In Sacramento, they pick figs, kumquats, and plums from public trees. In New York, they harvest purslane–an edible flower–from the cracks in the sidewalk. Down south, it’s fiddlehead ferns, and just about everywhere, people are picking black walnuts, wild mushrooms, and dandelion greens.

Urban foraging–gathering fruit, vegetables, and other useful things from parks, lawns, and sidewalks–isn’t a new thing. But as more urbanites become aware of the free bounty surrounding them, new issues are–pardon the pun–cropping up. When a public park’s berry patch is raided, whose responsibility is it to make sure there are some left for everyone to enjoy? What about pesticides?

The Institute for Culture and Ecology has been studying urban foragers since 2008 to understand how foraging fits into a city’s ecosystem. The latest project, studying foragers in Seattle, kicked off in early 2010 with partial funding from the American Recovery and Reinvestment Act. Since then, researcher Melissa Poe and her team have interviewed 35 foragers.

Read the rest at Nat Geo Green Guide to learn about Poe’s findings.