Changing colors already?

Earlier this week we had received a photo from one of our weather watchers in Oregon, Mary Montana, of a maple tree and the colors were already starting to change.  She had wondered what might cause something like that so early in the season.  Chief Meteorologist Ty Shesky talked a little about it in an earlier blog post.

Another one of our faithful weather watchers, Dom Castaldo, also provided a picture of a maple tree with changing colors and actually provided a little more information as to what might be the cause behind it:

Several conditions can explain early leaf loss. Maples have shallow roots and compete with grass and shrubs for water. The hot, dry spell in July may have drought-stressed the tree. However, if drought was the cause, I think more trees would be affected. In the photo I attached, the tree next to the changing tree is fine. Leaves lose a lot of water – transpiration. So, when water is in short supply, the tree cuts off the water flow to the leaves. The leaves die and fall from the tree. This process is called “abscission.”

Another more plausible explanation is that the wet spring caused fungus to infect the tree. Two fungi species infect Norway maples and cause Verticillium wilt during wet springs. The leaves will turn color and fall in mid-August. As with human diseases, some trees are susceptible to the infection, while others are resistant. We had a wet spring this year.  Also, aphids and sap-sucking beetles can cause maple trees to loose their leaves. These insects burrow into the bark. The tree in my photo has a lot of insect damage. Note the dead branches. For several years, this tree has lost its leaves early.