Heavy seed production by a red maple. The Ohio State University.

By Todd Lanigan, forest health specialist, Eau Claire. todd.lanigan@wisconsin.gov, 715-210-0150 and Paul Cigan, forest health specialist, Hayword. Paul.Cigan@wisconsin.gov, 715-416-4920

There have been reports that some elm and maple trees in the state have fewer leaves than normal this spring. The likely reason is that several elms and maples produced an unusually large amount of seed this year, which trees do periodically. During a heavy seed production years, the tree will produce fewer leaves, which may make it appear sparse.

Although trees normally engage in heavy seed production from time to time, such activity can also be initiated by environmental stressors such as drought or the presence of extreme moisture. The reason for this spring’s heavy seed production is anyone’s guess. It is difficult to determine the exact cause – this may be a normal heavy seed production year or an environmental stressor that we are not aware of may have started the cycle. In either case, forest managers should make note of heavy seed production years in their records in case the information becomes relevant in the future.