Industry News: Tree Health

Q: Why is our elm tree dropping lots of leaves early?

Wednesday, August 24, 2016  

Q: We have a healthy 7-year-old elm tree that looks stressed and is losing a good amount of yellowing leaves. The temperature here in Chattanooga has been in the 90s. We have surface-watered and deep-watered--is there anything else we can do to save the tree?

A: Yellowing and early leaf drop of elm can be caused by any number of things. The first thing that comes to mind is Dutch elm disease (DED). This disease is vectored by elm bark beetles, and causes blockage and staining of the xylem tissue. This disease has caused extensive damage to American Elm throughout the mid-west and can be devastating on many species of elm in Chattanooga. Look for stunted growth, especially of the leaves, and look for seasonal changes in the leaves that differ from other local trees of the same species. If you suspect DED, contact a local arborist and have the tree tested for this disease--it can be easily treated with injected chemotherapeutants. Yellowing and early leaf abscission may also be a natural phenomenon that occurs in the southeast during years with high precipitation and high temperatures. It seems that some species of trees are only capable of growing to a certain extent each year and then an excess of carbohydrate production causes the tree to begin the process of dormancy as early as late summer. I have seen this each fall the past few years on the cherry and birch trees in my backyard. They are well watered from a natural spring and they otherwise seem healthy and uber vigorous. Hope this helps.

Responder: Marty Shaw, RCA #470, Franklin, TN