The Rangers partnered with an academic team from the University of Pittsburgh to develop the activities for Saturday's event.
Some 200 volunteers spent the morning planting trees at an area national park
Dozens of volunteers are working at the flight 93 memorial this weekend to plant trees, in an on-going effort to remember those who died on September 11, 2014
Hundreds of thousands of people travel to the site annually.
The Park Service will spend the next several years working to suppress the spread.
Winter schedules for National Parks have also been announced.
The former land owner claims the land is worth much more than he was paid.
The National Park Service awarded a contract for the construction of the new Flight 93 Visitor's Center.
Mother travels from Japan to Pennsylvania to honor her son who died on flight 93.
Organizers say everything that happened at the Flight 93 ceremonies couldn't have happened without a special group of people.
Family members and volunteers light up the Flight 93 Memorial.