Prudence With Pruning



1. The ability to govern and discipline oneself by the use of reason
2. Sagacity or shrewdness in the management of affairs
3. Skill and good judgment in the use of resources
4. Caution or circumspection as to danger or risk
  (As it appears in the Merriam-Webster Dictionary)

Credit: Dylan Fawcett

Pruning is really what makes a bonsai a bonsai. It’s true that the definition of bonsai would implicate that the most important parts of it are the tree and the pot; but I think a large part, maybe the largest part, of bonsai is captured in the “miniaturization” of the tree. It’s really the aspect ratio of a bonsai that will allow anyone, having never seen a bonsai before, to differentiate one from a common house plant. So what is it that creates “bonsainess”? If I were to walk up to a complete stranger who has never heard of bonsai and gave him the description that “bonsai are miniature trees” would he be able to pick out the difference between a bonsai tree and a tree that is simply juvenile? My instinct is yes.

The “bonsainess” that a descriptive word like miniature is pointing to, has to do primarily with aspect ratio. The number of leaves, size of leaves, size of branches, taper of the trunk and branches, ratio of branch size to trunk size and ratio of leaf size to overall tree size are just some of the things that convey aspect ratio. A bonsai should look like a shrunken tree. When you compare bonsai to seedlings you can easily see that a seedling looks like a young tree but not a miniature tree. It’s this miniature appearance that makes a bonsai distinctive, and pruning is how we go about attaining this.

Look at the possible definitions of prudence above. Being prudent is really what pruning is all about.

In order to get a good grasp on pruning we have to govern ourselves and our actions on sound reasoning. In many cases you won’t have a second chance when it comes to the cutting decisions you are about to make with your tree, which is exactly why we need to be shrewd in our management of the trees growth.   Once you cut a limb, you can forget about ever getting it back. If we aren’t cautious of the risk involved in cutting we may even end up killing our trees.

Take just a moment to evaluate your limbs. If I remove the largest limb on this tree, what will be the effect? For starters, it will be gone. Secondly, the energy that was being spent by the tree to grow and sustain this limb will no longer be needed and it will be redistributed elsewhere. That’s a pretty good idea if we’re in the market for redesigning the tree! If we want growth in the branches we like, it’ll help to have the extra energy that is no longer needed by that large branch.

But hold on just a second. It also means that any potential energy that the leaves on that limb could have captured from the sunlight and given to the tree will also no longer be produced. When we combine these two concepts and apply our reasoning skills, we start to understand just part of how to make a pruning game plan.

When we take all the various pruning possibilities into consideration, we’re really just figuring out how the tree can best use its resources. To preface what I’m about to explain, let me just say that every tree is a little different. Understanding the major concepts in bonsai from a beginner’s standpoint requires a certain degree of generalization. So if you have your own ideas about the preferences of certain species, don’t get all fired up over what I’m going to say.

(Now with that out of the way) If you’re going to do any major cutting or you’re styling a tree you’re unfamiliar with, your best bet is to do it in the spring. If you’re working with maples or trees that respond similar to maples, making your cuts and wiring either just before the buds open or right after the first flush of the year has hardened are the best times for work. Most trees are similarly safe for working on in early spring. Spring the best time to work on the trees because the conditions are the safest. The tree is not dependent on collecting energy from the sun, like it would be in summer, and it is not under stress from the harsh elements like it would be in the winter.

It is possible to style any time of the year but it’s important to be aware of certain factors that will affect your choices. If you choose to style during the summer, you have to be very aware of how much you are taking off. If you remove 50% or more of the foliage, you will seriously jeopardize your tree’s ability to create and store the food it will need for the rest of the growing season and for new growth next spring. The heat of summer can also be harsh to some especially sensitive trees, and can have ill effects when combined with the stress of a hard pruning.

Pruning during the winter is also possible, but your tree will be vulnerable to the cold. During fall when the trees are getting ready for winter, they begin to build up high levels of sugars in their sap. If you’ve ever tried to freeze any kind of syrup, you realize that high levels of sugar inhibit its ability to freeze. The high levels of sugar act as a sort of anti-freeze which protects the tree from freezing even at temperatures below the freezing point of water. This also makes the sap flow through the branches and trunk much slower than in the spring and summer. If you cut the tree during this period of slow sap flow, it will take the tree longer to isolate the wound and reroute the internal channels that supply sap to the tree. That means that the chances of excess die-back, or the possibility that a cut at the end of a branch will kill more of the branch than just the area you cut, is increased.

