I suppose I should shorten them all (when I separate them) to lower shoots so they can support themselves and to encourage backbudding? I think they are only upright at the moment because of the close planting and the low wall behind them although some of the trunks are getting quite sturdy.
I wouldn't chop them at Repot for a couple reasons.
I think all conifers transplant better with full foilage.
Giving them extra to do while trying to repair roots isn't the best.
The closeness hasn't allowed much light to penetrate, so any backbudding would probably prove leggy if anything, and without new buds you're on a short lifeline till them needles fall.
I don't know anything about radiata except they have one of the coolest names.
Also....of designing a proper forest......
I don't think you have enough prior information on these particular trees yet to begin making pruning moves to a forest.
I'd want to know the exact height of buds likely to emerge, which will relate to thickness, which will relate to chop height, which will relate to placement, probably a few more values I forgot, then ALL of this has to be in proportion to one another.
In short, it is impossible to make good decisions yet.
As an Idea to further understand....
You have a lot of trees.
I would guess you could seperate or otherwise pick through the outer more lit ones, and the interior less lit ones, and see they have values so different, they would each make their own good Forest, but would absolutely never work together, just do to properortions. (Will that pass as one word for proper proportions?)
It should because it needs a lot more emphasis on the whole.
It is difficult to properly proportionalize a single tree, more difficult when many of them must also be in proportion to each other.
If bonsai is a slow freight train....
Forests are slow freight trains where you know they will be robbed half way through the journey then all the product remade and reloaded and delivered still slow. No rush.
Sorce