find. The few oaks that grow in the forest are mixed in with beeches, and only their topmost tips reach the light. In the city, however, oaks stand out in the open, where they are warmed by the sun all day long. The caterpillars love this. And as the whole “forest” in urban areas offers such perfect conditions, it’s no surprise that there are population explosions, which are a stern reminder that oaks and other species growing along the streets and between houses have to fight for their lives.