Updated: Jan 7
When it comes to Bonsai Design there is the 1 Cardinal Sin that most people will agree with and that is having poor taper in a tree. Taper is very important to good bonsai design but can we fix it if it gets away from us? Lets take a look.
When we look at taper in bonsai we all first think of trunk taper, but branch taper is just as important, When we asses the taper in a tree we are looking for 3 points of taper which are
trunk taper ( bottom of the trunk thickest, top of the trunk thinnest with a gradual decrease in size on the way up with no swelling )
Branch Taper ( base of the branch where it emerges from the trunk is the thickest with the end of the branch being the thinnest, Each secondary or tertiary branch should be smaller again ).
Branch Structure Taper ( the lowest branch on the tree should be the thickest and all branches should decrease in thickness in order up the tree until you reach the apex which will have the thinnest branches ).
So now that we know what taper we are looking out for what are some common problems and ways to fix them or avoid them. The most common is inverse taper in the trunk or swelling which leads to golf balls in your trunk. This occurs when 2 or more branches are growing from the same location on a trunk. This is very common with Black Pine as they have a whirl pattern growth meaning they can have up to 4 branches growing from the same location, if you allow all 4 branches to keep growing you will eventually end up with a golf ball type swelling in that area which will give you inverse taper on your trunk. If this happens the only way to really fix it is to do some kind of shari or carving and depending on the type of species this can be undesirable. Its best to understand that if you have more then 1 branch growing from a section on a trunk you should make a choice and remove 1. If we go back to the rule of 2 this is easy to follow, we only ever have 2 shoots from any 1 location. In the instance of a trunk and a branch the trunk = 1 shoot and the branch = 1 shoot. We always count the trunk as 1. So if you had 2 branches coming from 1 location on a trunk that would = 3 shoots as the trunk is 1 and both branches are each 1. This is how we avoid welling both on our trunks and branches.
Now that same theory above can be applied to your branching except there is 1 slight change, if you have 2 shoots from 1 location on a branch ( opposite leaf pattern trees for example ). If the branch continues past the 2 shoots then you would reduce that area to being 1 shoot being the branch it self and 1 shoot being a secondary branch. But if the 2 shoots are on the very tip of the branch then you can keep both shoots. See the diagram below. If you branch taper gets away from you its hard to fix so the only remedy would be cutting the branch back and starting again so keep an eye on those new emerging shoots.
Ok so the last one is the branch structure taper. This is a very common problem for a lot of the species we work with as they are apically dominant so the top branches will get thicker while the lower branches get weaker and die off. we need to keep the top of the tree in check with pruning so we can avoid losing our lower branches but also to keep the branch thickness under control. if you do have a lower branch that is thinner then the one above it you can simply let the lower branch grow unchecked until it thickens and then cut it back and begin building the structure and taper on that particular branch, you will often see some trees in refinement with a longer lower branch because the artist is trying to thicken that branch to regain control of the branch structure taper.
I hope this has helped you understand Bonsai Taper and its importance in good bonsai design. We cant always avoid this especially on material we didn't grow ourselves. If you have collected material you can try and cover the inverse taper on a trunk with foliage if it is a conifer but it is difficult with deciduous trees or trees that have sparse foliage. But i hop e now you have an extra tool in your knowledge bank that you can fall back on to reduce the amount of flaws you material has in the earlier stages of growth by understanding a few techniques to prevent swelling and to help grow lower branches while keep the top ones in check.
Until Next Time, Enjoy Your Bonsai Journey.