Did your pin oak's leaves look like this? You probably have an iron deficiancy in your soil. Most pin oak (red oak) trees in the metro area do not get enough iron and have chlorosis. You can identify a tree with the disease by yellowish/light green leaves that may have some spots on them. It is a simple problem but if untreated can lead to an unhealthy tree or a dead tree. Contact us about an easy iron injection to get your tree healthy again.