Avoid Volcano Mulching
Information on How and Why to Avoid Volcano Mulching
Keep mulch away from tree trunks
Mulch that touches the tree trunk invites decay and pests and can kill the tree. The common effects of mulch heaped against a tree trunk include wood rot (likely to cause the tree’s death), girdling roots, and failure to develop a normal root flare (tree is less stable and more likely to fall during a storm).
Mulching is beneficial for trees when applied 2-4 inches deep to the drip line and away from the trunk — or by the “3x3x3 rule” of 3 inches of mulch, 3 inches from the trunk, in a circle 3 feet wide – so that wood chips, bark pieces, or other natural mulches form a flat donut with a tree in the center. The tree benefits from moisture retention (especially beneficial in warm weather), improved soil (as the mulch decomposes), and insulation against heat and cold.