Urban agriculture is a hot topic in sustainability, food, and planning circles. From roof and deck gardens to community gardens to urban farms, urban agriculture has captured the imaginations of activists of many stripes as well as gardeners and eaters. When I mention that my academic work focuses on food access in urban areas, the most common response I get is "oh, you mean like urban ag?" As this interest in urban agriculture grows, some are asking whether food sovereignty – the ability for a population to produce enough food to feed itself – is a feasible goal for American cities.
Those who know far more about urban agriculture than do I don't think that it is realistic for most American cities to produce sufficient food to feed themselves. The reasons are several, but the major one is perhaps the most obvious: Crops are land-intensive, and all but the most depopulated cities lack sufficient vacant land to devote to food production. A quick survey indicates that about one acre per person is required to produce the average American diet. Chicago has a population of about 2.7 million people, and a total area of about 150,000 acres, of which an estimated 20,000 acres are vacant land. In short, it would take 18 Chicagos worth of land to feed the city.
Some who are interested in this topic have started to ask a different question: If our city cannot provide for itself all of the food we consume, are there any particular crops for which we could meet our own demands? Fruit trees, which offer greater produce yields per acre than do row crops, may work well in some cities, especially since they can be incorporated into streetscapes as well as private yards. In San Francisco, the answer may be: Lemons.
Just One Tree (http://justonetree.org) calculates that San Franciscans consume three pounds of lemons per capita. A mature lemon tree produces 200-300 pounds of lemons per year; 12,000 trees could supply all of San Francisco's lemons. Lemons, especially the sweet, thin-skinned Meyer lemon, are easy to grow in San Francisco; the Department of Public Works estimates that the city's backyards are already home to 3,000-4,000 Meyer trees.
The prospect of lemon sovereignty is appealing. The trees are attractive, fragrant, and easy to grow. The dwarf variety can even be grown indoors in pots. They are self-pollinating. And because San Francisco, like most American cities, chose male streetscape trees to reduce the mess of dropping fruit, replacing aged street trees with Meyer lemons will offer not only fruit but a reduction in airborne pollens, thus reducing allergens. Once other cities stop snickering at yet another crazy California idea, they might even follow suit.
There are others who are working to improve access to and democratization of tree fruits in San Francisco. Neighborhood Fruit offers a phone app with the crowd-sourced locations of fruit trees around the city. People are encouraged to harvest fruit from public trees; owners of trees on private land can use the app to giving unwanted fruit to others. San Francisco also has an active gleaning movement, wherein households with fruit-producing trees can register them, and others will assist in the harvesting and distribution of fruit the household cannot use. While gleaning started as grassroots action by groups such as Produce to the People: http://producetothepeople.org/about.html, it has become sufficiently mainstream that even the Department of Public Works has a gleaning program: http://sfdpw.org/index.aspx?page=1243. Other activists, who believe the treescape should be produce edible benefits, are "undoing civilization one tree at a time" by grafting fruit-producing branches onto ornamental trees. These "Guerilla Grafters" (http://guerrillagrafters.org/) hope to "turn city streets into food forests". While city officials have voiced concerns about this approach, many San Franciscans are charmed by this reclamation of the commons.
Many years ago I sat in a hospital waiting room. A boy, perhaps 10 years old, gazed longingly out the window at a fruit tree in the hospital courtyard. The boy was talking to himself about how he might obtain some of the tree's bounty, but the courtyard doors were locked. He said "you gotta be havin' fruit." Perhaps these strategies for linking accessible food to the city streetscape and the commons will allow that long-ago boy to pick the fruit of his desire.