I'm trying to determine whether my Holly tree is dying. As you can see in the pictures the leaves are dropping, but are still green. About a year ago the tree suffered some stress due to a major winter storm, but the tree has been fine since then. The tree is close to 20 years old. I will remove the tree if it has a disease. We would of course like to save it if possible. Any guidance or suggestions would be much appreciated. Thank you.