Everyone in arboriculture tells me that we should cut damaged roots cleanly. Arborist's reports always talk about cutting the roots off cleanly at the face of the excavation. Why? Is there any proof that cutting back roots to an artificial point is beneficial compared to leaving the torn stubs? Surely we're removing storage capacity and nutrients by trimming the roots back. I think this is just one of those 'conventional wisdoms'. Anyone think differently? It strikes me that if trees are resistant to root damage they will tolerate it regardless of whether root pruning is done well or badly. Liquidambars are one tree that really soaks up heaps of root damage - Planes are another. Any comments?
I don't know about this, but it would seem to me that clean cuts are preferable to tears. I think that is general practice for any kind of would on plant (or animal). If dead torn matter is left attached to the roots (or elsewhere), it might promote infection.