Dead Apple tree

I have 2 apple trees (over 60 years old ). This year one is going to produce a good crop while the other is completeley dead (no green on it ) the trees are close together and last year the dead one produced some fruit although less than previous years what causes this ? Disease or age?

 

Thanks Marley, as you will see i'm a complete novice so thanks for the infirmation

 

Johnnie, old age (could be over 60?) or disease....could be anything and we can only guess really

Remove it asap

 

Thanks again for all your help. Tree has been cut down and am awaiting better half's instructions