Density is a key concept in bonsai. We want young trees to develop good density. With mature trees, we aim to maintain density. Density, it seems, rarely takes care of itself.
Some of the young pines I’m developing have been decandled for the past several years. This has dramatically increased the trees’ density.
Dense foliage on 12 year-old black pine
If such density were maintained throughout the year, interior branches would quickly die out and no new shoots would appear to take their place. Without interior shoots, maintaining the current silhouette would not be possible.
The best way to keep interior shoots happy and encourage new buds is to provide as much light as possible in the tree’s interior. Branch cutback and needle-pulling are the primary vehicles for achieving this.
Branch cutback is the art of creating attractive and sustainable branch structure. Needle-pulling is more straightforward. By removing needles we reduce foliage density – good for letting light into the tree’s interior – and also reduce the tree’s ability to produce food – good for producing refined growth.
The best time of the year to pull needles on black or red pines is when the needles are mature – fall through early spring. For trees that have been decandled, needles can also be removed at decandling time.
After decandling this exposed-root pine, I began removing needles from strongest shoots.
After removing extra needles from the tree’s apex
In most areas, I left between 5-7 pairs of needles. The very bottom branch, however, is significantly weaker than the others so I opted to not decandle and removed very few needles.
Low branch after removing a few needles
Removing needles makes it easy to see the structure of the tree. This is one reason why pines are often wired after they are decandled.
The other reason decandling time is great for wiring pines is that the resulting summer growth will all point upward. This can give pines a natural feeling that’s hard to accomplish with wiring alone.
After decandling and needle-plucking
The window during which pines can be wired after decandling is short as new shoots can appear within a week or two of decandling. Once these new shoots appear, great care must be taken when wiring to avoid damaging new buds. For this reason, when summer buds appear it’s best to postpone wiring until fall at which point the summer foliage will be mature.
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