Tree cotton can be grown in the dry to moist tropics and subtropics, where it is found at elevations up to 1,600 metres. For commercial production it requires a climate that has a long, hot growing season with abundant moisture, followed by a drier period for harvesting the seed floss[200 ]. It grows best in areas where annual daytime temperatures are within the range 26 - 36°c, but can tolerate 18 - 38°c[418 ]. It prefers a mean annual rainfall in the range 750 - 1,250mm, but tolerates 500 - 1,500mm[418 ]. Prefers a very sunny position in a light, fertile, well-drained soil[200 ]. Plants can tolerate a range of soils, including moderate levels of salt[418 ]. Prefers a pH in the range 6 - 7.2, tolerating 5.3 - 8.5[418 ]. Requires a position sheltered from strong winds[418 ]. There are two main forms of the plant:- var. Neglecta produces very short fibres[46 ]. Var. Sanguinea produces strong, good quality fibre[46 ]. Carbon Farming - Cultivation: regional crop. Management: standard, coppice. Perennial cotton has longer fibres and is considered superior to annual cottons. Perennial cottons are suited to arid and humid conditions while annual cottons were bred for colder climates and for mechanical harvesting. Perennial cottons are cultivated in the tropics on a smaller scale and include Gossypium arboreum burmanicum, Gossypium arboreum indicum, Gossypium arboreum soudanense, Gossypium barbadense braziliense, Gossypium barbadense darwinii, Gossypium herbaceum acerifolium, Gossypium herbaceum africanum, Gossypium hirsutum marie-galante, Gossypium hirsutum punctatum, Gossypium hirsutum taitense. Currently perennial cottons are harvested by hand. Researching perennial cottons varieties and production methods would help develop them as good carbon farming plants and help to alleviate the terrible problems caused by annual cottons.