Bamboo


Bamboos are a diverse group of mostly evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in the case of Dendrocalamus sinicus having individual stalks reaching a length of, up to in diameter and a weight of up to. The internodes of bamboos can also be of great length. Kinabaluchloa wrayi has internodes up to in length. and Arthrostylidium schomburgkii has internodes up to in length, exceeded in length only by papyrus. By contrast, the stalks of the tiny bamboo Raddiella vanessiae of the savannas of French Guiana measure only in length by about in width. The origin of the word "bamboo" is uncertain, but it most likely comes from the Dutch or Portuguese language, which originally borrowed it from Malay.
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 stalk instead of in a cylindrical cambium layer between the bark and the wood 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.
Bamboos include some of the fastest-growing plants in the world, due to a unique rhizome-dependent system. Certain species of bamboo can grow within a 24-hour period, at a rate of almost an hour. Growth up to in 24 hours has been observed in the instance of Japanese giant timber bamboo. This rapid growth and tolerance for marginal land make bamboo a good candidate for afforestation, carbon sequestration and climate change mitigation.
Bamboo is versatile and has 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. Bamboo's strength-to-weight ratio is similar to timber, and its strength is generally similar to a strong softwood or hardwood timber. 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 in tensile strength. 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.

Taxonomy

Bamboos have long been considered the most basal grass genera, mostly because of the presence of bracteate, indeterminate inflorescences, "pseudospikelets", and flowers with three lodicules, six stamens, and three stigmata. Following more recent molecular phylogenetic research, many tribes and genera of grasses formerly included in the Bambusoideae are now classified in other subfamilies, e.g. the Anomochlooideae, the Puelioideae, and the Ehrhartoideae. The subfamily in its current sense belongs to the BOP clade of grasses, where it is sister to the Pooideae.
The bamboos comprise three clades classified as tribes, and these strongly correspond with geographic divisions representing the New World herbaceous species, tropical woody bamboos, and temperate woody bamboos. The woody bamboos do not form a monophyletic group; instead, the tropical woody and herbaceous bamboos are sister to the temperate woody bamboos. Altogether, more than 1,400 species are placed in 115 genera.
The bamboo taxonomy is in agreement with molecular phylogeny based on chloroplast DNA, reflecting the maternal line of descent. The nuclear genome of bamboos show a more complex pattern of branching due to the presence of subgenomes from ancient hybridization events leading to allopolyploidy. The herbaceous bamboos are diploid, the temperate woody ones are tetraploid, the neotropical woody ones are tetraploid, and the paleotropical woody ones are hexaploid.
22 genera:
  • Subtribe Buergersiochloinae
  • : one genus: Buergersiochloa.
  • Subtribe Olyrineae
  • : 18 genera: Agnesia, Arberella, Brasilochloa, Cryptochloa, Diandrolyra, Ekmanochloa, Froesiochloa, Lithachne, Maclurolyra, Mniochloa, Olyra, Parodiolyra, Piresiella, Raddia, Raddiella, Rehia, Reitzia, Sucrea.
  • Subtribe Parianinae
  • : three genera: Eremitis, Pariana, Parianella.
73 genera:
  • Subtribe Arthrostylidiinae:
  • : 15 genera: Actinocladum, Alvimia, Arthrostylidium, Athroostachys, Atractantha, Aulonemia, Cambajuva, Colanthelia, Didymogonyx, Elytrostachys, Filgueirasia, Glaziophyton, Merostachys, Myriocladus, Rhipidocladum.
  • Subtribe Bambusinae:
  • : 17 genera: Bambusa, Bonia, Cochinchinochloa, Dendrocalamus, Fimbribambusa, Gigantochloa, Maclurochloa, Melocalamus, Neomicrocalamus, Oreobambos, Oxytenanthera, Phuphanochloa, Pseudoxytenanthera, Soejatmia, Thyrsostachys, Vietnamosasa, Yersinochloa.
  • Subtribe Chusqueinae:
  • : one genus: Chusquea.
  • Subtribe Dinochloinae:
  • : 7 genera: Cyrtochloa, Dinochloa, Mullerochloa, Neololeba, Pinga, Parabambusa, Sphaerobambos.
  • Subtribe Greslaniinae:
  • : one genus: Greslania.
  • Subtribe Guaduinae:
  • : 5 genera: Apoclada, Eremocaulon, Guadua, Olmeca, Otatea.
  • Subtribe Hickeliinae:
  • : 9 genera: Cathariostachys, Decaryochloa, Hickelia, Hitchcockella, Nastus, Perrierbambus, Sirochloa, Sokinochloa, Valiha.
  • Subtribe Holttumochloinae:
  • : 3 genera: Holttumochloa, Kinabaluchloa, Nianhochloa.
  • Subtribe Melocanninae:
  • : 9 genera: Annamocalamus, Cephalostachyum, Davidsea, Melocanna, Neohouzeaua, Ochlandra, Pseudostachyum, Schizostachyum, Stapletonia.
  • Subtribe Racemobambosinae:
  • : 3 genera: Chloothamnus, Racemobambos, Widjajachloa.
  • Subtribe Temburongiinae:
  • : one genus: Temburongia.
  • incertae sedis
  • : 2 genera: Ruhooglandia, Temochloa.
33 genera: Acidosasa, Ampelocalamus, Arundinaria, Bashania, Bergbambos, Chimonobambusa, Chimonocalamus, Drepanostachyum, Fargesia, Ferrocalamus, Gaoligongshania, Gelidocalamus, Himalayacalamus, Indocalamus, Indosasa, Kuruna, Oldeania, Oligostachyum, Phyllostachys, Pleioblastus, Pseudosasa, Sarocalamus, Sasa, Sasaella, Sasamorpha, Semiarundinaria, Shibataea, Sinobambusa, Sinosasa, Thamnocalamus, Tongpeia, Vietnamocalamus, Yushania.

