introduced into many of the southern Ohio River counties of Ohio. [1]
Ancient Baldcypress forests, with some trees more than 1200 years old, once dominated swamps in the southeast US. The largest remaining old-growth stand of Baldcypress is at Corkscrew Swamp Sanctuary, near Naples, Florida. These trees are around 500 years of age and some exceed 40m (130 ft) in height. The largest individual specimen is "The Senator", near Longwood, Florida; it is 35 m tall, and with a trunk diameter of 344 cm.

Weather

''Taxodium distichum'' is native to humid climates where precipitation ranges from about 760 mm (in Texas) to 1630 mm (along the Gulf Coast).
Although it grows best in warm climates, the natural northern limit of the species is not due to a lack of cold tolerance, but to specific reproductive requirements: further north, regeneration is prevented by ice damage to seedlings. Larger trees are able to tolerate much lower temperatures and lower humidities, and can be grown at least as far outside of the natural range as Minnesota and Colorado. It is commonly planted elsewhere outside of its native range in other temperate regions of the world.

Soils and Topography

Most baldcypress grow on flat topography, usually at elevations of less than 50m above sea level, although some stands may occur at elevations of 500m in Texas.
Baldcypress occurs mainly along riparian (riverside) wetlands normally subject to periodic flooding by silt-rich 'brownwater' rivers, unlike the related ''Taxodium ascendens'', which occurs in silt-poor blackwater rivers and ponds. Baldcypress tolerates minor salinity, but does not grow in brackish or saline coastal waters.

Life History

Reproduction

Baldcypress is monoecious. Male and female strobili mature in one growing season from buds formed the previous year. The cones are green maturing gray-brown, globular, 2-3.5 cm in diameter. They hold from 9 to 15 4-sided scales, each bearing up to two triangle-shaped seeds. Thus, number of seeds per cone ranges from 2 to 34. Seeds remain viable for less than one year.
The seeds are 5-10 mm long, the largest of any species in the cypress family, and are produced every year. Cones disintegrate when mature to release the large seeds which then disperse in two ways. One is by water: the cone floats and moves on water until flooding recedes or the cone is deposited on shore. The second is by wildlife: squirrels eat seeds but usually leave some scales fall of the cone they pick.
Although vigorous saplings and stump sprouts can produce viable seed, most baldcypress do not reliably produce seed until they are about 30 years old or 8 inches in diameter.

Early Growth

Seeds do not germinate under water and rarely germinate on well drained soils; seedlings normally become established on soil that is continuously saturated, but not flooded, for 1 to 3 months.
After germination, seedlings must grow quickly to escape floodwaters: they often reach a height of 8 to 30 inches in their first year. Seedlings die if inundated for more than about 2-4 weeks. Natural regeneration is therefore prevented on sites that are flooded during the growing season.

Mature Trees

Baldcypress is a large tree, reaching 30-45 m tall and trunk diameter of up to 3 m. The leaves are borne on deciduous branchlets that are are spirally arranged on the stem but twisted at the base to lie in two horizontal ranks, 1-2 cm long and 1-2 mm broad; unlike most other species in the family Cupressaceae, it loses the leaves in the winter months, hence the name 'Bald.'

Baldcypress grow very slowly, and some individuals can live over 1,000 years. It may difficult to determine the age of an old tree because of frequent missing or false rings of stemwood caused by variable and stressful growing environments.
Baldcypress growing in swamps have a peculiarity of growth called cypress knees. These are woody projections sent above the ground or water that are part of the root system. Their function was once thought to be to provide oxygen to the roots, which grow in the low dissolved oxygen (DO) waters typical of a swamp (as in mangroves). However, there is little evidence for this; 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 that of structural support and stabilization. Baldcypress growing on flood-prone sites tend to form buttressed bases, but trees grown on drier sites may lack this feature. Buttressed bases and a strong, intertwined root system allows them to resist very strong winds: even hurricanes rarely overturn them.

Death

Many agents damage cypress trees : insects like the cypress flea beetle or the baldcypress leafroller (''Archips goyerana'') (closely related to the fruit tree leafroller) can seriously damage cypress trees by destroying leaves, cones or the bark of tree. A few fungi attack the sapwood and the heartwood of the tree, but they don't usually cause serious damage. However, there are two main lethal damaging agents for a cypress:

★ The fungus ''Stereum taxodi'' causes a brown pocket rot known as "pecky cypress". It attacks the heartwood of living trees, usually from the crown down to the roots.

★ Nutria clip and unroot young cypress seedlings, sometimes killing a whole plantation in a short amount of time.

Cypress Wood

Baldcypress has been noted for its high merchantable yields. In virgin stands, yields from 112 to 196 m3/ha were common, and some stands might have exceeded 1000 m3/ha. Cypress swamps are some of the world's most productive ecosystems.
Baldcypress wood has long been valued for its water resistance. Still-usable prehistoric wood is often found in swamps in New Jersey and occasionally as far north as New England although it is more common in the southeast. The somewhat-mineralized wood is mined from some swamps in the southeast, and is highly prized for specialty uses such as wood carvings. Pecky cypress, caused by the fungus ''Strereum taxodii'' is used where durability of wood is an important factor, and as decorative wall paneling.
The Baldcypress was designated the official state tree of Louisiana in 1963, and is considered by some to be a symbol of the southern swamps.

References and external links

★

★ ''Taxodium distichum'' Images at bioimages.vanderbilt.edu

★ Detailed article on ''Taxodium distichum''

★ Native Plant Information Network More information on ''Taxodium distichum''