When winter comes the leaves fall from deciduous trees making it much easier to assess the structure and ramification of your bonsai. The branches of a good bonsai should have plenty of sub branches and shoots to make it look like a real tree but if the shoots are a tangled mess the tree does not look its best and inner shoots will gradually die out.
How you prune will depend on the stage your bonsai is at but there are a few points that will help develop and maintain really good branches.
1. Long internodes.
An internode is the space between 2 buds or nodes (where there were leaves). The nodes are where new shoots or buds can grow, even after many years. Buds will rarely grow from where there are no nodes on the branch. Young and fast growing trees tend to grow shoots with long internodes, especially in vigorous spring growth. Later in the season growth is more compact with more buds and shorter internodes.
When we are new to bonsai we tend to be in a hurry to grow a tree and use any shoot to make a branch. My early trees were like this but I now see the bare areas along trunks and branches which were grown from shoots with long internodes. In some cases I have completely removed branches in order to grow them again from more suitable shoots. It would have been much better to have known how to grow good branches from the start.
This picture shows a shoot that has a long internode at the base. it might be ok to build a branch on a larger tree but not suitable for a more compact branch. Best option is to cut it off. More shoots will grow from the buds at the base and hopefully one will provide a better base for the developing branch.
After removing the shoot with a long internode.
2. Multiple shoots.
Most bonsai growers are aware that ‘bar branches’ are not desirable but few really know why. A bar branch is where 2 branches emerge from the trunk at the same height. Visually bar branches interfere with the flow. Our eyes momentarily can’t decide whether to flow left, right or on upward and this hesitation produces a sense of unease. Horticulturally the long term implications are far worse. Where multiple shoots occur the area thickens far more than the surrounding trunk or branch. This leads to local swelling and ‘reverse taper’ which also produces that sense of ‘not right’ in the aesthetic part of our subconscious.
It is therefore important to remove multiple shoots wherever possible.