Gall wasps lay their eggs on the underside of the Oregon white oak leaves. When the egg hatches, larvae produce a substance that induces swelling in plant tissues and forms a gall. It protects the larvae as it matures and provides food.
This tree next to the White Oak Pavilion has an abundance of galls growing on the leaves. They are yellow with red speckles and turn an amber color as they age. They have paper thin shells and glow in the late afternoon sunlight. These beautiful ornaments don’t harm the tree. Chickadees will soon start opening them and eating the larvae inside.
