The volunteers keeping Hoyt Arboretum pristine

• Volunteer arborists, representing dozens of local companies, donate their morning to climbing trees, pruning, removing deadwood and creating wildlife snags across the Arboretum's 189 acres and its 2,300-plus species.
• In the last five years, arborists have contributed more than 1,700 hours of skilled volunteer labor, according to Hoyt Arboretum Friends, which partners with Portland Parks & Recreation for the annual day of service.

What they're saying: "In one day, they provide months' worth of services that would otherwise be out of reach for the Arboretum," Martin Nicholson, the arboretum's curator, said.

If you go: Arborists in the Arboretum will take place Saturday from 8am to noon.

• The 12 miles of trails will remain open during the event, but hikers are encouraged to stop by the visitor's center for information about navigating around work sites.