Environment : Notes about your surroundings.

Plants--Southern California Botanists will hold a symposium on endangered plant communities of Southern California from 8:45 a.m. to 4 p.m. Oct. 28 at Cal State Fullerton. Admission is $7. For information, call (714) 773-2428.

Meanwhile, Bill Neill of Anaheim is leading another desert trip to clear out non-native tamarisk trees--this time a two-day trip beginning Saturday to Ash Meadows and Shoshone. For information, call Neill, (714) 779-2099.

Teachers--Two events this week are geared to local teachers. The California Environmental Education Awareness Program offers a teacher workshop in environmental education Wednesday from 8:45 a.m. to 3:15 p.m. at the Orange County Department of Education. There is a $5 fee. Call (209) 488-3337 for information.

Also, the Santa Ana Zoo offers its Fall Teacher Reception on Thursday from 3:30 to 5:30 p.m. with refreshments, tours and education displays. Reservations are required. Call (714) 836-4000 for information.

Events--A program on shore birds is offered at 9 a.m. Saturday by the state Fish and Game Department at the Upper Newport Bay Ecological Reserve. The program meets at Eastbluff and Back Bay drives in Newport Beach. For details, call (714) 640-6746.

Members of the Crystal Cove Interpretive Assn. will lead a canyon walk Saturday from 10 a.m. to noon, starting at park headquarters in El Moro Canyon, on the inland side of Coast Highway north of Laguna Beach.

Oak Canyon Nature Center in Anaheim Hills offers an 8 a.m. bird walk Saturday, followed by a 10 a.m. program. For information, call (714) 998-8380.