LIMA — The Tri-Moraine Audubon Society will host a field trip, Oct. 17, beginning at 9 a.m. in Gross Memorial Woods, 19201-19887 Botkins Road, Jackson Center, and including two other state nature preserves.

Although only 49 acres in size, Gross Woods is one of the least disturbed, old-growth woods in west central Ohio and one of the few mixed-species swamp forests remaining in this part of the state. There are some big oaks trees: one white oak is 113 feet high with a circumference of 14 feet. The rare pumpkin ash is also there. There is a small parking area and a boardwalk and trail system through the woods.

The next stop will be Siegenthaler-Kaestner Esker near West Liberty. This 37-acre preserve was formed when the last glacier was melting and the meltwater streams were flowing south. The esker was formed in a tunnel carved through the lowest level of the glacier by meltwater streams. Other glacier-related features are kames, a kettle, outwash channel and a ridge.

The third stop will be McCracken Fen near Bellefontaine. The landscape of this preserve was also created by a glacier and is situated in a moraine which contains a kettle with unbroken deposits of peat covered by shrub fen. At least 17 rare plant species have been documented there, including Smith’s bulrush, swamp birch and green spikerush. McCracken Fen is also home to a population of the state-endangered lilypad forktail damselfly.

The field trip is free. Participants should meet in the parking lot at Gross Memorial Woods.

For information, call 419-230-6680.