Come to Spiegel Grove, a level II arboretum and home of the Hayes Presidential Library & Museums, and learn about a variety of tree-related issues, including the effects of bats, climate change and invasive species on trees. The symposium includes a tree tour of Spiegel Grove and lunch. Registration for non-members is $40, and registration for Hayes Presidential Library & Museums members is $35. For the full schedule and to register, visit rbhayes.org. Registration begins at 8 a.m.