Q.Horse Chestnut Tree Signs of Sickness
Hello –
I have a 60 year old horse chestnut tree that has been healthy and robust for a long time. Last Fall we had professional tree service company come and prune back a lot of healthy branches as they were leaning on the roof of the house. Now, this Summer, the tree has gone from green to brown in August (ahead of cooler temps in Chicago), and has dropped major branches in the last rain storm. The wood is dry and brittle. What can I do to save this wonderful tree? Is it sick?
Thank you!

It's possible that these problems are caused by environmental stresses, such as extreme temperatures:
The brown leaves could also be caused by a fungal disease called Horsechestnut Leaf Blotch:
http://hyg.ipm.illinois.edu/pastpest/200110g.html
https://extension.umaine.edu/ipm/ipddl/publications/5094e/
http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/fungal-spots/guignardia-blotch.aspx
It seems this disease wouldn't be fatal to the tree by itself, but could weaken it and make it more susceptible to damage from other causes. You may want to consult an arborist or university extension agent in your area.