By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665.

Maples

Have you noticed any maple trees that appear brown or reddish and have fewer leaves than usual? The seeds, not the leaves, make the tan/red color. Those seeds are so plentiful this year that they can easily be spotted from a distance.

Maples with heavy seed crops may appear tan or reddish due to the color of the seeds and having very few green leaves in the canopy. Photo: Wisconsin DNR.

Why does the increase in seed production mean fewer leaves? It takes a lot of energy for a tree to produce either. There often isn’t enough energy left in a high seed crop year to make many leaves. The lack of leaves tends to be focused in the upper crown or sometimes even throughout the entire crown.

When the seeds drop off, those trees will appear thin with very few leaves and will probably look sickly. Sometimes a heavy seed crop can mean the tree is stressed, but other times it just means it’s a good seed year in that area.

This occurrence does not warrant forest management. Just be aware that some maple crowns will look thin throughout summer. If you have a maple in your yard that produces many seeds, you should water your tree during dry periods to help minimize any additional stress.

Oaks

You may have also noticed oaks with reddish-brown leaves that are off-color or much smaller than normal. Some oaks develop late due to the long, cold spring. As summer temperatures continue, the leaves will fully enlarge and turn a more normal green color. No forest or yard tree management is necessary for these oaks. Give them some time – they’ll catch up to summer just like we have.