Bamboo


The bamboos En-us-bamboo.ogg listen  are a group of woody perennial evergreen (except for certain temperate species) plants in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Some are giant bamboos, the largest members of the grass family. Bamboos are the fastest growing woody plants in the world. Their growth rate (up to 60 centimeters (24 in.)/day) is due to a unique rhizome-dependent system, but is highly dependent on local soil and climate conditions. They are of economic and high cultural significance in East Asia and South East Asia where they are used extensively in gardens, as a building material, and as a food source.
There are more than 70 genera divided into about 1,000 species.[1] They are found in diverse climates, from cold mountains to hot tropical regions. They occur across East Asia, from 50°N latitude in Sakhalin[citation needed] through to Northern Australia, and west to India and the Himalayas.[2] They also occur in sub-Saharan Africa, and in the Americas from the Mid-Atlantic United States[3] south to Argentina and Chile, reaching their southernmost point anywhere, at 47°S latitude. Major areas with no native bamboos include Europe and Antarctica.[4]

Bamboo is the fastest-growing plant on Earth; it has been measured surging skyward as fast as 121 cm (48 in) in a 24-hour period,[5] and can also reach maximal growth rate exceeding one meter (39 inches) per hour for short periods of time. Many prehistoric bamboos exceeded heights of 75 metres (250 ft). Primarily growing in regions of warmer climates during the Cretaceous period, vast fields existed in what is now Asia.
Growth
Unlike trees, all bamboos grow to full height and girth in a single growing season of 3–4 months. During this first season, the clump of young shoots grow vertically, with no branching. In the next year, the pulpy wall of each culm slowly dries and hardens. The culm begins to sprout branches and leaves from each node. During the third year, the culm further hardens. The shoot is now considered a fully mature culm. Over the next 2–5 years (depending on species), fungus and mould begin to form on the outside of the culm, which eventually penetrate and overcome the culm. Around 5 – 8 years later (species and climate dependent), the fungal and mold growth cause the culm to collapse and decay. This brief life means culms are ready for harvest and suitable for use in construction within 3 – 7 years.



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