(Question)
I have a copper beech tree which is about 16 years old. It normally holds much of its leaves during winter. However last night many of the leaves fell which has never happened before. Is it because of the unseasonably warm weather or is something wrong with the tree?
(Answer)
Thank you for contacting the Toronto Master Gardeners.
Beech Trees along with certain oak, ironwood and witch hazel exhibit leaf marcescence, where leaves wither and die but don’t fall off. In order for leaves to drop in the autumn, deciduous trees develop a separation layer (called the abscission zone) between leaf stalks and tree branches, so that leaves can break off without harming branches.
It’s not clear why leaf marcescence occurs – one theory holds that this helps prevent leaf buds from drying out over winter. And, as the leaves will eventually fall off and decompose come spring, this process could also be helpful for the tree, by providing nutrients at a useful time.
You don’t mention any problems with your tree. Have you noticed anything unusual with the growth of your tree during the summer? If your tree was healthy during the summer then I would not worry about your tree dropping its leaves. It is more likely the fact that we have had unusually warm weather for the last two weeks. Just in case, be vigilant come spring. Watch for diseases, e.g., the dead tissues at the tips of new shoots can be a breeding ground for fungi.