Jennings Environmental Education Center, Route 528 near the intersection of Routes 8 and 173, Slippery Rock, hosts a one-hour presentation on "Trees and Forests of America" with photographer and writer Tim Palmer at 2 p.m. Sunday. Palmer will present his slide show of forests based on his new book of photography of Pennsylvania, Alaska, Florida and forests in between. Jennings is open from 8 a.m. to 4 p.m. weekdays and on weekends as scheduled. The trails are open daily from sunrise to sunset. Call 724-794-6011 to confirm programs. A spring wildflower walk is planned for 2 p.m. May 9.

<B>A free family fly fishing program</B> hosted by the Pennsylvania Fish and Boat Commission and the Department of Conservation and Natural Resources will be held from 10 a.m. to 2 p.m. Sunday at Oil Creek State Park. Learn basic fly fishing skills such as types of gear, knots and casting. No fishing license is required for participation. All equipment will be provided. But adults must bring a child and children must bring an adult. Participants must be at least age 8. Registration is required. Call 814-676-5915. Visit www.fishandboat.com.<B>Crooked Creek Environmental Learning Center</B>, 142 Kerr Road, Ford City, holds its annual open house from 10 a.m. to 3 p.m. Saturday. Naturalist Dave Beale will lead a nature walk at 10:30 a.m. Reptile and amphibian expert Terry Laux will conduct a program at 1 p.m. Bob Chilko will exhibit some of his hand-painted bird carvings. Hands-on activities, a plant sale and food will be available. Admission is free. Call 724-763-6316 or visit www.crookedcreekelc.org.