The huge girth and dramatic taper on this powerful Satsuki azalea, were achieved primarily through the use of sacrifice branches. In fact, you’ll notice that some are still being employed to help thicken the primary branches. This photo is from The Magician: The Bonsai Art of Kimura 2, by Stone Lantern Publishing.
Single sacrifice branches and unsightly scarring
In energy balancing #3 we showed a juniper with a single sacrifice branch at the top. Single sacrifice branches are often used, especially to thicken trunks, and they can work quite well. However, one problem with using single branches is that, in order to be effective, they can get quite thick and can leave an unsightly scar when removed.
Many small sacrifice branches
One solution to the scarring problem is to use many small shoots as sacrifice branches. None need ever get so big that they leave a scar. This technique works particularly well on azaleas and other types of trees that put out a profusion of buds on old wood.
Before. This is what Master Kimura started with. Though you can see the beginnings of the powerful nebari and base of the trunk, the overall appearance isn’t up to much. Kimura cut off almost all the foliage in order better see what he was dealing with. With azaleas and other prolific budders, this isn’t a problem.
One year later. The profusion of shoots shows how easily azaleas bud on old wood. Kimura has already removed some shoots and left others as future branches and as sacrifice branches (sacrifice shoots might be a better term in this case). The little clumps of sacrifice shoots just above the soil, are being employed to thicken the base of the trunk.
Some time later (the original says one year after the photo just above, but I find that hard to believe; perhaps it’s a translation error). Now that the trunk is where he wants it, Kimura leaves selective shoots; some as future branches and some to help heal some large scars (another use of sacrifice branches). Also, as you can see, Kimura has decided that it’s time to start developing the apex.
If you want to see the entire process (there’s much more) on the development of this old Satsuki azalea, you might want to consider the book. Also, you might want to check out this profile and an interview with Masahiko Kimura at The Art of Bonsai Project.