Bamboo

twining twisting around while climbing tribe a group of closely related genera

tribe a group of closely related genera colonize to inhabit a new area biomass the total dry weight of an organism or group of organisms

Bamboos are members of the grass family (Poaceae). Like other grasses, bamboos have jointed stems, small flowers enclosed in structures known as spikelets, a specially modified embryo within the seed, and a grainlike fruit. However, bamboos are the only major group of grasses adapted to the forest habitat, and they differ from other grasses in having highly scalloped photosynthetic cells in their leaves. Many bamboos have tall, somewhat arched stems, but others are shrubby, or slender and twining, and some resemble ferns. The largest bamboos reach 30 meters (100 feet) in height and 30 centimeters (12 inches) in diameter, while the smallest ones have delicate stems no more than 10 centimeters (4 inches) tall.

There are at least twelve hundred known species of bamboos worldwide, which occur from 46°N (Sakhalin Island, Russia) to 47°S (southern Chile), although most are tropical or warm temperate. Bamboos often grow at low elevations, but many species grow in mountain forests, and some range up to 4,300 meters (14,200 feet) elevation in equatorial highlands. Woody bamboos (tribe Bambuseae), with at least eleven hundred species, make up the bulk of bamboo diversity: these are the plants normally thought of as bamboos. The woodiness of their stems is derived entirely from primary growth, and although there are other woody grasses, the Bambuseae are the only major group of grasses characterized by woodiness. Approximately one hundred species of tropical, herbaceous, broad-leaved grasses (tribe Olyreae) are closely related to their woody cousins, and these are now also classified as bamboos. Bamboos are typically associated with Asia, but close to one-half of their diversity is native to Central and South America, and there is one species (giant cane, or switch cane) native to the southeastern United States.

Woody bamboos are ecologically important in the tropical and temperate forests where they grow. Rapid elongation of bamboo shoots, tall, hard stems, and profuse vegetative branching allow woody bamboos to compete with trees for light. Woody bamboos easily colonize forest edges and gaps by means of vegetative reproduction through their well-developed underground stems (rhizomes), whereas herbaceous bamboos are characteristic of the shady forest floor. The large biomass of bamboo stems and leaves provides an excellent habitat for a wide variety of animals, including beetles and other insects, birds, monkeys, frogs, rats, and pandas.

Woody bamboos are well known for their unusual flowering behavior, in which the members of a species grow for many years (up to eighty or more) in the vegetative condition, and then flower at the same time and die after fruiting. Other flowering behaviors are documented in bamboos, but many exhibit this periodic, gregarious type of flowering, and the effect on the forest is dramatic when it occurs. Large areas of bamboo plants die back, providing openings for recolonization by the forest while the bamboo seeds sprout and start the next generation. How bamboo plants count the passage of time, or what triggers the gregarious flowering, is unknown.

In Asia, where a bamboo culture has existed for several thousand years, bamboos are a symbol of flexible strength, and they are an integral part of daily life. Young, tender bamboo shoots are a tasty vegetable, whereas the mature stems are used in construction, scaffolding, fencing, and bas-

ketry or for paper pulp. Mature stems are also fashioned into utensils, water pipes, musical instruments, and a multitude of other items. Bamboo is an important theme in Asian artwork, and bamboos frequently are used as a material for artwork. Bamboos are also widely planted as ornamentals in many parts of the world. The utility of bamboo is exploited wherever it is cultivated or grows naturally, and there is increasing recognition of the potential of bamboo as a renewable resource, especially for reforestation and housing. see also Economic Importance of Plants; Grasses; Monocots.

Lynn G. Clark

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