Tributes to the Planet

To commemorate the 25th anniversary of Earth Day today, several events have been planned for this weekend. Among the offerings:

* Los Angeles Mayor Richard Riordan will lead a free community bike tour beginning at Hansen Dam Sports Center, 11700 Foothill Blvd., Lake View Terrace. Registration is at 8 a.m. today, with the ride scheduled from 9 to 11:30 a.m. Information: (213) 847-3634.

* The 10K Earthwalk will begin on the back lot of Universal Studios with registration at 8 a.m. today. The walk begins at 10 a.m. Participants will walk through the Burbank area, with rest stops at Warner Bros., NBC and Walt Disney Studios. Information: (818) 763-2784.

* An Earth Day celebration will be held from 10 a.m. to noon today at the Agoura Meadows Shopping Center, Kanan Road and Thousand Oaks Boulevard, Agoura Hills. Information: (818) 597-7300.

* Environmental businesses will exhibit their projects from 10 a.m. to 3 p.m. today at the city of Glendale Recycling Center, 800 Flower St. A composting presentation will be given at 10:30 a.m. Information: (818) 543-0644.

* TreePeople will hold an Earth Day celebration from 10 a.m. to 4 p.m. today at Coldwater Canyon Park, 12601 Mulholland Drive. Parking will be available at Harvard Westlake School, 3700 Coldwater Canyon Blvd., with free shuttles to the park. Admission is free. Information: (818) 753-4600.

* The city of Calabasas will have a celebration called “Living With Nature--Earth Day ‘95” from 10 a.m. to 4 p.m. Sunday at the corner of Old Topanga Canyon Road and Mulholland Highway. Highlights will include environmental displays, live music and entertainment, a children’s storyteller, family nature hikes and a recycling collection center. Information: (818) 878-4225.

* The Sierra Club will host a 4-to-6 mile Earth Day Hike and picnic at Topanga State Park today. Meet at the Kiosk in the inside parking lot at the Presbyterian Conference Center at Sunset Boulevard and Temescal Canyon at 9:30 a.m. Call (310) 479-5717.

* The Arroyo Seco Earth Festival will be from 10 a.m. to 5 p.m. today in Pasadena’s Brookside Park south of the Rose Bowl. Call (818) 792-2442.