On one of my most used pathways, there is a “wall” of bamboo providing a privacy screen between a house and a busy street. It does the job well. The thick growth appears to be eight to 10 feet tall and is impervious to prying eyes. My only other experience with bamboo is feeding it to a koala bear at a zoo in Australia, seeing it in paintings or objects d’art in interior design and walking on sturdy and ecological bamboo flooring. I also saw it used for scaffolding around a building in Singapore.
According to Wikipedia, Bamboos are evergreen perennial flowering plants in the subfamily Bambusoideae of the grass family Poaceae. The word "bamboo" comes from the Dutch or Portuguese languages, which probably borrowed it from Malay.
Bamboos include some of the fastest-growing plants in the world, due to a unique rhizome-dependent system. Certain species of bamboo can grow 36 inches within a 24-hour period, at a rate of almost 1 1⁄2 inch an hour, a growth around 1 inch every 40 minutes. Giant bamboos are the largest members of the grass family. This rapid growth and tolerance for marginal land make bamboo a good candidate for afforestation, carbon sequestration and climate change mitigation.
Bamboos are of 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 versatile raw product. 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.
Distribution
Most bamboo species are native to warm and moist tropical and to warm temperate climates. However, many species are found in diverse climates, ranging from hot tropical regions 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 14,000 feet. Bamboo is also native through Central America and Mexico, northward into the Southeastern United States. Canada and continental Europe are not known to have any native species of bamboo. As garden plants, many species grow readily outside these ranges, including most of Europe and the United States.
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 Henon and Moso.
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, though, 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, depending on both the species and the soil and climate conditions. Some can send out runners of several meters a year, while others can stay in the same general area for long periods. If neglected over time, they can cause problems by moving into adjacent areas.
Unlike all trees, individual bamboo culms or above-ground stems 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 two–five years (depending on species), fungus begins to form on the outside of the culm, which eventually penetrates and overcomes the culm. Around five–eight years later (species- and climate-dependent), 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 can survive temperatures as low as −20 °F.
Mass flowering
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, 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 130 years, and it is for the species Phyllostachys bambusoides. 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. 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. This mechanism — as well as the evolutionary cause behind it — is still largely a mystery.
The huge increase in available fruit in the forests often causes a boom in rodent populations, leading to increases in disease and famine in nearby human populations. For example, devastating consequences occur when the Melocanna bambusoides population flowers and fruits once every 30–35 years around the Bay of Bengal. The death of the bamboo plants following their fruiting means the local people lose their building material; and the large increase in bamboo fruit leads to a rapid increase in rodent populations. As the number of rodents increases, they consume all available food, including grain fields and stored food, sometimes leading to famine. These rats can also carry dangerous diseases, such as typhus, typhoid and bubonic plague, which can reach epidemic proportions as the rodents increase in number. The relationship between rat populations and bamboo flowering was examined in a 2009 Nova documentary “Rat Attack.”
Flowering produces masses of seeds, typically suspended from the ends of the branches. These seeds give rise to a new generation of plants that may be identical in appearance to those that preceded the flowering, or they may produce new cultivars with different characteristics, such as the presence or absence of striping or other changes in coloration of the culms.
Several bamboo species are never known to set seed even when sporadically flowering has been reported. Bambusa vulgaris, Bambusa balcooa and Dendrocalamus stocksii are common examples of such bamboo.
Animal diet
Soft bamboo shoots, stems and leaves are the major food source of the giant panda of China, the red panda of Nepal and the bamboo lemurs of Madagascar. Rats eat the fruits as described above. Mountain gorillas of Central Africa also feed on bamboo and have been documented consuming bamboo sap which was fermented and alcoholic; chimpanzees and elephants of the region also eat the stalks.
The larvae of the bamboo borer of Laos, Myanmar, Thailand and Yunnan, China feed off the pulp of live bamboo. In turn, these caterpillars are considered a local delicacy.
Bamboo cultivation and harvesting
Bamboo cultivation in South, South East Asia and East Asia stretches back thousands of years. One practice, in South Korea, has been designated as a Globally Important Agricultural Heritage System. 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.
