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Tamarix

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Tamarisk redirects here. For other uses of tamarisk, see Tamarisk (disambiguation)

The genus Tamarix (tamarisk) comprises about 50-60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa.

They are deciduous or evergreen shrubs or small trees growing to 1-15 m in height and forming dense thickets, The largest, Tamarix aphylla, is an evergreen tree that can grow to 15 m tall. They usually grow on saline soils, tolerating up to 15,000 ppm soluble salt and can also tolerate alkali conditions. Tamarisks are characterized by slender branches and grey-green foliage. The bark of young branches is smooth and reddish-brown. As the plants age, the bark becomes brownish-purple, ridged and furrowed. The leaves are scale-like, 1-2 mm long, and overlap each other along the stem. They are often encrusted with salt secretions. The pink to white flowers appear in dense masses on 5-10 cm long spikes at branch tips from March to September, though some species (e.g. T. aphylla) tend to flower during the winter.

Tamarix can spread both vegetatively, by adventitious roots or submerged stems, and sexually, by seeds. Each flower can produce thousands of tiny (1 mm diameter) seeds that are contained in a small capsule usually adorned with a tuft of hair that aids in wind dispersal. Seeds can also be dispersed by water. Seedlings require extended periods of soil saturation for establishment. Tamarix species are fire-adapted, and have long tap roots that allow them to intercept deep water tables and exploit natural water resources. They are able to limit competition from other plants by taking up salt from deep ground water, accumulating it in their foliage, and from there depositing it in the surface soil where it builds up concentrations temporarily detrimental to some plants. The salt is washed away during heavy rains.

Tamarix species are used as food plants by the larvae of some Lepidoptera species including Coleophora asthenella which feeds exclusively on T. africana.Selected species

  • Tamarix gallica
  • Tamarix gansuensis
  • Tamarix gracilis
  • Tamarix hampeana
  • Tamarix hispida
  • Tamarix hohenackeri
  • Tamarix indica
  • Tamarix jintaenia
  • Tamarix juniperina
  • Tamarix karelinii
  • Tamarix laxa
    		•
  • Tamarix leptostachys
  • Tamarix meyeri
  • Tamarix mongolica
  • Tamarix parviflora
  • Tamarix ramosissima
  • Tamarix sachuensis
  • Tamarix smyrnensis
  • Tamarix taklamakanensis
  • Tamarix tarimensis
  • Tamarix tenuissima
  • Tamarix tetrandra

    • North American invasive species

    Tamarix was introduced to the western United States (where it is often called "saltcedar") as an ornamental shrub in the early 1800s. It establishes in disturbed and undisturbed streams, waterways, bottomlands, banks and drainage washes of natural or artificial waterbodies, moist rangelands and pastures, and other areas where seedlings can be exposed to extended periods of saturated soil for establishment.

    It is commonly believed that Tamarix disrupts the structure and stability of North American native plant communities and degrades native wildlife habitat by outcompeting and replacing native plant species, salinizing soils, monopolizing limited sources of moisture, and increasing the frequency, intensity and effect of fires and floods. While it has been shown that individual plants may not consume larger quantities of water than native species (Anderson, 1996,1998) it has also been shown that large dense stands of Tamarix do consume more water than equivalent stands of native Cottonwoods (Sala 1996). There is an active and ongoing debate as to when Tamarix can outcomplete native plants and if it is actively displacing native plants or it just taking advantage of disturbance by removal of natives by humans and changes in flood regimes . Research on competition between Tamarix seedlings and co-occurring native trees has found that the seedlings are not competitive over a range of environments , however stands of mature trees effectively prevent native species establishment in the understory, due to low light, elevated salinity, and possibly changes to the soil biota (e.g. and . Thus, anthropogenic activities that preferentially favor tamarisk (such as changes to flooding regimes) are associated with infestation . To date, Tamarix has taken over large sections of riparian ecosystems in the Western United States that were once home to native cottonwoods and willows , and are projected by some to spread well beyond the current range .

    Miscellaneous

    In Genesis 21:33, Abraham is recorded to have "planted a tamarisk at Beer-sheba". He had built a well there earlier.

    In a campaign in the computer game, Age of Mythology, the head of Osiris is said to be hidden inside a great Tamarisk tree.

    References