SMART CYCLING, DEC. 16

Santa Rosa: Sonoma County Bicycle Coalition’s overview of cycling classroom instruction 9 a.m. to 11:30 a.m. at the coalition’s office, 750 Mendocino Ave. A bike is not required but bring a helmet for instructions on proper fitting. $20, $10 for coalition members. The coalition’s Biker Chicks December ride is at 10 a.m. Visit bikesonoma.org or call 707-545-0153.

SATURDAY HIKE, DEC. 16

Glen Ellen: Guided weekly hike at Jack London State Historic Park. Meet at 10 a.m. in the Ranch parking lot, 2400 London Ranch Road. Free admission. Bring water, lunch or snack. Rain cancels the event. Visit jacklondonpark.com or call 707-938-5216.

LAST RUN, DEC. 16

Santa Rosa: The Empire Runners Club holds its last 10K and 2-mile foot race at Howarth Park, Spring Lake Regional Park and Trione-Annadel State Park at 9 a.m. $10 nonmember registration is due by Dec. 13. Same day registration is $20. Register at events@empirerunners.org.

CHRISTMAS TREE HARVEST, DEC. 16

Healdsburg: Help fire reduction work by removing Douglas fir trees where thinning is necessary between 10 a.m. and 1 p.m. in the Riddell Preserve, 550 Westside Road, and receive a free unmanicured Douglas fir Christmas tree. Harvest as many trees as you like. Participants will hike nearly a mile up a steep but well-graded trail to the harvest site and LandPaths will transport the tree you select to your vehicle. Bring snacks and water and wear sturdy boots or shoes. Saws and gloves provided. Hot Chocolate, cider and Christmas goodies available. Register at landpaths.org.

MUSHROOM OUTING, DEC. 16

Guerneville: Join George Riner with Stewards of the Coast and Redwoods for a walk around oak trees at higher elevations and learn about mushrooms in Austin Creek State Recreation Area, 10 a.m. $16 for members, $20 nonmembers. The hike will end around noon and be followed by a question and answer session. Meet at the Volunteer Center/Steward’s Office, 17000 Armstrong Woods Road. Visit stewardscr.org to sign up and get details or call 707-969-2015.

MUSHROOM FORAY, DEC. 17

Santa Rosa: Explore and learn about mushrooms in and around the Laguna de Santa Rosa with retired science teacher Darvin DeShazer an the Laguna de Santa Rosa Environmental Center, 900 Sanford Road. Rain or shine, 9:30 a.m. to 3:30 p.m. For ages 12 and older, children must be accompanied by an adult. $95, preregistration required. Visit lagunafoundation.org to register.

HOLIDAY RUNS, DEC. 16-30

Healdsburg: The Healdsburg Running Company’s year-end 8 a.m. runs include Spring Lake in Santa Rosa on Dec. 16, Jingle Bell Run in Cloverdale on Dec. 23 and Last Run of the Year at Lake Sonoma. The Jingle Bell Pub Run from the HRC at 333 Center St. is 6 p.m. Dec. 26. Call 707-395-0372 or visit healdsburgrunningcompany.com.

SATURDAY HIKE, DEC. 23

Glen Ellen: Join Deborah Large at 10 a.m. for a Saturday hike at Jack London State Historic State Park. Meet in the Ranch parking lot. Free admission. The length and difficulty depends on the participants. Visit jacklondonpark.com.