Is Bamboo a tree or grass ?
The Bamboo is one of the most fascinating plants on the earth but is Bamboo a tree or grass ? Indian Forest Act 1927 under section 2(7) has defined the bamboo as a tree ! The bamboos are a group of woody perennial plants in the true grass family Poaceae, subfamily Bamboosoideae, tribe Bambuseae. Some are giant bamboos, the largest member of grass family.
To a layman all bamboos look alike but actually there are more than 70 genera divided into about 1000 different kinds species in the world. Because of their large size these arborescent grasses are also called ‘elder brother of grasses’. Bamboos have age-old connections with the material needs of man and are fascinating to the artist, the poet, the craftsman and the scientist. Aptly called the ‘poor man’s timber’ bamboos are of great importance to the people of the East where they are found in greatest abundance and variety. Several Asian cultures, including that of the Andaman islands, believe thatHumanity has emerged from the bamboo stem. They are of considerable economic and high cultural significance in East Asia and South East Asia where they are used extensively in gardens, as building material, and as a food source.
Bamboos are the fastest growing woody plants in the world. Their growth rate (up to 60 centimeters (24 in.) a day) is due to a unique rhizome-dependent system, but is highly dependent on local soil and climate conditions.
The Bamboo in India
While 150 species are found in the Indian subcontinent, India alone accounts for more than 115. Spread over an area of 10 million hectares or 13 per cent of the total forest area of the country, perhaps the world’s largest reserves of bamboos consisting of over 115 species both wild and cultivated exist in India; areas particularly rich being the northeast region and the Western Ghats. The bamboos in India have a wide range of distribution and found in all parts of the country except in Kashmir valley.
As an understorey they form rich belts of vegetation in well-drained parts of tropical and subtropical habitats and grow up to 3,700 m in the Himalayas. The distribution of bamboos, however, has been greatly altered by human intervention and natural stands have at places been more or less cleared off for shifting cultivation. The other intervention comes from the paper industry which cuts or grows bamboos according to its needs.
Garden varietyThe structural foundation of the plant is the underground, segmented and condensed rhizomes which goes on propagating vegetatively. The arterial part (stem) is called the culm and several culms arising out of the ramifications of the rhizome are collectively called the clump. Bamboo-culms are branched at the nodes. The branches are sometimes spiny as in the case of Spiny bamboo. Depending on the species they may be mere shrubs with culms no thicker than a pencil as most hill bamboos are, or they may become giants reaching a height of 37 m and a diameter of more than 0.25 m as in the case of the Giant bamboo of Burma, which is cultivated at Dehra Dun and some other places. Whereas most of the bamboos are erect, quite a few are scramblers and even climbers, stretching over the crowns of tall forest trees.
Nearly all species are green when fresh but some like the pantropical Tiger bamboo are of a beautiful golden colour with green stripes or otherwise variegated. An occasional species has near black colour. Most species have hollow culms but some like the Male bamboo (so called because of its strength) – have solid culms.
Bamboo is the fastest-growing plant on Earth; it has been measured surging skyward as fast as 121 cm (47.6 inches) in a 24-hour period 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 meters (250 feet). Primarily growing in regions of warmer climates during the Cretaceous, vast fields existed in what is now Asia. Modern bamboos can only sustain their maximal growth rate for short periods of time.
Unlike trees, all bamboos grow to full height and girth in a single growing season of 3–4 months. During this first year the young shoots strike skyward supported by photosynthesis from the rest of the clump with no time to sprout their own branches and leaves. Over the next year the pulpy wall of each culm slowly dries and hardens, sprouting branches and leaves during the second year from juvenile sheathes that form from each node. Over the following year the culm hardens still further shedding its juvenile sheaths and commencing its life as 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, eventually penetrating and overcoming the culm so that by around 5 – 8 years depending on species and climate the culms begin to collapse and decay. This brief life means culms are ready for harvest and suitable for use in construction from 3-5 or 7 years.
Although some bamboos flower every year, most species flower infrequently. In fact, many bamboos only flower at intervals as long as 60 or 120 years. These taxa exhibit mass flowering (or gregarious flowering), with all plants in the population flowering simultaneously. The longest mass flowering interval known is 130 years, and is found for all 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, 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.One theory to explain the evolution of this semelparous mass flowering is the predator satiation hypothesis. This theory argues that by fruiting at the same time, a population increases the survival rate of their seeds by flooding the area with fruit so that even if predators eat their fill, there will still be seeds left over. By having a flowering cycle longer than the lifespan of the rodent predators, bamboos can regulate animal populations by causing starvation during the period between flowering events. Thus, according to this hypothesis, the death of the adult clone is due to resource exhaustion, as it would be more effective for parent plants to devote all resources to creating a large seed crop than to hold back energy for their own regeneration.A second theory, the fire cycle hypothesis, argues that periodic flowering followed by death of the adult plants has evolved as a mechanism to create disturbance in the habitat, thus providing the seedlings with a gap to grow in. This hypothesis argues that the dead culms create a large fuel load, and also a large target for lightning strikes, increasing the likelihood of wildfire. Because bamboos are very aggressive as early successional plants, the seedlings would be able to outstrip other plants and take over the space left by their parents.However, both have been disputed for different reasons. The predator satiation theory does not explain why the flowering cycle is 10 times longer than the lifespan of the local rodents, something not predicted by the theory. The bamboo fire cycle theory is considered by a few scientists to be unreasonable because, as argued by fires only result from humans and there is no natural fire in India. This notion is considered wrong based on distribution of lightning strike data during the dry season throughout India.
