Browing leaves on a pin oak
Our pin oak leaves began to turn brown about a month ago. At this point there are more brown than green leaves with the top having more green leaves. The tree is about 40 feet tall with a trunk circumference of 28 inches. It was transplanted about 8 years ago. The soil is heavily clay. No other nearby pin oaks are displaying similar browning. It is not showing the symptoms of bacterial leaf scorch. What might be the problem?
Our plant pathologist has looked at your photos and diagnosed it as bacterial leaf scorch. The leaf browning patterns and the fact that the tree is browning from the bottom up both point to this disease. Here is our webpage about it: http://extension.umd.edu/hgic/bacterial-leaf-scorch-trees
For a definitive diagnosis, contact a major tree service company such as Bartlett or Davie which can confirm it with a tissue sample lab report.