The Kennebec Estuary Land Trust invites the public to join staff member Chris Cabot to learn and practice using GPS 9 a.m. to 2 p.m. Saturday, April 13.

Participants will have an indoor orientation and then venture to Thorne Head Preserve for infield application of GPS devices and skills.

GPS — or Global Positioning System — is a satellite navigation system accessible to the public via GPS devices. It is a popular tool for courseplotting and map making.

At Thorne Head Preserve, participants will use GPS to plot and track springtime vernal pools — seasonal, fish-free pools of water that provide valuable habitat for a variety of plants and wildlife. This type of data has not been collected at the preserve in the past and is significant habitat resource information, KELT officials said.

This event is free and open to public, but the course framework is geared for adult participants. Registration is required, due to the limited class size, by Monday, April 8. Contact Becky Kolak at 442- 8400 or bkolak@kennebecestuary.org to sign-up.

Participants are encouraged to bring their own GPS units; a limited supply of devices will be available for loan. This is a rain-or-shine event.

The workshop is one of several offered in the spring:

— On Saturday, May 11, Chainsaw Training for Women will be led by veteran wood cutter and part time logger John Cullen.

— On Saturday, June 8, Botany & Habitat Management with state ecologist Andrew Cutko will lead property owners to identify “good, bad and interesting plants.”

The Kennebec Estuary Land Trust is a membershipsupported organization dedicated to protecting the land, water and wildlife of the Kennebec Estuary, holds easements on more than 2,000 acres of private land and maintains eight preserves for public enjoyment. For information, visit www.kennebecestuary.org or call 442-8400.