Ash

Ash trees produce moderate amounts of allergenic pollen. They are related to olive trees and share significant cross-reactivity. Ash pollen contains the allergen Fra e 1, which is structurally similar to olive pollen's Ole e 1. The emerald ash borer has severely impacted ash populations in recent years.

If you're allergic to ash pollen, you may also react to:

• Olive (strong cross-reactivity — same family Oleaceae)
• Privet (Ligustrum)
• Lilac (Syringa)

• If you're allergic to olive pollen (common in California), you'll likely react to ash as well.
• Ash populations are declining due to the emerald ash borer, which may gradually reduce ash pollen levels.
• Ash pollen overlaps with oak season, so symptoms may be attributed to oak when ash is the actual trigger.