This picture is of a Beech tree branch in a wood at Todmorden, which has recently split along the centre. This is caused by the loading on the upward growing branch trying to reduce the curvature. In tree terms it is known as a 'Hazard Beam'.
These splits can be good habitats for wildlife but this branch will fail at some stage. On the main trunk there are some curious buckling ridges which show the tree has been under stress for some time.
I don't know whether it is general in the valley but in Todmorden many mature Beech are rapidly loosing vigour and collapsing. It doesn't seem to be necessarily old age that is the problem; I have seen Copper Beech loose all vigour and within a couple of years are dead.