Live Oak Cavity: Don't Fill, Don't Cover, Just Monitor

A 30-year-old cavity in a 5-ft diameter live oak limb with a 4-ft vertical bark crack below indicates internal decay. Research shows:

• Cavity filling (cement/foam) damages trees—rigid fill rubs, holds moisture, accelerates decay.
• Drain pipes breach the tree's natural compartmentalization barrier.
• Best practice: leave open, improve tree health.

Do This Instead

• Spray area with Merit to deter borers.
• Fertilize annually (10-10-10 at 1 lb/inch trunk diameter).
• Optionally, fill hollow with potting soil and plant flowers—purely aesthetic.

The tree walls off decay internally. Structural failure takes decades; monitor for large limb hollowing.