Thousands of volunteers are expected to help build trails, plant trees and remove trash on the 14th annual National Public Lands Day scheduled for Sept. 29, 2007.
Last year 100,000 people turned out to join the effort.
This year, organizers are making a special effort to weed out invasive plants that take over habitats and squeeze out native species.
Events are scheduled in parks, nature preserves and other outdoor areas all over the country. To find a site near you, go to www.publiclandsday.org, then "Get Involved'' and "Find a Site,'' where you'll see a clickable map.
National Public Lands Day is a public-private partnership involving many federal, state, and local land agencies, which work with business partners and nonprofit organizations on local events. The National Environmental Education Foundation manages the overall project with Toyota, the Leave No Trace Center for Outdoor Ethics, and the Girl Scouts of America among the sponsors.