Bonsai growers know so many technical things about trees. People tend to think Bonsai is only for pot culture. Think Japanese gardens, full of beautiful trees growing in the ground. Whenever I have questions about trees, I always turn to experienced Bonsai growers. They do a lot of root trimming, pruning (in the ground) but know the right time and what and when not to cut. I am presently playing with bonsai on two trees growing on my property. Both are considered nuisance trees, so instead of cutting them down, I decided to train them to look good. One is a Golden Rain Tree, the other Ficus. I would still post your question to the forum even if your trimming is a wise idea. You might get more advice. Jane

That tree is obviously very well established and with numerous decades under its belt. While never a good thing, if those girdling roots were to be a concern, that concern would have manifested already with stunted growth and lack of foliage development and the tree would be already in decline. It doesn't appear to be suffering any of those conditions :-) I would guess at this length of time after planting, there are more than enough structural roots radiating out from the trunk to provide anchorage and with them all the fine feeder roots that support the tree with moisture and nutrients. If you were to peel back the sod and soil to expose the entire root system, I am sure you would find large roots extending well out beyond the tree canopy - I doubt the tree would have survived this long without them. There is nothing you need or should do at this point - the tree is self-sustaining. If you have questions about its structural integrity - the possibility that it could blow down in a storm - then you may want to have the tree examined by a certified arborist who is skilled in hazard assessment. This is not your average Joe Blow tree-trimmer but a highly trained tree professional. There is a BIG difference!!

your pic doesnt get bigger when i click on it ... so i cant really focus on it.. even if i put my nose on the screen.. lol .. the issue for me .... how much of the root mass would you be removing??? if this would take away 10% or less of the root mass.. who cares.. do whatever you want ... if in doing so.. you remove half the root mass ... i might suggest that would not be approved ... since on digging it up [it sounds like you moved it on your property.. rather than brought in a potted tree???] .. on digging it up.. you already cut off a lot of the root mass ... does that make any sense.. or should i try again ... i suppose roots dont blow in the wind.. hopefully.. lol ... and ergo.. dont really rub on each other to create a wound .. im not sure it matters with roots .... see pic for how a silver maple laid its roots on top of each other .. ken the pic isnt quite what i had hoped.. but hopefully you get my drift ...

Notice also that it came in a wire or plastic basket that is still present and intact - at least above the soil line - after 3 years. Cut through the worst of the girdling roots and pull them off or at least leave them with gaps so they can't repair themselves. And try to get as much as the basket off as you can, without damaging the rest of the root crown. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Planting-fact-sheet.pdf If you dig down (carefully) to discover pretty much the whole root system is going around in circles right next to the trunk you might consider replacement with a different specimen, that is not so badly deformed. This may take some looking, as even still quite small trees and shrubs may often have been left too long in bands or small pots at commercial production facilities. But at least with starter plants it may be more feasible to make significant corrections and have the plants come through them.