Graham Tree Service

Google Business Profile | Tuesday, July 7, 2026

Oak Root Rot in the East Bay: How to Recognize It Before the Tree Becomes a Hazard

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Oak trees are among the East Bay's most valued and longest-lived, and they're vulnerable to a fungal threat common in California soils: Armillaria root rot, or oak root fungus. One of the more widespread tree diseases in Alameda and Contra Costa counties, it kills slowly enough that many homeowners don't notice until the structural damage is done.

Early signs include yellowing or undersized leaves in the growing season, thinner canopy than previous years, dead branches appearing faster than expected, and mushroom clusters at the base in fall.

The challenge with Armillaria is that by the time symptoms appear, the root system may already be badly compromised. A tree that looks like it will make it through summer sometimes fails under storm load without warning.

If you have mature oaks on your San Leandro, Oakland, or East Bay property and you've noticed these signs, a professional assessment is worth getting. Graham Tree Service has evaluated and removed hazardous trees here for over 50 years.

#OakRootRot #EastBayTrees #SanLeandroCA #TreeDisease #GrahamTreeService


Image / Media Suggestion

Close-up of a mature oak tree with visible signs of decline, mushroom growth at the base, or an arborist inspecting the root crown of a large oak. Authentic job photos from East Bay properties are strongly preferred.

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Canva text suggestion: "Oak Root Rot Kills Slowly — Until It Doesn't" or "How to Catch a Sick Tree Before It Becomes a Hazard"


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