Posted: 20/01/2014 at 19:39
Oh dear, your apple trees don't seem to have much luck do they?
If this one is healthy and fruits and you want to continue to look after it I can see no alternative but to gently remove the concrete from around it's trunk and replace it with good topsoil and well-rotted farmyard manure. I would want to give it a clear circle of soil of at least 6 ft in diameter, preferably 8ft,.
However has the poor thing been getting any water at its roots?
As far as I'm concerned, if the concrete stays you might as well give up on the tree