Sounds like tent worms. Last year in Northern Mich we had them every where. What this is, is the cocoon and if you look closlely you can see the caterpillars inside. They start to mature (look like worms) and eat their wayout of the cocoon. It seems they will eat any leaf they find. They stripped one of my ornamental trees last year. Some say to light the cocoons on fire others say spray them with insecticide, or just wait in a few weeks they will be gone and the leaves will grow back.