9 a.m. to 12:30 p.m., Dec. 5 and Dec. 8. Ridgefield National Wildlife Refuge, Carty Unit, 28908 N. Main Ave., Ridgefield. Volunteer work day. Plant and cage native trees in critical riparian areas. Wear waterproof footwear and gloves. Rain or shine. Refreshments provided. Volunteers must sign agreement: www.fws.gov/ridgefieldrefuges/ridgefield/getinvolved.html. * 360-887-3883, email@example.com.