My tree's leaves are turning brown halfway up the tree. The top is all new leaves and the smaller branches are dead.
Silver Dollar Eucalyptus
Certified GKH Gardening Expert
There are several things that could cause this in your tree. If you have had colder than usual winters for the past 2 years, as much of the country has, the stress from the cold may have hurt it. The tree may also have a pest or a fungus. I would recommend treating the remaining tree with neem oil. It will kill both pests and fungus on the tree. You may also want a local tree expert to come out and look at the tree to more accurately diagnosis the problem.