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Understanding Burls and Crown Galls on Oak Trees

Benign Tumors and Bacterial Galls: The Baseball-Sized Growths on Oaks

These are burls (irregular grain, prized for woodworking) or crown galls (caused by Agrobacterium tumefaciens bacteria entering wounds). Not two oak species in one tree. Bacteria insert genes causing uncontrolled cell division. Some burls are non-bacterial. Both are generally harmless to tree health.

Trees: Oak Burls: Harmless Oddities Prized by Woodworkers; Oak Decline After Paving: Root Damage and Recovery Plan; Oak Insect Galls: Benign Wasp Nurseries on Mature Tree; Oak Wilt vs. Oak Root Rot: Diagnosis and Long-Term Management; Live Oak & Fill Soil: Why 2-3 Feet of Fill Will Kill Your Tree; Live Oak Pruning: Stop Topping, Prune Low Branches in Winter; Oak Trunk Decay: Management and Structural Support; Diagnosing and Managing Hypoxylon Canker in Oak Trees; Oak Tree Seed Drop and Leaf Shed: Normal Cycles; Identifying Burls and Crown Galls on Oak Trees

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