I know they're more of a parkland species, but if anyone has horse chestnut trees in their woodand has noticed the leaves turning brown and shrivelling up early in the season, it could be under attack from a ' horse chestnut leaf-miner moth'. More details here and how wasps are leading the fight back by planting their eggs in these minute catapillars.
http://planetearth.nerc.ac.uk/blogs/story.aspx?id=768