Quercus douglasii | Stanford Dish
Despite their beauty as seedlings, trying to grow Blue Oaks on the Dish has been frustrating. Seedlings grow slowly, if at all, and most are consumed by powdery mildew by summer. Acorns are virtually impossible to find on the mature trees for the last 30 years at least - regular mast (acorn production) assessments have been made. During this time, a shift to a slightly cooler, and moister, summer has been noted. Blue Oaks at the Dish are in an "outpost" of Blue Oak range. With climate change, shifts in plant range have been noted throughout the world. A range shift is created by plants dying out, and not reproducing, in an area where they have been historically present. This process is known as extirpation.