Removing Fill Soil from Mature Live Oaks: Expose the Root Flare

Two feet of fill soil + lava rock over live oak roots for an unknown period = **chronic stress**. The **root flare (trunk flare into first roots) must be visible and exposed**.

Action: Excavate to Flare Immediately

1. **Carefully remove** soil/rock down to the **natural flare**.
2. **Hand tools only** near roots—air spade ideal if available.
3. **Do not damage roots.** Cut circling/girdling roots cleanly if found.
4. **Grade away** from trunk for drainage.
5. **Mulch 2–3 in.** (not on trunk) over exposed root zone.

Prognosis

• **If flare was buried recently (months):** Good recovery likely.
• **If buried years:** Some dieback already occurred; recovery slower, partial.
• **Monitor** for borers, cankers, decline. Fertilize lightly next spring if alive.

**Reference:** UMN Extension on Fill Soil Removal