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Maggie Schnair
In bamboo, as in other grasses, the internodal regions of the stem are usually hollow and the vascular bundles in the cross-section are scattered throughout the walls of the culm instead of in a cylindrical cambium layer between the bark (phloem) and the wood (xylem) as in dicots and conifers. The dicotyledonous woody xylem is also absent. The absence of secondary growth wood causes the stems of monocots, including the palms and large bamboos, to be columnar rather than tapering.[12]
Bamboo is versatile and has notable economic and cultural significance in South Asia, Southeast Asia, and East Asia, being used for building materials, as a food source, and as a raw product, and depicted often in arts, such as in bamboo paintings and bambooworking. Bamboo, like wood, is a natural composite material with a high strength-to-weight ratio useful for structures.[19] Bamboo's strength-to-weight ratio is similar to timber, and its strength is generally similar to a strong softwood or hardwood timber.[20][21] Some bamboo species have displayed remarkable strength under test conditions. Bambusa tulda of Bangladesh and adjoining India has tested as high as 60,000 psi (400 MPa) in tensile strength.[22] Other bamboo species make extraordinarily hard material. Bambusa tabacaria of China contains so much silica that it will make sparks when struck by an axe.[23]
The bamboos comprise three clades classified as tribes, and these strongly correspond with geographic divisions representing the New World herbaceous species (Olyreae), tropical woody bamboos (Bambuseae), and temperate woody bamboos (Arundinarieae).[26][5] The woody bamboos do not form a monophyletic group; instead, the tropical woody and herbaceous bamboos are sister to the temperate woody bamboos.[1][24] Altogether, more than 1,400 species are placed in 115 genera.[1]
In the Asia-Pacific region they occur across East Asia, from north to 50 N latitude in Sakhalin,[28] to south to northern Australia, and west to India and the Himalayas. China, Japan, Korea, India and Australia, all have several endemic populations.[29] They also occur in small numbers in sub-Saharan Africa, confined to tropical areas, from southern Senegal in the north to southern Mozambique and Madagascar in the south.[30] In the Americas, bamboo has a native range from 47 S in southern Argentina and the beech forests of central Chile, through the South American tropical rainforests, to the Andes in Ecuador near 4,300 m (14,000 ft), with a noticeable gap through the Atacama Desert.
Three species of bamboo, all in the genus Arundinaria, are also native through Central America and Mexico, northward into the Southeastern United States.[31] Bamboo thickets called canebrakes once formed a dominant ecosystem in some parts of the Southeastern United States, but they are now considered critically endangered ecosystems.[32][33][34] Canada and continental Europe are not known to have any native species of bamboo.[35] Many species are also cultivated as garden plants outside of this range, including in Europe and areas of North America where no native wild bamboo exists.
Recently, some attempts have been made to grow bamboo on a commercial basis in the Great Lakes region of east-central Africa, especially in Rwanda.[36] In the United States, several companies are growing, harvesting, and distributing species such as Phyllostachys nigra (Henon) and Phyllostachys edulis (Moso).[37]
The two general patterns for the growth of bamboo are "clumping", and "running", with short and long underground rhizomes, respectively. Clumping bamboo species tend to spread slowly, as the growth pattern of the rhizomes is to simply expand the root mass gradually, similar to ornamental grasses. Running bamboos need to be controlled during cultivation because of their potential for aggressive behavior. They spread mainly through their rhizomes, which can spread widely underground and send up new culms to break through the surface. Running bamboo species are highly variable in their tendency to spread; this is related to the species, soil and climate conditions. Some send out runners of several meters a year, while others stay in the same general area for long periods. If neglected, over time, they can cause problems by moving into adjacent areas.
Bamboos seldom and unpredictably flower and the frequency of flowering varies greatly from species to species. Once flowering takes place, a plant declines and often dies entirely. In fact, many species only flower at intervals as long as 65 or 120 years. These taxa exhibit mass flowering (or gregarious flowering), with all plants in a particular 'cohort' flowering over a several-year period. Any plant derived through clonal propagation from this cohort will also flower regardless of whether it has been planted in a different location. The longest mass flowering interval known is 120 years, and it is for the species Phyllostachys bambusoides (Sieb. & Zucc.).[38] In this species, all plants of the same stock flower at the same time, regardless of differences in geographic locations or climatic conditions, and then the bamboo dies.[39] The commercially important bamboo Guadua, or Cana brava (Guadua angustifolia) bloomed for the first time in recorded history in 1971, suggesting a blooming interval well in excess of 130 years.[citation needed] The lack of environmental impact on the time of flowering indicates the presence of some sort of "alarm clock" in each cell of the plant which signals the diversion of all energy to flower production and the cessation of vegetative growth.[40] This mechanism, as well as the evolutionary cause behind it, is still largely a mystery.
