ARLINGTON, Va. (AFPS, July 9, 2012) -- More than 400 volunteers from children to adults descended on the grounds of Arlington National Cemetery today for the 16th annual Renewal and Remembrance, to honor the nation's veterans and fallen service members by sprucing up the landmark's grounds.Members of PLANET, the nonprofit Professional Landcare Network, brought out 82 professional lawn care and landscape companies from around the country for this year's Renewal and Remembrance. They lent their hands and donated materials and equipment to mulch, prune, aerate, irrigate, plant, spread lime, and cable some of the trees for lightning protection on 150 of the cemetery's more than 560 acres.Since the annual Renewal and Remembrance landscaping event began, more than $2 million has been contributed to the care of the national cemetery, according to a PLANET news release.The cemetery's 8,400 trees are maintained on a four-year pruning cycle. Some are more than 200 years old, cemetery officials said.John Gibson of Swingle Lawn, Tree and Landscape Care traveled from Denver with his daughters Taylor, 17, and Marissa, 15, to join a six-person crew that spread 400 bags of lime to balance the soil's nutritional levels. This is his twelfth year of working with Renewal and Remembrance at the cemetery, and his daughters' first, he said."The very first year," John Gibson said, "I realized what an impact it would make on those people who made an impact for us. It's pretty emotional every year to have a chance to give back. All we do is lawn and tree care, and these guys [sacrificed their lives] for us.""It's nice to give back to the people who gave everything," Taylor Gibson said, adding that she and her sister would come back next year.About 25 of the volunteers' children, ranging in age from 3 to 12, pitched in on the beautification project. But before they planted milkweed, they received a lesson in the importance of how the plants attract the caterpillars of the endangered and migratory Monarch butterfly, and how the caterpillars feed only on that particular plant.Former Navy officer Roger Phelps, promotional communications manager for Stihl equipment, has worked with the children at Arlington's Renewal and Remembrance for 10 years."It's my passion," Phelps said of his work with the project. "These kids are our future, and creating this experience is important."And volunteers bringing their children, he added, is especially meaningful."It's so important, because we live in sort of a virtual world," he said. "These kids are different. They live in a real world. They get their hands dirty, they put the plants in the ground [and] see the roots in the dirt."Phelps said many of the children return from year to year and see the fruits of their labor as the vegetation they planted grows and matures."We take the kids around to all the different areas they've worked on over the years, so they can point to the things they've worked on and planted," he said. "The opportunity for us is to give them an understanding of what it means to serve, and what service means. What they learn here is by working with the plants, they have an opportunity to serve the families and visitors by creating an environment that is pleasant and respectful."The significance of the children volunteering goes beyond planting foliage, Phelps said."We live in a generation that's getting a little separated from what it means to serve in the military," he said. "So these kids learn that at the same time."Phelps related the story of a young girl who once asked her father if all the headstones were people."He had the opportunity to explain to her what this place means," he said.Phelps, a former Navy lieutenant commander, said Arlington National Cemetery is a special place to him."I've got some shipmates and friends in here," he said, adding that many of the landscape volunteers also know someone who is buried at the national cemetery. "It's a personal thing, too."