Carpenter Ants and Woodpecker Damage on Pine: Don’t Seal the Cavity

Big Pine with Ants and Woodpeckers: Science Says Leave It Open

You have a 60+ ft pine with carpenter ant/woodpecker damage 6 ft up, 2.5 ft wide. You planned to clean out rot, disinfect with petroleum oil, coat with heated asphalt and cement. Stop.

Why That’s Harmful

• Carpenter ants nest in already decayed wood—they don’t cause the rot. Something else (fungus, injury, disease) started the decay.
• Sealing cavities traps moisture, accelerates rot, and prevents natural compartmentalization.
• Cement doesn’t flex with the tree; water enters cracks and can’t dry.
• Asphalt/petroleum products can be phytotoxic (kill living tissue).
• ANSI A300 standards and decades of research advise against wound fillers.

Better Approach

• Wrap mesh over the opening to deter woodpeckers (no harm).
• Keep area dry; redirect irrigation.
• Accept that decay may continue; the tree may last years or fail—no treatment restores strength.
• If structural risk is high, removal is the only sure fix.

Don’t waste money on “tree surgery” that hurts more than helps.