These are galls, which the tree grows in reaction to an irritant such as wasp larvae. The gall, in turn, nourishes the larvae. This is probably Callirhytis furva. The presence of these galls usually isn’t enough to harm the tree, unless the tree is already distressed and vulnerable to a heavy infestation.
These are galls, which the tree grows in reaction to an irritant such as wasp larvae. The gall, in turn, nourishes the larvae. This is probably Callirhytis furva. The presence of these galls usually isn’t enough to harm the tree, unless the tree is already distressed and vulnerable to a heavy infestation.