Question
I have a 20-year-old summit ash (about 18" trunk
diameter) that has not been well for 3 years.  It leafs out
very late, drops early and perhaps 25% has pretty much
died off.  One arborist analyzed it and said 3 years ago it
had a root girdling it and that there was no hope, but it
keeps hanging on.  Before I have it removed, do you have
any opinions?  Also, if I do remove it, along with the stump,
I would very much like to plant a clump aspen on the very
same spot, as I haven't a lot of flexibility with the location
on that part of the yard.  What do you think?  Thank you!

Answer
Bruce,

Your arborist is correct.  A tree with a girdling root should be removed.  A tree in this condition goes through a slow decline that could last many years.  Think about it as being strangled except very slowly.  

I do not have much of a problem planting a tree on the spot where one is removed.  Make sure you grind the stump out completely.  Any roots that are left will decompose fairly quickly.

good luck

Gary