Sorry no one answered you, but the idea won't hold water. Some trees are compartmental- you kill that root, you kill that side of the tree. Some bushes throw poisons around them which insure the fate of anything planted under them. There are always the main roots, but trees/bushes that survive in arid areas also have quick small roots that reach up and grab all available water. I have pine trees- well away from my raised beds, but, where you water, that's where they grow, so I clean the roots from my beds, containers, pots etc even when they aren't under a tree. Sometimes the roots grow straight up into a pot on the ground, so I won't grow anything needing deep roots near the other bushes. Good luck with your tries, tho
