In a continuation of our growing bonsai trunks series, now the method known as the cut and grow and cut technique. This is a good method for species that backbud easily. Therefor, it is less suitable for pines etc.
The general idea
When you have a plant, roughly the size you want it to be, but way to thin for a bonsai, you basically take the growing tip out of the top of the plant, and let all the side-branches grow out. Every year or so you remove all branches before the spring-flush breaks. During the year, you continuously take out any new growth from the top of the plant, but you let the side-branches grow as much as possible. Naturally the plant -when in a growing box- is fed well, or even planted in full ground. This way all above-ground growth takes place along the trunk, increasing the overal girth of the plant, as well as the taper.
When the trunk has reached an acceptable girth, it is time to let the plant itself grow out from the top a little too. By doing this, any leftover cutmarks will heal, as the plant will increase girth over the whole length of the trunk. The bark will then grow over any of the smaller marks left by this technique.
This technique creates a trunk which has only small trimming marks. Most wounds created here will close over the course of two or three growing seasons, after which it is nearly impossible to tell how the trunk was grown.
This technique is much slower to develop a trunk than for instance the grow and cut technique. It only works for species that backbud easily.