top died on dunstan chestnut

[jpe40]

I have 3 7-8yr old Dunstan chestnuts planted in a row. I noticed that on one of them the top 15 ft is dead and the next set of branches down has much smaller leaves. the rest of the tree and the other 2 seem fine. should I let it go or cut the top dead section off. thanks in advance
jpe

 

[Telemark]

Cut out the dead wood. But make sure it is dead before you cut it out.