The USDA Forest Service has been providing supportive research for many years on what they call the gathering of "non timber forest products," and their reports share many ways that communities adaptively manage their shared landscapes where people forage.
U.S. Forest Service. 2013. Increasing access to food in urban agroecosystems – food security, foraging, and urban green space managing in an era of changing climates. Washington, DC: U.S. Department of Agriculture, Forest Service, Urban Natural Resources Institute. [webcast]. Available athttp://www.unri.org/webcasts/international/ (Accessed Sept. 4, 2013).
McLain, R.J.; MacFarland, K.; Brody, L.; Hebert, J.; Hurley, P.; Poe, M.; Buttolph, L.P.; Gabriel, N.; Dzuna, M.; Emery, M.R.; Charnley, S. 2012. Gathering in the city: an annotated bibliography and review of the literature about human-plant interactions in urban ecosystems. Gen. Tech. Rep. PNW-GTR-849. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 107 p.
McLain, Rebecca; Poe, Melissa; Hurley, Patrick T.; Lecompte-Mastenbrook, Joyce; Emery, Marla R. 2012. Producing edible landscapes in Seattle's urban forest. Urban Forestry & Urban Greening. 11: 187-194.
People also forage outside what's traditionally understood as "the forest" in cities: The Food Group's Fruits of the City program organizes gleaning of all sorts of urban fruits.
Spurse's "Eat Your Sidewalks" project focuses on often unnoticed foods everywhere.
And the Lake Hiawatha Food Forest project in Minneapolis is gathering communities interested in urban foraging to envision what it would take to restore urban food forests, especially around the wild rice wetlands of Lake Hiawatha.