Planting trees would not only beautify the city, Kemba determined, but also provide work and volunteer opportunities for the young men of Oakland. She was right. To see what Kemba, and her Urban Releaf organization, have accomplished, watch Garvin Thomas' report above.

Three years ago when Donna Love started working to build nature playgrounds at Hurlburt Field, she had no idea the impact her efforts would have. She'd heard research about how being outdoors in a natural setting reduces stress for children and helps them develop mentally and emotionally.

Americans have a history of persevering through tough economic times to leave legacies of stewardship. Construction of New York City's Central Park progressed through the Civil War, and during the Great Depression, networks of public parks and forests were expanded. Lives and lands were healed, and countless trees were planted whose shade we continue to enjoy.