In this video, This Old House landscape contractor Roger Cook and certified arborist Matt Foti save a tree from mulch suffocation.
1. Use shovel to carefully remove all the old mulch that's piled up against the tree.
2. Use bypass loppers to cut out any drip irrigation tubing found on top of the root ball.
3. Next, use a compressed-air excavation tool to blast away any remaining mulch and soil to expose the root flare.
4. Cut away all up-growing roots with hand pruners.
5. Fill voids around the tree with topsoil. Be sure you don't cover the primary root flare.
6. Spread 2 inches of mulch around the tree, making sure to keep it away from the trunk.