Chinese Pistache 'Keith Davey': Healing Trunk Wound and Long-Term Stability

Chinese Pistache Trunk

Chinese Pistache

The owner previously reported black discoloration at the base of a 'Keith Davey' Chinese pistache. New photos show a healed-over area near the soil line that looked worse last spring. The question: what caused it, and is any treatment needed?

Diagnosis

The healing tissue visible in the photos indicates an old injury—most likely mechanical in origin (e.g., lawn equipment, animal damage, or a previous split) rather than a disease or insect. The tree has successfully compartmentalized the wound, sealing it off with new bark layers.

Long-Term Implications

While the wound is closed, the underlying dead heartwood remains. This creates a structural weak point where the trunk may be more prone to breakage under heavy wind, snow, or ice loads. The tree’s overall vigor is good, so no immediate intervention is required, but the owner should monitor the area and avoid additional mechanical injury.

Care Recommendations

• Maintain optimal watering and fertilization to keep the tree vigorous.
• Keep mulch pulled back from the trunk to prevent moisture buildup.
• Prune only as needed for structure; avoid heavy cuts near the old wound.