Thousand Oaks landscape architect Thomas Kaye will lead a Spring Ecology Trek on Sat., April 29 from 9:30 to 11 a.m. at the Calabasas campus of Soka University of America, 26800 W. Mulholland Hwy.

Admission is free. Rain will cancel the event. Reservations are required and may be made by calling (818) 878-3741.

The trek, which will occur at a leisurely pace, will include a discussion of the geologic history of the area; the significance of the native flora to the Chumash natives; an identification of poison oak from its benign, non-dangerous look-alike plant, the squaw bush; information on poison oak's naturalplant antidote, mugwort; and a review of how animals and plants cope-and sometimes thrive-in the Southland's Mediterranean climate.

Walk participants may also expect to see remnants of an extinct volcano and its ancient lava flow as well as markings of native wildlife and a trapdoor spider den.