I am about to try my first air layer. I have read the procedure a hundred times. I thought I was ready until I was doing some final reading and come across accounts of "may not have cut deep enough" and "did I cut too deep". So how deep do I cut? I will be doing this on a Trident, for this specific instance. Every book I have read says remove the bark or cut to wood. This would insinuate removing all cambium. But we need to leave the part that still carries water upward. So if I remove bark and insure that there is no green left, how do I know it's right? I remember there being a bonsai site that showed a low air layer essentially to accomplish a new root base. They said they cut an 1/8 in. deep ring just to make sure they would not have it bridge back. What am I missing here?