I often am asked how straight the bamboo poles are. The poles that we use are monopodial (“running”) bamboo, as opposed to clumping / sympodial bamboo. The monopodial bamboos are like the ones seen in kung-fu movies such as Crouching Monkey, Hidden Panda, they grow upright like trees in a forest. Sympodial bamboos are bush-like, and naturally more crooked than monopodials.
Still, to get them perfectly straight during processing they are manually straightened, pole by pole. This is done by briefly heating the pole at the bend, and immediately bending it into shape before it cools. This ensures a perfectly straight pole.
A photo of the process below.