When trees are growing quickly, it’s not uncommon to find wire marks along the trunk.
Wire marks above the first branch
For young trees early in the development phase, it’s not much of a problem when the wire cuts in at the base of the trunk. Cut marks cause swelling and swelling near the base of the trunk can be a good thing.
If, however, the wire cuts in higher up along the trunk, the resulting swelling can cause reverse taper.
Depending on the available branches, there are three basic approaches we can take to reduce the impact of the swelling.
- Thicken the whole trunk, from top to bottom
- Focus on thickening the section below the scars
- Remove the section with scars
Here’s how these options might play out with the present tree.
If I want the trunk to become 2-3″ in diameter near the base, the swelling caused by the wire marks will disappear long before the trunk reaches that size. I can let the new leader and sacrifice branches grow freely.
Option 1: let new leader (at top) and sacrifice branch develop freely
If I want the lowest part of the trunk to be thicker than the section with wire marks, I can let the lowest branch grow freely for several years. This will thicken up the lower section while having no effect on the rest of the tree.
Option 2: let the lowest branch grow freely to thicken the first section of the trunk
If I want the trunk to remain thin, I can remove the section with wire marks and use the first branch to become the new leader.
Option 3: remove the section of the trunk with wire marks and use the first branch as the new leader
About this (Occasional) Series
Over the years I’ve written a lot about basic approaches to developing bonsai – especially pine bonsai. Although I have fairly specific instructions for the first few years, the instructions tail off somewhat after that. The reason is two-fold.
For starters, I don’t have a lot of pines between 5 and 13 years old. As I do, I’ll write more about them.
More importantly, the recipe gets a bit fuzzy after 3-4 years. I tend to address specific situations during these middle years rather than execute step-by-step plans.
Some topics, including the present one, may seem obvious – especially to experienced growers. My intention is less geared toward demonstrating novel solutions and more focused on presenting the options I consider when working on young trees.
Many of the examples will feature black or red pines, though I hope for most of the topics to apply equally well to other varieties.
Let me know if any of this sounds useful or if these tips are best left in the workshop. Am looking forward to hearing what you think!