I have a male monkey puzzle tree, very mature and seemingly healthy. However just under a year ago I had a new driveway put in. They have left a good space around the base of the tree which now has a porous weed liner and shingle coverage. A couple of the branches are brown (though they have been for a while) up to about half-way high. However the latest very sudden change is that one of the lower (but not lowest and therefore obvious branches to turn brown) has turned yellow and now brown very quickly. The rest of the branches have nice bright green tips and there are male cones from 3/4 of the way up to the top still there (although now brown and dropping off due to the time of year). I am hoping this is just a natural thing and isnt the start of the tree's decline. I absolutely adore the tree and would be truly gutted if it started to die. Someone I know said there is trend at the moment for monkey puzzle trees dying and that no-one knows the cause - maybe an in-species condition. Is this possible? Could it be something I have done when replacing the driveway? Or is it all likely to be ok? Any advice would be greatly appreciated.