Shamel Ash Sunscald: Black Bark, One‑Sided Dieback

Diagnosis: Sunscald, Not Borers

Black, peeling bark on one side (south/west) of your 8‑yr Shamel ash is classic sunscald—winter freeze‑thaw cycles rupture thawed cambium cells.

Why One Side?

• South/west exposure = intense winter sun.
• Thin‑barked species (ash, maple, linden) are most vulnerable.
• Frost‑damaged neighbor tree may have thicker bark or better shade.

Management

1. Wrap trunk with white tree‑wrap paper each fall until bark roughens (3–5 yrs).
2. Spray Merit (imidacloprid) on damaged bark to deter borers.
3. Fertilize: 1 lb 10‑10‑10 per inch trunk diameter, watered in. Repeat fall.

Do Not

Paint/seal the wound—traps moisture, worsens decay.