Improving our Bonsai - Curves
Author - Mark Higgins
The previous article discussed some of the issues concerning taper in the trunk. This is not the only place taper should be evident and must also be present in the curves on the trunk and branches and the branches themselves. I guess the easiest way to describe taper in a Bonsai sense is going from bigger to smaller - thick trunk thinner trunk, big curves smaller curves, big spacing smaller spacing.
It is a lot easier to introduce the curve line in the beginning of our styling and this can be achieved very easily when propagating cuttings through selective pruning of shoots to extend the trunk line.
The position or angle that the cutting is planted at will also help to create movement. If we are using established stock or an existing bonsai then wiring and other techniques may need to be employed in order to improve or establish the curvature and movement in the trunk line. The curves should flow in a general side to side manner but not all on the same plane as we need to develop a 3 dimensional structure. If the curve line flows backwards and forwards then the full extent of the trunk line is not visible from the front. This is so important to remember when establishing the movement in the section between the base of the tree and the first branch (Tachiagari).
If the movement is strong and dramatic then this should be continued throughout the trunk line and even into the branches for that matter, but if it is gentle than keep the lines confined to this characteristic, in other words don't mix them.
Once again, taper is all important and as the curve lines ascend the trunk they should decrease in size. In regard to styling the trunk line, too often a tree is designed with only the now in mind and the future of the tree is not taken into account - use your imagination - think ahead. From the beginning, try to visualise the finished tree, in particular its finished height and the strength of movement in the trunk line that you want.
All trees grow and curves with little movement from the vertical line can eventually grow out. So if you are developing a tree from a cutting or seedling then it may be necessary to slightly over exaggerate the curve to start with, both in length and width in comparison to its overall size right now. However in saying this, don't go to the extreme and keep in mind that the end result must look natural.
Also keep in mind that as a tree increases in height, short tight curves will only need to become shorter and tighter in order to maintain taper as they ascend the trunk line. This can restrict not just the height of the tree but the entire structure, especially in relation to the placement of branches which will be covered further on. As previously mentioned, curves need to look natural. If we are using a clip and grow technique to develop curve lines in the trunk then you will notice that at first the line can be very angular. In most cases this will grow out and become more rounded with time but it is still worth keeping an eye on.
If reducing the height of a tree or undertaking heavy pruning then it is important to keep in mind that the angle of the cut will generally form part of the curve line. If the trunk line is curved then avoid having straight sections in the trunk. These areas will stand out on your tree and if allowed to develop can be very difficult to correct without a major operation. When introducing curves to material don't try to put too many curves in the trunk as this can cause problems with branch placement.
If we take a look at trees growing around us there is a strong tendency for branches to be positioned on the outside of curves. I'm not 100% sure why and perhaps someone can correct me if I'm on the wrong track but it would seem that the weight of a growing branch would pull the trunk in the direction of growth. As the tree develops branches further up the trunk line and they in turn pull the trunk in a different direction, movement is established and balance is maintained. Of course this would only be in an ideal growing situation and other factors such as wind and other forces of nature will have a bearing on the degree of curvature in the trunk. On the other hand there is the formal upright with no curve in the trunk line but if we look closely at these trees quite often there are a lot more branches than for example on an informal upright style. With the branches growing so close together and often in a spoked manner, there is very little opportunity for movement in the trunk line and consequently the close proximity of the branches appears to act as a brace for the trunk providing lots of support and keeping it nice and straight. Curve lines and taper are not just restricted to the trunk and should be evident throughout the tree. Too often you come across a well developed trunk line but there has been little or no regard for the design of the branches.
Taper, which is one of the most important characteristics of age must also be present in the branches as they ascend the trunk. They should decrease in thickness the further they are growing up the trunk line and any curves extending out into the branch should also show taper. One other important area of taper to focus on is the distance between each branch which should decrease as the branches ascend the trunk. We have previously spoken about how the thickness of branches can be addressed by controlling the growth of the branch and this needs to be a technique you become familiar with as the management of taper in the branches is ongoing. Taper in curve lines can be achieved or corrected with wiring or pruning techniques but unfortunately, more often than not, the branch structure is left very straight and this is one area we need to pay more attention to. Wiring can be a very tedious task but if we want our trees to move on to the next level then it is important that we address all the small details including getting that extra little curve in the branches. It can be an absolute pain but the end result is worth it. Once the main skeletal structure of your bonsai has been developed and you are happy with this aspect, then there is no real need to change it and it is then only matter of working with the outer growth which may need to be regrown and reshaped from time to time. A very old tree will appear to have a fine network of minor branches. In nature this is generally achieved from season to season and is more evident in deciduous trees especially during the winter dormancy. One of the best ways to view this network in evergreens is from below the branch and a well defined branch structure is one of the best aspects of any bonsai. A fine network of branches can be achieved through leaf pruning, pruning back the minor branches to two or three buds and also pinching out the new buds on growth as it develops.
Leaf pruning has two main outcomes :
it can reduce leaf size if undertaken in the latter half of the main period of growth, which in our case is generally after December and
it will force the tree to develop the axillary and adventitious buds which in turn will create new branches.
To achieve a fine network it is important to develop short inter nodal spaces. The first two or three leaves on any new growth is generally closer together but as a branch grows this spacing becomes extended. Therefore when pruning branches it is important to cut back to the first 2-3 leaves. This will help keep the inter nodal spacing short and also provide a much finer network of branches. Bud pinching has a similar impact in that when the apical bud is removed on a very new shoot it restricts the development of the stem forcing new buds to develop instead of extending the section of stem between each leaf. Just like the distance between branches on the trunk, as the branch structure increases, then taper should also be present with the distance between the fine branches decreasing as you move to the outer extremities of the branch. If we look closely at very old trees the branch structure is distinctly different to that of a young tree especially in the apical area, old trees have a very rounded apex where as the apex on young trees tends to be very pointed. In our designs, if we continue to grow the trunk line, then it is very difficult to get away from a pointed apex. At some point toward the apex we need to slightly diffuse the trunk line breaking it into several branches which when growing will have a more upward movement as opposed to those growing further down the trunk. Just keep in mind that the more branches you have in this area the risk of damaging the taper increases and regular thinning out will be required.
Of course, sometimes we already have in our collections or acquire material on which it is impossible to alter the Tachiagari or existing curve lines. In this case we need to select the front of our tree that provides the best perspective taking into account the Nebari, the Tachiagari, the existing curves and branch placement. It is highly unlikely that from any one angle all these aspects will be perfect and therefore we need to consider that :
the widest point of the Nebari should be visible from the front
the Tachiagari should generally move from side to side
the curve lines should be visible from the front in other words not curving backwards and forwards
the selected front should display the best taper in the trunk line
the trunk line should be three dimensional and
there is a natural taper in the branches as they ascend the trunk.
I hope that you have been taking more notice of the trees growing around you since these articles were introduced. If we continue to look at trees and identify the characteristics of age then we can refer these back to our bonsai and achieve better results and a greater satisfaction. One thing we need to keep im mind at all times is maintaining a naturalness to our designs and while something may look very artistic with lots of twists and loops in the trunk and branches, just ask yourself would the tree really grow like that.