Urban Food Forests
Alley Cropping
This practice combines trees planted in single or multiple rows with agricultural or horticultural crops cultivated in the alleyways between the tree rows. High‐value hardwoods such as oak (Quercus sp.), walnut (Juglans sp.), chestnut (Castanea sp.) and pecan (Carya illinoensis (Wangenh.) K. Koch) are favored species in alley cropping practices, and many can provide high‐value lumber or veneer logs. Crops grown in the alleys, and nuts from walnut, chestnut and pecan trees, provide annual income from the land while the longer‐term wood crop matures (Gold, 2019). When specialty crops such as herbs, fruits, vegetables, nursery stock, or flowers are grown in the alleys, the microclimate created by the trees enables the economic production of these sensitive high‐value crops in stressed environments.
Silvopasture
This practice combines trees with forage (pasture) and livestock production. Silvopasture can be established by adding trees to existing pasture, or by thinning an existing forest stand and adding (or improving) a forage component (Jose et al., 2017). The trees are managed for high‐value sawlogs, and at the same time they provide shelter for livestock, protecting them from temperature stresses and reducing food and water consumption. Forage and livestock provide short‐term income at the same time a crop of high‐value sawlogs is being grown, providing a greater overall economic return from the land.
Forest Farming
High‐value specialty crops are cultivated under the protection of a forest overstory that has been modified and managed to provide the appropriate microclimate conditions. Shade‐tolerant specialty crops like ginseng (Panax quinquefolium L.), log‐grown shiitake mushrooms (Lentinula edodes (Berkeley) Pegler), decorative ferns and spring ephemerals grown in the understory are sold for medicinal, botanical, food, decorative and handicraft, and landscaping products. Overstory trees are managed for high‐value timber or veneer logs.
Urban Food Forests
In addition to the five recognized practices, there is an emerging, sixth agroforestry practice. Urban Food Forests, have gained considerable attention over the past decade (Lovell, 2010; Clark and Nicholas, 2013; Bukowski and Munsell, 2018; Park et al., 2019). Urban Food Forests are defined as: i) The intentional use of perennial food‐producing plants to improve the sustainability and resilience of urban communities (Bukowski and Munsell, 2018); 2) A food forest is an edible, perennial, polyculture system that is designed and managed to mimic multistory forest structures and to function like a natural, self‐sustaining forest (Park et al., 2018). The term food forest signifies an intentionally designed, highly integrated community of plants that has various vertical and horizontal plants and root layers that collectively provide edible products (Bukowski and Munsell, 2018). Urban food forestry is an emerging multifunctional and interdisciplinary approach to increasing urban sustainability and resilience, particularly where food security is concerned, and provides a starting point for bridging gaps in knowledge and practice between urban agriculture, urban forestry, and agroforestry. Also, as noted in Bukowksi and Munsell (2018), another commonly used term is community food forests.
Clark and Nicholas (2013) note that urban food forestry is a viable and important strategy to address multiple sustainability challenges (e.g., food security, climate change, and poverty), to contribute to human health by increasing affordable public access to and consumption of nutrient dense foods to combat hunger and obesity, and can be also used to promote sustainable urban development through providing enhanced ecosystem services.
Is it Agroforestry?
A key concern in developing agroforestry nomenclature for the United States and Canada is overlap and confusion with mainstream land use management disciplines, for example forestry, agriculture, and livestock production. A fundamental need was to develop a definition and criteria that would effectively distinguish practices that are agroforestry from those that are not (Garrett et al., 1994). Application of the four criteria defining agroforestry (intentional, intensive, integrative, and interactive) provides the key to determine what is and is not an agroforestry practice. Using these criteria, we have the basis to explain how variations of common land use practices can be properly described as agroforestry. The following examples are agroforestry because they satisfy all four of the criteria defining agroforestry.
Special Forest Products
Deliberate cultivation of an understory specialty crop beneath a forest canopy that has been modified and managed to provide the appropriate microclimate conditions in the understory is an example of forest farming (e.g., woods cultivated or wild simulated ginseng). The practice is created by design, is intensively managed, is integrated, and beneficial interactions are utilized. Thus, it is agroforestry, as contrasted to the gathering of naturally‐occurring, unmanaged, specialty products (e.g., wild ginseng) from a natural forest stand.
Log‐grown shiitake mushrooms, deliberately cultivated under the shade of the forest canopy is a legitimate forest farming practice. The practice is created by design, is intensively managed, is integrated, and beneficial interactions are utilized. Thus, it is agroforestry, in contrast to the production of shiitake on indoor sawdust bales which yields a similar (but not nutritionally identical) product but does not qualify as forest farming.
Nut Plantations and Fruit Orchards
When nut or fruit culture (i.e., planted in a plantation or orchard format) is combined with row crop or forage production, it is alley cropping (Gold, 2019). Crops grown in the between‐row space can be changed over time to minimize competitive effects and/or adjust to changing market conditions. Windbreaks can be established to protect orchards in exposed, windy areas. They slow the wind, reduce water use, improve insect pollination, and increase pesticide use efficiency. In each case, the components are deliberately integrated and intensively managed within the plantation or orchard.
Managed Intensive Rotational Grazing
When trees are added to an existing pasture and the resulting area is managed for timber, forage and livestock, it is the agroforestry practice of silvopasture. The components are deliberately integrated and managed by design to enhance the biophysical interactions among components. Both the timber and forage components are designed to minimize competition and maximize complementarity. Neither opportunistic forest grazing nor grazing cattle without management within a plantation are agroforestry; both can be destructive to the forest, tree, and forage resources.
Agroforestry in the Landscape
A final issue to discuss is mosaics of monocultures in agricultural landscapes. Common features of agricultural landscapes throughout the United States and Canada are single‐crop farm fields, woodlots and tree plantations, wetlands, and grazing lands. A physical proximity does not constitute agroforestry at the landscape level because there is no intentional integration and there is minimal interaction among components. In contrast, an agricultural landscape that contains windbreaks
