Larix laricina tree that I grew from seed.
I may have kept it too wet at the base, bottom watering, because of the last few years have been so dry.
Just noticed this season when adding mulch around the tree.
The errant root appears to be growing from right to right to left in the picture and the left end appears to just go straight away from the tree with no circling back that is evident.
I think it comes from underneath somewhere under the roots on the right.
The root it goes over (center) doesn't seem to be bothered with it and that root goes down at more of an angle, into the ground, so it may not be getting much pressure from the errant root and doesn't appear to be gouging into that root.
The tree seems very stable and whether or not it would make a difference cutting it off, I don't know.
Tamarack may just be a little on the wild side when it comes to roots, after all they grow in very wet environments.
What would you do? :-)
I dug a little more but the root appears to go down below the rest of the roots.