Good Evening Mariann, 

Thank you for contacting the U of M Extension Service. 

From viewing your photo, it appears the stems and leaves are still on the plant, but it has been defoliated? Or did the leaves turn dead and fall off. I am not sure from the photo. 

Did you inspect the plants/leaves for any pests as they failed? Are there any other symptoms on the plants? 

If you feel the leaves have been eaten but an insect, here is a link about the sumac flea beetle: https://www.inaturalist.org/taxa/215269-Blepharida-rhois

We've had a wet summer up until September and then it's been dry. Have you watered them at all? 

Here is a link about the Tiger Eye Sumac: https://hort.extension.wisc.edu/articles/tiger-eyes-staghorn-sumac-rhus-typhina/

Here is another link about the plant from the MN Horticulture Society: https://northerngardener.org/plant-profile-tiger-eyes-sumac/#:~:text=It's%20important%20to%20maintain%20a,your%20mailbox%2C%20join%20the%20hort!

This information discusses consistent watering and soil type. Neither article discusses pest or disease problems. 

Good Luck!