Hi,
We have a well established tree in our garden (maybe 10+ metres tall)
which we think we've identified as a "common beech" (used a book :-).

The last few years since we moved in the tree has been fantastic
however this year, a few weeks after the first leaves came out, they
started to go brown! It looks like almost all the leaves are half
green, half brown. The brown areas are are mostly between the leaf
veins, are crisp and have crumbled away.

Does anyone know what the problem may be?

Thanks in advance for any help!