More than 130 volunteers have donated more than 7,400 hours at Lassen Volcanic National Park from October to July.
Volunteers, who were recently acknowledged at an appreciation day, provide a variety of services, educating visitors, helping with field surveys, removing nonnative plants, providing photography and serving as campground hosts.
"Volunteers are truly one of our most valued resources," said Lassen Superintendent Darlene M. Koontz.
Spotlighted in a news release for their service were campground hosts Steve Gibson and Lynne Hadel, and ski patrol participants Phil Finkel and Joe Wolner.
Gibson, a Sacramento resident, was honored as Volunteer of the Year for his customer service and help with maintenance projects.