Most Japanese Black Pine need to be cleaned up yearly to reduce the density of the needles so that light can reach each of the branch tips evenly, enabling even growth. I had worked on this particular tree the past summer, decandling most of it, but leaving some of the weaker buds to grow out and effectively allowing them to become much stronger compared to the branches that were decandled. I knew that I'd have to work on the tree come fall because it would be too dense to leave for the entire winter without losing some of the important interior growth.
What started as a 4-hour long needle pulling session soon turned to some touch-up of the wiring (If you give a mouse a cookie....) and branch positions. Mature black pine need to be touched up at least every couple years, or completely rewired every three years. Even with decandling slowing the growth of the tree, the branches still manage to make short extensions; before long you’re looking at a lot of vertical branchlets rather than the beauty of the needles surrounding a dormant bud.
Pulling needles. Against the white background you can see almost no light penetrates completely through the tree. Without thinning, the lower and interior buds will become weak.
Needle pulling how-to: start from the top and work downward, allowing needles that you have dropped to be cleaned off as you go.
After pulling most of the old needles, some are still left on the lower branching to increase its strength relative to the top. The tree is still too dense overall; adjusting the wiring and removing long and clumped growth is the next step.
The amount of time and wire needed to work on larger trees isn’t trivial. I used about a half of a roll of #16 wire on the fine branching.
December, after completing work on this tree.
From the right side.
From the back.
I’ve owned this tree for nearly twenty years, almost as long as I’ve been doing bonsai. For a more complete history with photos you can see this thread on Bonsai Nut. It's definitely come a long way, as have I!
Reworking the tree each fall is really not absolutely necessary; I just find it immensely rewarding to have a few detailed bonsai trees in my garden at all times.