Tayo Nishiki White Pine from nursery soil to bonsai mix

[coachspinks]

I bought this little pine from Conifer Kingdom last year. I like to practice on new to me species before investing in better versions. This one is a little better than expected. So many nursery pines have straight trunks with whirls and awful grafts. The pictures aren't great but it does have decent movement in the trunk and a number of branches to choose from. The graft is also better than a lot that I have seen. it is also not root bound. My question, when I repot it into bonsai mix, how much of the nursery soil do I remove? I don't anticipate cutting a lot of roots off but how much is too much and how much is safe? I know what I would do with a deciduous tree but not a pine.

 

[Wires_Guy_wires]

It looks grafted on strobus and my experience with strobus is that they take about every amount of abuse. Very difficult to get them to grow bark though.
But the heavy abuse in strobus.. That doesn't mean the top half JWP agrees.

I'd go with a safe approach and maybe do a half bare root.

If you're going to cut pine roots, it's hard to tell from the outside of the pot what the status is. If the pot is entirely full of roots, even throughout the soil, you're safe if you remove half.
If the pot isn't full of roots, and the soil isn't either, consider not repotting and just watching your watering for a year. Instead of raking the soil out, you could also use a soft stream of water. This is way less damaging.