Ainsworth Linear Arboretum
Planted by Friends of Trees back in 2003, the Ainsworth Linear Arboretum is home to some 60 varieties of rare and native trees such as ginkgo bilboas, Purple European beechs, and Japanese evergreen oaks—and now’s the time to catch in them all of their autumnal glory. On Saturday meet up with Arboretum curator Jim Gersbach for a stroll beneath this unique urban forest canopy. Discuss the area’s botanic history, learn tree identification techniques, or just marvel at the kaleidoscope of colors.

Ski Swap
Ready to trade up for some new ski gear? Drop by West Linn High School for the 3rd annual Mound Hood Snow Sports Swap. Here’s how it works: for each piece of gear that you’d like to sell, slap down a buck, and if someone buys your goods, the Mount Hood Ski Patrol—the country’s oldest organized ski patrol and all-around good human beings—gets to keep 20 percent of proceeds. The rest? Cold hard cash in your hands. Anyone’s invited to come and browse the deep selection of gear, but one thing that’s not welcome at the swap: those janky circa-1971 Rossignols in your basement.

Birdfest at Ridgefield
Call it an avian-themed Pickathon: On Saturday and Sunday, Friends of Ridgefield National Wildlife Refuge is hosting the 10th annual Birdfest and Bluegrass Festival. The sprawling event takes place at the Refuge’s Carty and River S units, and in downtown Ridgefield. Set off on guided bird and plant walks, take a canoe or kayak tour, chow down at a traditional salmon bake, join in on the “Big Sit” to tally bird species, or sit back with the kids for storytelling, culture demonstrations—and plenty of bluegrass picking.