Well, let's identify the problem first before we even begin to talk about tree removal.
Step 1: Identify the causal agent, likely a borer of sorts. Take multiple high-resolution digital images and email the images to your local UI Extension office for identification. Yes, this will require some Sherlock Holmes-like investigative work on your part.
Step 1 (alternative): Contact a certified arborist for an on-site assessment. A qualified certified arborists should be able to determine the causal agent.
IL Certified Arborists: http://www.illinoisarborist.org/CertifiedArboristsNew.htm
Step 2 - Maintenance or Removal: Based on the overall health (condition) of your tree: (a) water and fertilize, (b) insecticide treatments, (c) pruning, or (d) removal.
Again, the vast majority of tree health (insect, disease, and environmental stress) questions must be addressed on-site by a forester, certified arborist, or a horticulturist.