The mass fruiting also has direct economic and ecological consequences, however. 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, there are devastating consequences 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 increase, 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.
Woven Basket from Bamboos
Poor Man’s Timber
The number of ways bamboos enter into the diverse phases of human life is astonishing. It has been said that these giant grasses are one of those providential developments in nature which, like the horse, the cow, wheat and cotton, have been indirectly responsible for man’s own revolution. Bamboo is a material that is sufficiently cheap and plentiful to meet the vast needs of the human population – from the child’s cradle to the dead man’s bier.
Role of Bamboo
The qualities which make bamboo so versatile are the strength of culms, their straightness, lightness combined with hardness, range in size, abundance, , easy propagation, and the short period in which they attain maturity. The culms can be easily split with ordinary hand tools. In the humid tropics whole houses are built entirely of bamboo without using a single nail; huge suspension bridges made solely of canes and bamboos are marvels of indigenous engineering skill typical of tribal expertise. In fact there is no limit to the varieties of articles that can be made out of the bamboo.
Thomas Edison had used the carbonized filament of bamboo for his early electric lamps; the razor sharp peel has been, at times used in place of the surgical knife.
Chinese wood carving – late Qing Dynasty
Among the more sophisticated uses of the Bamboo are the manufacture of a large variety of writing papers, charcoal for electric batteries, liquid diesel fuel obtained by distillation, enzymes and media for culturing pathogenic bacteria from shoot extracts and the white powder produced on the outer surface of young stems for the isolation of crystalline compound similar in nature for female sex hormones. Tabasheer or banslochan, the fine siliceous matter deposited in the hollow stems of some species, has excellent properties as a catalyst for certain chemical reactions, though in the subcontinent it is prized as a restorative tonic and aphrodisiac.
Another aphrodisiac use, though nefarious one, is attributed to the rhizome of Rhino bamboo (D. Hamiltonii) which is an exact replica of a rhinoceros horn that fetches a fabulous price; only an expert perhaps can identify the imitation rhino horn from the real. Recently a new use of bamboo, ‘Bamboo reinforced cement concrete construction’, has been evolved where bamboos have been used as reinforcing material replacing steel in the construction of roof-slabs, beams, electric posts, etc.
Bamboo, the main diet of the Giant PandaBamboo are used for thatching and are also valued as fodder; elephants in particular are fond of it. The Giant Panda’s diet is entirely made up of bamboo leaves. Dried and matured leaves are also used for deodorising fish oil. Bamboo sheaths are used in lining of hats and sandals. As a popular ornamental, bamboo is used for hedges and in landscape gardening. It is valuable as a wind-break and is particularly useful for preventing soil erosion on account of its interwoven root system.
The shoots (new bamboo culms that come out of the ground) of bamboo are edible and most popular and relished food in Chinese and Asian Cooking. They are used in numerous Asian dishes and broths, and are available in supermarkets in various sliced forms, both fresh and canned version.The bamboo shoot in its fermented state (called khorisa) forms an important ingredient in the cuisine of Assam.In Indonesia, they are sliced thin and then boiled with santan (thick coconut milk) and spices to make a dish named 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. Zhúyèqing jiu is a green-coloured Chinese liquor that has bamboo leaves as one of its ingredients.Bamboo leaves are also used as wrappers for zongzi, a steamed dumpling typical of southern China, which usually contains glutinous rice and other ingredients.The empty hollow in the stalks of larger bamboo is often used to cook food in many Asian cultures. Soups are boiled and rice is cooked in the hollows of fresh stalks of bamboo directly over a flame. Similarly, steamed tea is sometimes rammed into bamboo hollows to produce compressed forms of Pu-erh tea. Cooking food in bamboo is said to give the food a subtle but distinctive taste.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 grounded to sand size particles to prepare a garnish known as “hendua”. It is also cooked with tender pumpkin leaves to make sag green leaves.In addition, bamboo is frequently used for cooking utensils within many cultures.
MedicineBamboo is used in Chinese medicine for treating infections. It is also used for healing. It is also a low calorie source of potassium. It has also been known for its sweet taste and good source of nutrients and protein. In Ayurveda, the Indian system of traditional medicine, the silicious concretion found in the culms of the bamboo stem is called banslochan. It is known as tabashir or tawashir in Unani-Tibb the Indo-Persian system of Medicine. In English this concretion is called “bamboo manna”. This concretion is said to be a tonic for the respiratory diseases. This concretion, which was earlier obtained from Melocanna bambusoides is very hard to get now and has been largely replaced by synthetic silcic acid. In most Indian literature, Bambusa arundinacea is described as the source of bamboo manna.
What is lucky bamboo?
‘Lucky bamboo’ is a popular plant, increasingly available in shops and stores. The plant is probably of West African origin. It is easy to maintain. It thrives without soil in a few inches of water, and requires only a little sunlight to grow. It is however not bamboo. It is Dracenia sanderiana, a member of the lily family.