My thirty foot holly tree is dropping branches and leaves. For two years, my holly tree has been dropping the end of branches that look healthy and have berries on them. At least half of the tree is bare.
Holly Tree Dropping Branches and Leaves
Certified GKH Gardening Expert
This sounds very much like leaf scorch.
Inspect the plant more carefully to rule out insects or signs of disease.
The links below will help you with symptoms and what to look for.