Tree doesn't look well

BobH

Hi;
We are just heading in to an early Autumn (Sandhurst, UK), but one of the trees (Beech?) at the bottom of the garden is looking unwell - Can you tell from the picture whether it is just naturally progressing, or should I be concerned?
I'll put a link to large tif files as well as a smaller jpg.

Thanks and Regards
Bob
http://www.hallsworth.eu/small-20110906treenotwell1.jpg
http://www.hallsworth.eu/small-20110906treenotwell2.jpg
http://www.hallsworth.eu/20110906treenotwell1.tif
http://www.hallsworth.eu/20110906treenotwell2.tif