The event began in 1994 with about 700 volunteers; this year, organizers expect about 110,000 participants.
"It's growing every year," Rakauskas said. "We think governors in 37 to 40 states will be proclaiming National Public Lands Day as a state event."
Those "public lands" can be schools, parks, municipal, county, state or federal, he said. Registering a site for a project is easy - it can be done online at the official Web site, which is www.public landsday.org.
Projects can include anything from picking up trash to planting trees. This year, Rakauskas said, the focus is on controlling invasive species of plants that are causing problems on public lands.
And that's just fine with the folks at Catoctin Mountain Park in Thurmont, Md., where volunteers are being enlisted to do battle with Japanese stilt grass.
The plant has been cropping up in various parts of the park, choking back native plants and attempting to overtake trails. Native to India and other parts of Asia, the plant can grow up to 3 feet tall. "We have tried several things to help control it," Ranger Don Stanley said.
Two areas particularly affected are the Misty Mount camping area and the Chestnut picnic grounds, according to biologist Becky Loncosky.
Volunteers are asked to meet at the visitors' center at 9 a.m. Saturday to help pull the plants from the ground. "After learning how to identify the target plants, volunteers will seek them out and rip them from the soil. The project requires more enthusiasm than skill," the NPLD Web site says.
Gloves will be provided to those who want them, but Loncosky said gloves aren't necessary. "We can take as many volunteers as possible," she said.
Participants in any of the NPLD events may register at the Web site - or just show up. "No one will be turned away at the door," Rakauskas said.