Protecting Tree Trunks When Building a Raised Bed

Soil or mulch against a tree trunk causes bark rot, insect entry, and eventual decline. A 14-inch raised bed around a 20-year-old maple requires trunk protection.

Protection Methods

• Build a stone or metal collar (tree ring) 12–18 inches from trunk, leaving the root flare exposed.
• Ensure the bed width is minimal (8–10 ft diameter) to avoid root zone suffocation.
• Use porous fill (not clay) if covering large root areas.

Critical Warning

Covering >20% of the root zone with 14 inches of soil can kill a mature tree over 3–5 years. Keep the bed small and the trunk clear.