​Many trees and plants in Indiana suffer from iron deficiency, chlorsis, induced by high (alkaline) soil pH. A symptom from the iron deficiency is the leaf yellowing. Plants suffering from iron chlorosis will often exhibit dieback and poor growth. Chlorosis is especially a problem with trees planted along streets and around homes where the original topsoil was removed or mixed with subsoil. The lime content of many of these subsoils is high. Most likely, the best course of action would be to conduct a soil test for mineral deficiencies and perhaps tissue analysis.

Resources
Iron Chlorosis of Trees and Shrubs, The Education Store
Collecting Soil Samples for Testing, The Education Store
Soil and Water Conservation Districts, Indiana State Department of Agriculture
Certified Soil Testing Laboratories, Purdue Department of Agronomy/Extension
Certified Arborists, International Society of Arboriculture (ISA)

Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources, Purdue University