Sibley lecture: Friday, April 7, at 8 p.m., in the Unitarian Church. This event is being co-sponsored by the conservation trust and the Warner Free Lecture Society.

Tree-for-all: April 8, from 9 a.m. to 1 p.m., at the Transfer Station.

Tree-for-all: April 9, 11 a.m. to 1 p.m., at the Old Post Office in the Town Center.

Great Elms spruce-up: April 22, 9 a.m. to 3 p.m., at the Great Elms, 105 Stow Rd.

Raindate: April 23, 9 a.m. to 3 p.m.

Walk and talk, a scavenger hunt at Shaker Village and Holy Hill: April 29, 2 p.m., in the parking lot at Ann Lee Field.

Day of stewardship: April 30, 1 to 5 p.m., at the Brehm Land (meet at Great Elms).

Earth Day fair: May 4, 6 to 8 p.m., at Harvard Elementary School.