Help with Trident Root Prune

[one_bonsai]

Not happy with the root system. I'm thinking of cutting off the two thick roots and encouraging the finer roots to grow in their place, but not sure.

 

[leatherback]

@Shibui is the right person for this thread.
In my opion, yes, you would need to get rid of these thick roots, and I would do this in later winter. But as said.. Wait for Shibui to come in. He grows these for bonsai sale in Australia and knows them very well.

 

[Shibui]

Looks like there's more problems than a couple of thick roots. The roots on the far side look dead to me so there's already a problem here. Chopping those last 2 roots might just finish this tree off for good.
At second glance I can see 1 small live root round that other side so maybe the tree is recovering from whatever problem killed those others?

At this stage I would be reluctant to chop those 2 healthy roots right back. It would be a different matter if there were other roots the tree could rely on while new roots grew but there's not much.

I have 2 suggestions:
1. Longer term but safer: Leave the roots alone this winter and get the tree healthy through next summer then chop if everything is doing better next winter.
2. Quicker but more risk: Chop the strong roots by about half of the old section. If it survives that the lack of roots should get some new roots growing nearby. Make sure the roots are well covered with potting mix through summer. Roots cannot grow if they dry out each day.

 

[one_bonsai]

I have 2 suggestions:
1. Longer term but safer: Leave the roots alone this winter and get the tree healthy through next summer then chop if everything is doing better next winter.
2. Quicker but more risk: Chop the strong roots by about half of the old section. If it survives that the lack of roots should get some new roots growing nearby. Make sure the roots are well covered with potting mix through summer. Roots cannot grow if they dry out each day.

What about starting a new root system with a ground layer using a tourniquet?

 

[Shibui]

What about starting a new root system with a ground layer using a tourniquet?

That should work provided the trunk is alive right round. Need to check to find out what has killed those other roots.
A ground layer will probably give better results than just chopping roots back but, again, you'll get far better roots on the layer if the tree is strong and healthy.

I spent some time root pruning more tridents from the grow beds - some smaller, some larger.

Here are just a few of today's trees:

 

[one_bonsai]

Need to check to find out what has killed those other roots.

Not sure I'll be able to find out why those roots died.