The First Cut is the Deepest

There are obviously many factors to take into consideration and explore before you start styling. However, the 2 most important functions of an initial styling are:

1. Remove any branches that will not be used in the final design so that growth energy is not wasted.

2. Set the basic design which will be built upon in the coming growing seasons.

I think the second point is better elaborated on in the wiring section which I will address later. As for the first, when I started doing bonsai I really had a hell of a time with the initial styling of trees. I basically found it really difficult to decide which branches to cut and which ones to leave alone. I think the biggest problem for me, and perhaps you, is that the only guide we have is the awesome looking professional trees we see at displays and online. These trees are really important to our understanding of what good bonsai look like, and while these are the ultimate goal, we cannot initially style with those in mind. The reason these trees throw us off is because we try to style our trees with foliage pads to match the pro trees. This is bad because initially the creation of proper branching is much more important than making pads that look nice. We need a basis off of which we can eventually get there, and the path is a little simpler than you may think.

Cut the Fat

When you’re just learning bonsai it’s really important to have a fool-proof formula when you’re evaluating your trees. The first rule I will give you is the first rule that was given to me at a Korean Hornbeam workshop by Keiichi Fujikawa. Remove any branches that are growing directly up or directly down. I think that can even be expanded to any branches that are growing strongly up or strongly down. The branches I’m referring to are secondary branches, not the primary branches which grow from the trunk. The branches you’ll be eliminating are the ones that originate on the top or on the bottom of the primary branches.

There are a couple of logical reasons as to why we can unilaterally eliminate these branches and not worry about removing something that may be needed later. That is because they won’t be needed later. Branches that grow from the top or bottom of the primary branches will NEVER be able to be wired into a satisfactory position. You can try as hard as you’d like. You will either snap it in the process, or even worse, you’ll get it where you want it and be left with an ugly hump on the top or bottom of your branch. Secondly, branches growing in this manner have a tendency to be very strong and have almost no taper (gradual narrowing of the branch from its starting point to the tip). Bonsai are supposed to have a delicate branch structure and excellent taper. All of this goes back to that concept of aspect ratio we talked about in the Styling: the ground work section.

In order to create delicate branches with great taper, it is critical that we choose the weaker branches over the stronger ones. The elimination of the stronger branches will ultimately lead to balancing the growing power of the tree in favor of the weaker branches. Striking a good balance of energy throughout the tree is the only way to arrive at a professional looking tree.

Let’s take this idea we just discussed about removing strong branches that point up or down and add the next step. We can expand this idea to cover all branches which we would consider too strong. The primary characteristic we are looking for here is a branch that has very little taper. It will be extending from the trunk, be large in comparison to the other branches, and most importantly it will have a uniform thickness throughout. It’s important to note that the best taper comes from weak branches which gain size slowly over time. The size of a branch is set over the growing season and then built upon the next growing season. This is why a strong branch that grows quickly will have a uniform size. Once we’ve removed these from our tree, it will have the opportunity to support the weaker branches and sprout new branches that we may want to keep.

Standing Out

One final idea that you should grasp before styling your first tree is the idea of individuality of a tree’s parts. Every branch on you tree needs to occupy its own space. Congested branches make the tree look disorganized and unrefined. We combat this by establishing 2 simple rules that work together. The first rule is that no two branches should occupy the same horizontal or vertical space. By this I mean that if you were to locate the position where a branch emerges from the trunk, then draw a line around the trunk parellell to the ground, and a line straight up the trunk perpendicular to the ground, no other branches would be touching the line.

Credit: Dylan Fawcett at the National Bonsai and Penjing Museum

It’s very difficult to show the vertical lines in a 2D image, but the central idea is the same as the horizontal lines, only concerning where the branches emerge on the trunk in comparison to those above and below it. The lines I’ve drawn over the photo above cut through the point on the trunk where the branch emerges, not where the foliage pad is. The pads follow the same rules as the branches but add a 3rd dimension of individuality. We’ll discuss those later.

The second rule regarding this concept is that no 2 branches should be too close together (or too close to occupying the same level as discussed above). Basically we loose the “kept” feeling of bonsai if we have too many branches sticking out of one area. If you find your self with two branches emerging an inch apart on your tree, you have to choose. Combining the concept of balancing here will tell you to cut the stronger branch.

If you follow the rules I’ve laid out above, I guarantee you will end up with a great foundation for a bonsai. It may not look like a bonsai yet. It probably won’t even look pretty, but the steps we’re going to take next depend on the work we do at this stage. The quality of your tree depends on following the rules of cutting.


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