Bamboo used for construction purposes must be harvested when the culms reach their greatest strength and when sugar levels in the sap are at their lowest, as high sugar content increases the ease and rate of pest infestation. As compared to forest trees, bamboo species grow fast. Bamboo plantations can be readily harvested for a shorter period than tree plantations.
Leaching
Leaching is the removal of sap after harvest. In many areas of the world, the sap levels in harvested bamboo are reduced either through leaching or postharvest photosynthesis. For example:
· Cut bamboo is raised clear of the ground and leaned against the rest of the clump for one to two weeks until leaves turn yellow to allow full consumption of sugars by the plant.
· A similar method is undertaken, but with the base of the culm standing in fresh water, either in a large drum or stream to leach out sap.
· Cut culms are immersed in a running stream and weighted down for three to four weeks.
· Water is pumped through the freshly cut culms, forcing out the sap. This method is often used in conjunction with the injection of some form of treatment.
In the process of water leaching, the bamboo is dried slowly and evenly in the shade to avoid cracking in the outer skin of the bamboo, thereby reducing opportunities for pest infestation.
Durability of bamboo in construction is directly related to how well it is handled from the moment of planting through harvesting, transportation, storage, design, construction and maintenance. Bamboo harvested at the correct time of year and then exposed to ground contact or rain will break down just as quickly as incorrectly harvested material.
Culinary
Although the shoots of bamboo contain a toxin taxiphyllin that produces cyanide in the gut, proper processing renders them edible. They are used in numerous Asian dishes and broths, and are available in supermarkets in various sliced forms, in both fresh and canned versions. The golden bamboo lemur ingests many times the quantity of the taxiphyllin-containing bamboo that would kill a human.
The bamboo shoot in its fermented state forms an important ingredient in cuisines across the Himalayas. In Assam, India, for example, it is called khorisa. In Nepal, a delicacy popular across ethnic boundaries consists of bamboo shoots fermented with turmeric and oil and cooked with potatoes into a dish that usually accompanies rice.
In Indonesia, they are sliced thin and then boiled with santan — thick coconut milk — and spices to make a dish called gulai rebung. Other recipes using bamboo shoots are sayur lodeh (mixed vegetables in coconut milk) and lun pia (sometimes written lumpia: fried wrapped bamboo shoots with vegetables). The shoots of some species contain toxins that need to be leached or boiled out before they can be eaten safely.
Pickled bamboo, used as a condiment, may also be made from the pith of the young shoots.
The sap of young stalks tapped during the rainy season may be fermented to make ulanzi — a sweet wine — or simply made into a soft drink. Bamboo leaves are also used as wrappers for steamed dumplings which usually contains glutinous rice and other ingredients.
Pickled bamboo shoots are cooked with black-eyed beans as a delicacy in Nepal. Many Nepalese restaurants around the world serve this dish as aloo bodi tama. Fresh bamboo shoots are sliced and pickled with mustard seeds and turmeric and kept in glass jars in direct sunlight for the best taste. It is used alongside many dried beans in cooking during winters. Baby shoots of a very different variety of bamboo native to Nepal is cooked as a curry in the hilly regions.
In Sambalpur, India, the tender shoots are grated into juliennes and fermented to prepare kardi. The name is derived from the Sanskrit word for bamboo shoot, karira. This fermented bamboo shoot is used in various culinary preparations, notably amil, a sour vegetable soup. It is also made into pancakes using rice flour as a binding agent. The shoots that have turned a little fibrous are fermented, dried and ground to sand-sized particles to prepare a garnish known as hendua. It is also cooked with tender pumpkin leaves to make sag green leaves.
In Konkani cuisine, the tender shoots are grated and cooked with crushed jackfruit seeds to prepare kirla sukke. Konkani is an Indo-Aryan language spoken by the Konkani people along the western coast of India.
The Indian state of Sikkim has promoted bamboo water bottles to keep the state free from plastic bottles. The plastic bottles left behind by tourists prompted the promotion.
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