This is what happens if you are a tree and caterpillars get hungry!
I am not sure but Google lens tells me this tree (from another picture with leaves and flowers) is a Prunus padus (Bird Cherry) and is infested with Bird Cherry Ermine moth caterpillars. The internet assures me that although the caterpillars look to do a lot of damage the trees are resilient and typically recover quite quickly. I hope so because virtually every tree in the area had the caterpillar nests on them.
