From the sidewalks of inner-city Milwaukee to Alaska's rugged White Mountains, thousands of volunteers will pick up litter, clear trails and repair fences to celebrate National Public Lands Day this Saturday. Last year, nearly 100,000 volunteers across the country came out to help care for the federal, state and local lands that make up more than one-third of the United States' territory. When the program began in 1994, there were 700 participants.

For the Bureau of Land Management the national focus will be to counter the tide of invasive plants and animals that have usurped native species' habitat, according to Martha Malik, a spokeswoman for BLM's Milwaukee field office.

The volunteers also will be working on a range of projects that BLM and other federal agencies do not have the staffing and funds to complete themselves. Officials estimate the volunteers will make an "in-kind" contribution valued at more than $12 million.

Some of the projects they will tackle include repairing the Red Spring boardwalk in Nevada's Red Rock Canyon National Conservation Area, removing debris at California's Carrizo Plain National Monument and refurbishing signs and kiosks in Wyoming's Pryor Mountain Wilderness Study Area.

At Malik's site, the Milwaukee Urban Tree House, volunteers will help weed, plant flowers and mulch a 2.8-acre prairie area in the middle of the city. But another large part of the project involves reaching out to children whom Malik says have had little experience with the outdoors.

"We will provide hands-on field experiences for camping and hiking," Malik said. "Kids will actually put backpacks on their backs. The area is kind of hilly, so they'll go down a hill and up a hill. There will be tents set up; they'll get to go inside a tent and lay down. For some of the youth, they've never been inside a tent, never seen how backpacking and camping equipment look."

The Milwaukee office will have some younger helpers as well -- the local Girl Scout and Boy Scout troops on hand to help with planting. Additionally, the troops will provide sign-up sheets in an effort to get more area children involved with the scouts.

Farther west, in Utah, Girl Scouts will pick up trash scattered along the trails by the Virgin River.

Troop leader Lisa Reid said five troops, or about 30 girls, would be on hand to help with the cleanup. She said the experience will benefit the scouts as well as the river.

"They use the trails quite a bit here in St. George, so I think it will help them realize that littering in the area makes things really worse," she said. "Not only that, it goes into the river, so when they see that I think they will see the effects on the environment and how important it is to us."

To the federal, state and local agencies that own the lands, the volunteers help is invaluable.

"We would not be able to complete [the prairie project] without their help," Malik said.

Linda Price, the BLM's monument manager at the Vermilion Cliffs National Monument in Utah, agreed. BLM is delaying their field project at the monument until cooler weather arrives in November, but hopes to enlist a number of volunteers to build a barrier to keep visitors' cars off unique rock formations on the mountain.

The project "absolutely" would not get done without volunteers, she said. "It would probably be so far down on the priority list, it wouldn't get done for a while. The help we get out of the volunteer program is just essential."

That help is needed, BLM employees said, because public land agencies seem to be perpetually underfunded.

National Trust for Historic Preservation President Richard Moe echoed their feelings. "I think as a rule most public land agencies are underfunded and can always benefit from the assistance of volunteers, particularly in terms of monitoring and helping to look out for the best interests of those lands," he said.

Moe has been a longtime advocate for the United States' public lands and is on the board of directors for a new foundation that launched this week, just prior to the massive volunteer effort for National Public Lands Day.

The National Conservation System Foundation aims to protect and promote the public lands listed under the BLM's National Landscape Conservation System (NLCS). NLCS is made up of lands already under federal management and allows BLM to continue monitoring them at local levels. However, it sets up a mechanism to guide and direct the entire system. Former Interior Secretary Bruce Babbitt set up the 26 million acre structure in 2000, and is also on the foundation's board of directors.

Currently, the NLCS exists through administrative designation, and some fear it could be jettisoned when a new administration gains control of the White House. To avoid that situation, both the House and the Senate are reviewing bills that would give the NLCS congressional recognition.

"The legislation would simply codify what already exists," Moe said. "It doesn't create any new units or protections; it simply gives added recognition to 10 percent of BLM land that is very significant."

Moe said he is optimistic that H.R. 2016, the "National Landscape Protection Act of 2007," and its Senate companion bill S. 1139 will pass. The House National Parks, Forests and Public Lands Subcommission Chairman Raul Grijalva (D-Ariz.) and Senate Energy and Natural Resources Chairman Jeff Bingaman (D-N.M.) sponsored the respective bills.

"I think [the legislation] is moving along pretty smoothly," Moe said. "It has bipartisan support. A few questions inevitably arise, but I don't see any serious problems at this point. We're very pleased it has bipartisan support and very pleased the administration supports it."

Former Interior Secretary and foundation board member Bruce Babbitt also praised the administration's backing of the legislation. "The Bush administration I think deserves credit for working and managing this system," Babbitt said. "I think they've done on the whole quite a good job." Babbitt said the Bush administration's support "reflects a desire within the BLM and the administration frankly to say we've recognized [that] BLM, in its multiple use mandate, should have a clearly defined conservation mission as a part of it. I think the trend is very positive."

Babbitt said he also believes public opinion on the establishment of various monuments in the NLCS system has shifted since former President Clinton's controversial executive orders in 1996 and 2000 created them. "There's a historic kind of progression around the establishment of national parks and monuments," he said. "Whatever initial divisions there may have been leading up to the creation of the affected areas, almost uniformly you see a transition towards broader and deeper local support [as] the benefits and the future become more obvious to people in the community."

However, Babbitt acknowledged that in order to be run properly, NLCS will need more resources, which is where the foundation can help.

"The effort to pass that legislation is in very good hands," said Ed Norton, Chairman of the Foundation's Board of Directors. "Our focus is much ... longer term." Norton said the foundation would look at building capacity and supporting local organizations in an effort to promote and preserve NLCS.

Rep. Mary Bono is another strong supporter of NLCS and of the foundation, which is hoping to garner funds from private individuals and organizations.

"I applaud the formation of the [NLCS] as an important partner in our effort to permanently protect the unique lands that millions of Americans treasure," Bono said in a statement.

"The foundation is being launched with folks who have been visionaries with managing public lands for quite a long time," said Elyssa Rosen, communications director for the Conservation System Alliance. Members of its board of directors include former governors, BLM state directors, Interior secretaries and environmental activists.

"The conservation permanence bill has been moving since spring," Rosen said. "There's a lot of activity happening on public lands overall" like the National Public Lands Day.

"We like the fact that the effort for permanence is coinciding with that," Rosen added.

Senior reporter Dan Berman contributed to this article.