It would be a great mistake to train this tree, using Japanese Black Pine (or Red Pine) techniques.
Japanese Black pine is a low elevation tree, that has a very long growing season. Because of the long growth season, it has multiple growth flushes. It grows large candles, and if you cut those down before the end of summer, it grows another flush of candles. If you cut the candles earlier, you can even have more than two flushes of growth, especially if you live in a warmer climate.
Pinus contorta has a different growth habit. Because of the short growing season, it does not have the capacity to continuously push out new growth. So, I would treat it like the Japanese White Pine. This means no complete candle removal. You have to waint until the new growth hardens, and then remove PART of the new growth, thus leaving some new growth on it. If you cut off the entire new growth, and don't leave any of it, you will exhaust the tree and possibly kill the branch. Instead of encouraging back-budding, you put the tree into a constant low-energy state, where it barely survives.
So, if you want this tree to thrive, you need to keep on as much new growth as possible, while selectively prune certain branches, to encourage back-budding.
Japanese Black Pine can take a lot of abuse, because it is a very vigorous tree. This one can take much less of it.
BTW, I do not own this species, so I am NOT talking from personal experience. But I am very interested in training various species of pines, so I am trying to learn about them as much as possible. So, I am stating the teachings of those who work with P. Contorta and other species with similar growth habits.
This is the problems we are having here in North America, when it comes to bonsai. We have plenty of ideas, but we did not yet develop standardized techniques for all these native pines that we can collect. I know that some veterans have a vast kowledge about these pines, and collect and cultivate them successfully, but the general bonsai hobbyist has no idea how to treat them.
The Japanese have developed standard techniques for each pine species they grow. You can find those techniques in every bonsai book. Here in America, we aren't that far down the line yet. We should have books written on all the native pines, and easy-to-understand standard techniques on each of them. But we don't. And this is a HUGE limitation for us. I know that we have a tiny Ponderosa book...that very few people know about. But that's about it.
So, by and large, WE HAVE NO IDEA what to do with these wonderful trees.
We don't even have a Mugo book, for goodness' sake. Neither we have a Redwood, or a California Juniper book, which is beyond comprehension. We have a long way to go, before we start understanding how to grow these trees. We can, of course, keep them alive and reasonably healthy, but that is way to little. When doing bonsai, we need to keep these trees in their most vigorous and radiant state, because that's when they respond to bonsai techniques. "Reasonably healthy" will not cut it, and only leads to failures.
Anyway, enough of my rantings....
