The leaf miner has been with us in Bournemouth for a couple of years now. While it doesn't actually kill the tree it turns them brown prematurely and leaves unsightly gaps in the lush green of high summer leafage. Here are a couple of pictures of trees in the West Cliff area. Soon the trees will be brown and bare.
We also need to look out for bleeding canker on Horse Chestnuts. This is more serious and will kill trees. it is spreading fast. So enjoy the Chestnuts while you can. It may be the last time you see them in leaf.