Distribution

Most bamboo species are native to warm and moist tropical and to warm temperate climates. Their range also extends to cool mountainous regions and highland cloud forests.
In the Asia-Pacific region, they occur across East Asia, from north to 50 °N latitude in Sakhalin, to south to northern Australia, and west to India and the Himalayas. China, Japan, Korea, India and Australia, all have several endemic populations. 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. 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, with a noticeable gap through the Atacama Desert.
Three species of bamboo, all in the genus Arundinaria, are native to the Southeastern United States. 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. Canada and continental Europe are not known to have any native species of bamboo. 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. In the United States, several companies are growing, harvesting, and distributing species such as Phyllostachys nigra and Phyllostachys edulis.

Ecology

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 include some of the fastest-growing plants on Earth, with reported growth rates up to in 24 hours. These depend on local soil and climatic conditions, as well as species, and a more typical growth rate for many commonly cultivated bamboos in temperate climates is in the range of per day during the growing period. Some of the largest timber bamboo grow over tall, and be as large as in diameter. The size range for mature bamboo is species-dependent, with the smallest bamboos reaching only several inches high at maturity. A typical height range covering many of the common bamboos grown in the United States is, depending on species. Anji County of China, known as the "Town of Bamboo", provides the optimal climate and soil conditions to grow, harvest, and process some of the most valued bamboo poles available worldwide.
Unlike all trees, individual bamboo culms emerge from the ground at their full diameter and grow to their full height in a single growing season of three to four months. During this time, each new shoot grows vertically into a culm with no branching out until the majority of the mature height is reached. Then, the branches extend from the nodes and leafing out occurs. In the next year, the pulpy wall of each culm slowly hardens. During the third year, the culm hardens further. The shoot is now a fully mature culm. Over the next 2–5 years, fungus begins to form on the outside of the culm, which eventually penetrates and overcomes the culm. Around 5–8 years later, the fungal growths cause the culm to collapse and decay. This brief life means culms are ready for harvest and suitable for use in construction within about three to seven years. Individual bamboo culms do not get any taller or larger in diameter in subsequent years than they do in their first year, and they do not replace any growth lost from pruning or natural breakage. Bamboo has a wide range of hardiness depending on species and locale. Small or young specimens of an individual species produce small culms initially. As the clump and its rhizome system mature, taller and larger culms are produced each year until the plant approaches its particular species limits of height and diameter.
Many tropical bamboo species die at or near freezing temperatures, while some of the hardier temperate bamboos survive temperatures as low as. Some of the hardiest bamboo species are grown in USDA plant hardiness zone 5, although they typically defoliate and may even lose all above-ground growth, yet the rhizomes survive and send up shoots again the next spring. In milder climates, such as USDA zone 7 and above, most bamboo remain fully leafed out and green year-round.