Some bamboo species are acknowledged as having high potential for becoming invasive species. A study commissioned by International Bamboo and Rattan Organisation, found that invasive species typically are varieties that spread via rhizomes rather than by clumping, as most commercially viable woody bamboos do.[41] In the United States, the National Invasive Species Information Center agency of the Department of Agriculture has Golden Bamboo (Phyllostachys aurea) listed as an invasive species.[42]
Bamboo contains large amounts of protein and very low amounts of carbohydrates allowing this plant to be the source of food for many animals.[44] Soft bamboo shoots, stems and leaves are the major food source of the giant panda[45] of China, the red panda[46] of Nepal, and the bamboo lemurs of Madagascar.[47] The red panda can eat up to 9 pounds (4.1 kg) a day which is also about the full body weight of the animal.[47] With raw bamboo containing trace amounts of harmful cyanide with higher concentrations in bamboo shoots, the golden bamboo lemur ingests many times the quantity of the taxiphyllin-containing bamboo that would be lethal to a human.[47]
Mountain gorillas of Central Africa also feed on bamboo, and have been documented consuming bamboo sap which was fermented and alcoholic;[30] chimpanzees and elephants of the region also eat the stalks. The larvae of the bamboo borer (the moth Omphisa fuscidentalis) of Laos, Myanmar, Thailand and Yunnan, China feed off the pulp of live bamboo. In turn, these caterpillars are considered a local delicacy. Bamboo is also used for livestock feed with research showing some bamboo varieties have higher protein content over other varieties of bamboo.[48]
Bamboo forestry (also known as bamboo farming, cultivation, agriculture or agroforestry) is a cultivation and raw material industry that provides the raw materials for the broader bamboo industry, worth over 72 billion dollars globally in 2019.[49]
Historically a dominant raw material in South and South East Asia, the global bamboo industry has significantly grown in recent decades in part because of the high sustainability of bamboo as compared to other biomass cultivation strategies, such as traditional timber forestry. For example, as of 2016, the U.S. Fiber corporation Resource Fiber is contracting farmers in the United States for bamboo cultivation.[50][49] Or in 2009, United Nations Industrial Development Organization published guidelines for cultivation of bamboo in semi-arid climates in Ethiopia and Kenya.[51]
Because bamboo can grow on otherwise marginal land, bamboo can be profitably cultivated in many degraded lands.[52][53] Moreover, because of the rapid growth, bamboo is an effective climate change mitigation and carbon sequestration crop, absorbing between 100 and 400 tonnes of carbon per hectare.[54][55] In 1997, an international intergovernmental organization was established to promote the development of bamboo cultivation, the International Bamboo and Rattan Organisation.[56]
Bamboo is harvested from both cultivated and wild stands, and some of the larger bamboos, particularly species in the genus Phyllostachys, are known as "timber bamboos". Bamboo is typically harvested as a source material for construction, food, crafts and other manufactured goods.[57]
In Brazil, the Brazilian Center for Innovation and Sustainability - CEBIS, a non-profit organization, promotes the development of Brazil's bamboo production chain. Last year[when?], it helped with the approval of law n21,162 in the state of Paraná, which encourages Bamboo Culture aiming at the dissemination of its agricultural cultivation and the valorization of bamboo as an instrument for promoting the sustainable socioeconomic development of the State through its multiple functionalities. Bamboo cultivation neutralizes carbon emissions. Bamboo cultivation is cheap and in addition to adding value to its production chain, it is a sustainable crop that brings environmental, economic and social benefits. Its production can be used from construction to food. Recently, it was qualified and classified for the National Commission for Sustainable Development Objectives - CNDOS of the Presidency of the Republic of the federal government of Brazil.
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