Bonsai Technique - The Air Layer
What is an Airl Layer?
An Air Layer is a technique used in Bonsai to create a new tree out of a branch or trunk section of one tree. This has many applications across bonsai. One could take the end of branch and turn that into a bonsai or create a Shohin style tree. All artists have a slightly different method that they have grown comfortable with. Roughly every one uses a variation of this general method. I still make little adjustments depending on the type of tree and time of year.
How To Air Layer a Branch or Portion of The Trunk
In order to Air Layer a branch from a desirable tree or bonsai requires the removal of the bark from about an inch. This prevents carbohydrates from flowing down past the removal site. Yet it still allows water and mineral nutrients to flow upward to the leaves through the xylem. Thus, the tree will still get the nutrients it needs. The tree will create a new root system where the bark was removed. Root hormone can be used but is not necessary since hormones are stored at the removal site where roots will grow out. Some practitioners say root hormone can speed up the process.
We can place multiple air layers on a single tree. Having a mother tree and creating Bonsai out of appropriate branches is a common technique used in bonsai. It can take 50 years to develop the age we see in prize winning bonsai trees. Anything that can shorten this process is very useful.
I personally don't have much difference when using root hormone unless it's the very concentrated brands which are more expensive than they are worth.
After removing the bark and reaching the cambium of the tree apply hormone if desired. Next secure the bottom with a plastic bag to hold in the growing medium. I typically use sphagnum moss. Let the new root system develop and you can remove by cutting it at the base of the new root system.
It usually takes the new tree six to nine weeks to develop a complete root system.