Question: What is this growth on my Live Oak
tree? It is about 6 feet
up the from the ground on the main trunk which is about 16 inches
diameter at that spot.
Answer: This is believed to be Crown Gall caused
by the bacterium
Agrobacterium tumefaciens. While Crown Gall is normally found
just below the soil line, aerial galls such as this can develop.
normally are of no harm to the tree.