Bamboo
Created | Updated Mar 5, 2008
Few people in the western world have had enough contact with tropical and sub-tropical clumping bamboo to appreciate how versatile and valuable it can be. Bamboo is the fastest-growing and most widely-used woody species in the world1. It is part of everyday life and culture throughout Asia, yet most of us remain ignorant of its value.
Approximately 40 million hectares of the Earth is covered with bamboo, mostly in Asia. About 200 million tonnes are harvested annually, for building, paper-making, furniture-making, food and dozens of other uses.
What Is Bamboo?
Bamboo is a giant grass: a sub-family (Bambusoidae) of the grasses (Gramineae) with tree-like or shrubby forms and woody stems.
The main structure of bamboo is made up of rhizomes2, aerial culms3 and branches. They are all formed of alternating series of nodes and internodes. Culms are hollow stems with rigid internal internodes, rather like a series of solid-ended tubes one on top of another. This is part of the reason for bamboo's great strength and its value as a construction material. Branches are formed at the nodes of the culm and leaves form on the branches.
There are two main types of bamboo: clumping (monopodial) and running (sympodial). Clumping bamboo is the most valuable in terms of its versatility of use and is therefore the main focus of this entry.
Running bamboo differs from clumping bamboo in so many ways that it can be regarded as a completely different group of plants. The most noticeable difference is that it is highly-invasive in nature. The rhizomes of running bamboo are usually long, solid or semi-solid underground canes that support a dense root system. These rhizomes develop buds at almost every internode and a single rhizome can produce many new culms and new rhizomes every year, because each bud develops into one or the other. All running bamboo grows happily in all climates and its invasive nature means that it either takes over, or has to be controlled. Structurally, running bamboo is inferior to clumping bamboo: the walls of the culms are thinner, weaker and more brittle.
Bamboo does not grow in width, like trees. When the young shoots emerge from the ground they maintain their original diameter throughout their life. However, young developing clumps of bamboo produce progressively thicker and taller culms each year. Culm heights vary from just a few centimetres to many metres high. They grow their entire height in one season and growth is completed in less than 12 weeks. Vigorous species in good conditions can grow at a rate of 40cm a day.
Culms can be straight or curving, green, yellow, brown, black, red, spotted or striped. Most are circular in section, although some are oval or almost rectangular. There are over 600 known species of clumping bamboo4.
Gregarious Flowering
Bamboo flowers irregularly. Some species flower annually, but only for a few years every 100 years or so5. When they flower they produce masses of seed, which is viable for just a few weeks. As a result, most of their propagation is vegetative - that is, takes place through rhizome separation. This may explain the phenomenon of gregarious flowering when the same species come into flower at the same time6 all over the world: they are all clones. This flowering cycle appears to be linked to a species-specific genetic time clock. Different species, however, vary in flowering frequency from 30 to 120 years.
The flowering process takes up to two years to complete and puts enormous strain on the plants. Many flowering plants die as a result.
The flowers are inconspicuous and fertilisation is achieved by wind pollination. Seeds are commonly the size of a grain of wheat and if they are fertile will germinate readily, but the short viability of seeds result in limited success.
Where Does Bamboo Grow?
Bamboo originates from the tropical and sub-tropical forests in a broad equatorial belt between 40° north and 40° south and up to an altitude of 3,000m. The main regions of distribution are China, Japan, South America, Africa, Southern Asia, Northern Australia and Central America. Most bamboo is grown domestically: households grow what they need. However, there are some plantations which provide construction materials for towns and cities in Asia.
Bamboo will grow equally well in shade as in full sunlight, although it grows stronger and straighter if in competition with other forest plants for light from above, producing perfect bamboo for structural use. Shelter from strong winds is essential as the combination of shallow root systems and great height make the plants susceptible to falling over. They thrive in damp soil, but will die if the roots are in permanent bog. For domestic cultivation, mulch and fertilisers yield good results.
Uses Of Bamboo
Bamboo has uses as a growing plant, as well as once it is harvested. It can provide hedging and stock fencing. It is used to stabilise slopes, as the fine web of shallow roots radiating from the rhizomes binds the soil surface.
Once harvested, however, the uses of bamboo are almost limitless and its importance has not been reduced by the introduction of modern plastic and metal substitutes. Bamboo is lightweight, hard, flexible and tough. It bends under heat. It can be drilled using a steel bit. It can be sawed using a fine hacksaw. It can be split by knocking a knife through the culm.
Bamboo has an extraordinary variety of uses. It can be used for almost every domestic and agricultural structure, implement and container, for food and drink, for fibres and for entertainment. The icing on the cake is that many people find it beautiful to look at.
Uses of Clumping Bamboo
Building and construction all over Asia: house foundations, flooring, walls, blinds, roof frames, scaffolding, shuttering and plumbing.
Bridges made from a combination of bamboo ropes and whole culms.
Utensils and implements, domestic and agricultural such as cups, pipes, rakes, brooms, ladders, carts, walking canes and furniture.
Bicycle frames: manufactured and used in Europe in the late 1800s.
Food: shoots are high in trace elements and vitamins and are a common ingredient in Thai, Chinese and Japanese food.
Uses of Clumping and Running Bamboo
Baskets: very widespread in Asia and used for all kinds of carrying container as well as for steam-cooking baskets.
Matting, screens, fences: often culms are split and used like basketry willow.
Ropes made by splitting culms into fibres, then twisting them.
Weapons such as bows, arrows, spears and blowpipes.
Kites, particularly in Japan.
Fishing poles and spears.
Seeds can be brewed into bamboo beer and sake7. They can also be used like wheat as a cereal.
Musical instruments, such as flutes and pipes.
Paper pulp: bamboo fibres are long and the leaves as well as the culms can be used.
Animal fodder: shoots and leaves are relished by ruminants, including pandas.
So What?
The variety of uses of bamboo, its extraordinary rate of growth, the ease with which it grows and the fact that its clumping nature enables a lot of it to be grown in a comparatively small area, make it a cheap, sustainable and efficient crop. It is the perfect crop for people who want to be, or have to be, as self-sustaining as possible.
Whilst bamboo is part of life in most areas of the world which support tropical and sub-tropical rainforests, the export potential has not been fully explored. Markets in the west are just beginning to open up and giant bamboo culms can now be seen in garden centres and interior design shops. Its use as architectural feature material is just starting. Cane furniture has been with us for a few years and there is scope for its further expansion.
Bamboo may never be an integral part of life in the temperate areas of the world, but it is an aesthetically-pleasing and sustainable alternative to wood, plastic and metal and it is a material which has not yet reached its potential worldwide.
Bibliography
Crawford, Martin: Bamboos, Agroforestry Research Trust 1997
Cusack, Victor: Bamboo Rediscovered, Earth Garden Books 1997
Janssen, Jules: Building with Bamboo, Intermediate Technology Publications 1995
