Bamboo

Bamboo

Bamboos are one of the most useful plants on earth. They grow fast and their strength-to-weight ratio is impressive. Their canes are easy to lash into quick-and-dirty infrastructure.

Peculiarities of bamboo timber

Bamboo wood splits easily vertically; this is both a problem and an opportunity. Bamboo timber can not be nailed easily because of its tendency to split, but it can be joined other ways. Because the culms are usually hollow (and even when not hollow, soft and pithy inside), bamboo timber only comes in round or arc shapes.

Bamboos are not rot-resistant. The timber needs to be protected from contact with soil, and in tropical countries does not hold up well to direct exposure to the elements.

Range and tolerances

Bamboos occur naturally on the Gondwanic continents: Africa, Australia, South America, and Asia which contains the Gondwanic subcontinent of India. There are a few species of Bamboo native to North America, which probably cam up from South America. Europe has no native bamboos, but several species are cultivated there in gardens.

Bamboos have climactic tolerances from equatorial rainforest to temperate climates with cold winters and warm summers. Their effective limit in terms of cold tolerance is roughly -28C/-20F. Most bamboos prefer climates that are either humid and rainy year-round, or at least during the growing season. There are American bamboos that tolerate semi-arid climates and a few that are adapted to dry-summer, wet-winter Mediterranean climates, but none that are very coldhardy; cold dry climates preclude bamboos.

Bamboos are tolerant of soil but prefer moist, rich soil.

Most timber bamboos require full exposure to the sun, and tend to die off when taller trees invade their territory. Some of the smaller species grow in the understory and some are extremely shade-tolerant, which is rare among grasses (bamboos are gigantic grasses). A few South American bamboos can start in the understory and attempt to aggressively take over the canopy.

Major divisions by type

Bamboos can be roughly divided into two kinds, "pachymorphs", also called "clumpers", and rhizomous species, also called "runners". This is not just a botanical distinction, but also a division according to culture, climactic adaptability, and use.

Pachymorphs

Pachymorphs do not have rhizomes; instead each new shoot branches off the last one. The shoots, called "culms", tend to grow close together in dense clumps. Lacking extensive underground rhizomes, the pachymorphs are mostly tropical species with no tolerance for cold. The exceptions are a relatively few mountain species that tend to be too small to use for timber. Although they tend to live in the tropics and subtropics, some of these montane species are from such extremely high elevations in South Africa and the Himalaya that they are among the most coldhardy bamboos.

Pachymorphs tend to have bitter shoots. They can be and in fact are eaten as food in tropical countries, but there is not much flavor left after leaching out the bitterness.

What pachymorph bamboos are good for is timber. Their culms are relatively straight, thick-walled, and don't taper too fast.

Some of the smaller pachymorphs are useful for paper. Their leaves and twigs can be ground to make pulp for paper production. At one time this was India's primary source of paper; it is still used but has been supplemented with tree-wood paper.

Aside from climactic limitations, the pachymorph bamboos are easy to cultivate, because they stay in nice, neat clumps that are easy to manage. Distance from the center of the clump helps the farmers keep track of the age of the culms, which is important for harvesting them at their peak strength.

Rhizomous bamboos

Rhizomous bamboos tend to live in cooler climates and higher latitudes than pachymorphs. That's probably because their rhizomes are capable of surviving freezes that would kill the culms--and then can regenerate again. It might also be because over time, their rhizomes travel significantly faster than the shoots of pachymorphs.

The wandering of their rhizomes makes them problematic for containment, but there are ways to handle this such as rhizome barriers and regular destruction of errant shoots. One way to put excessive shoots to good use is to eat them when young and tender, very much like Asparagus. Shoots of the genus Phyllostachys are the tastiest and sweetest, and the kind most harvested as food.

Although tropical pachymorphs are preferred for timber, where it is too cold to grow them, the timber of some of the larger Phyllostachys is used the same way. The disadvantages are that the culm walls are thinner (some cultivars have particularly thin culm walls making them very poorly suited for timber) and the culms taper faster. The best uses for the wood of Phyllostachys are making any one of thousands of smaller household items such as chopsticks, cups, bowls, whisks, and so on, and using suitably sized culms as poles for garden stakes and other simple structures for staking tomatoes, beans, and other crops that require support.

Some rhizomous bamboos with short culms and big leaves, such as Indocalamus, are used for wrapping food, just as some cultures would use paper, wax-paper, or aluminum foil.

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