plantings including permanent woody vegetation strategically placed to maximize conservation benefits and create biophysical interactions with other components of the agricultural system, clearly demonstrates agroforestry at a landscape scale. The subject is discussed further in Table 2–3, which outlines agroforestry concepts.
Table 2–3. Agroforestry concepts.
| Concepts/Comments |
| Cascades of benefits are derived from beneficial process‐level biophysical interactions created when trees and/or shrubs are deliberately combined with crops and/or livestock. |
| Additional benefits are often derived from component integration when compared with traditional, segregated (agriculture and forestry) production. Through intensive and careful management, desired interactions are optimized and undesirable interactions are minimized. Agroforestry practices introduce, restore, and enhance biological diversity and agroecosystem resilience at field, farm, watershed and landscape levels. |
| For many people, enhanced biodiversity is considered a benefit, e.g., increased wildlife; however, in agricultural regions, biodiversity must be managed to obtain desired effects like enhancement of selected fish, wildlife, and plant species. The challenge is to determine the type, amount and distribution of species that will provide an adequate level of desired benefits. |
| Agroforestry contributes to integrated pest management by creating favorable habitats and microclimates to enhance the extent and effectiveness of natural pest controls. |
| Agroforestry is an essential component of effective conservation buffers creating positive impacts upon steep slopes, highly‐erodible soils and collapsing streambanks. |
| Agroforestry contributes to the maintenance of soil quality and productivity by keeping soil in place, enhancing nutrient absorption and cycling, intercepting water‐borne pollutants, improving water filtration and retention capacity, and reducing flood damage. |
| Agroforestry increases the productive area of the farm by expanding use of vertical and horizontal space above‐ and below‐ground and fully exploiting the diversity of useable niches. |
| Agroforestry practices permit fuller use of the soil profile, maximize use of photosynthetic radiation, and lengthen the growing season. |
| Agroforestry practices exploit additional field scale niches including border areas, marginal sites (rocky, infertile, too wet or dry) and steep slopes. |
Departures from Traditional Agroforestry Nomenclature
There is obvious inconsistency in the nomenclature used to describe the six categories of agroforestry practices. In the United States, Canada and abroad, efforts have been made to clarify definitions and nomenclature in agroforestry (Table 2–1). Mantau et al. (2007) offer a thorough discussion of the concepts of classification and nomenclature with regard to non‐timber forest products while Sinclair (1999) proposes a general classification of agroforestry practices. In the United States and Canadian nomenclature, two of the practices are named on the basis of function (windbreaks, and riparian and upland buffers), the names of two are based on the adoption of popularized names (forest farming, urban food forests).
As previously discussed, the nomenclature also departs from the systems terminology developed for tropical agroforestry and temperate agroforestry in other countries. Growing trees, crops, and animals in mixtures is a long‐standing tradition of tropical farmers. Tropical agroforestry evolved from these age‐old customs as well as more recent tropical agriculture paradigms of the 1960’s and 1970’s known as “cropping systems” and later as “farming systems” (Hildebrand, 1990). Subsequently, the nomenclature of tropical agroforestry tree, crop, and animal combinations was defined by the International Center for Research on Agroforestry (Lundgren and Raintree, 1982). During this definition phase for tropical agroforestry, a great deal of effort went into development of classification methodology. Classification and descriptive criteria were based on the situation and intended purpose to which agroforestry was being applied (Sinclair, 1999). The history of agroforestry classification has been reviewed and the five approaches to classify tropical agroforestry have been summarized (Nair, 1993; Atangana et al., 2013).
Nature of Components
Agrisilviculture describes crop–tree combinations, silvopasture describes tree–livestock combinations, and agrosilvopasture, describes crop–tree–livestock combinations.
Arrangement of Components
This criterion denotes whether the components exist simultaneously, overlap during part of a rotation, or follow in a prescribed sequence.
Functional Role
The primary use, production or conservation, is a common approach to classifying tropical agroforestry.
Agroecological Zone
The use of agroecological zones to classify agroforestry is based upon a characterization of climate, vegetation, and land‐use capability, usually a region within a country, for example, humid lowlands, arid or semi‐arid lands, or highlands.
Social and Economic Features
This approach uses scale of production and level of technology, for example, subsistence, intermediate, or commercial to classify agroforestry.
Perspectives on U.S. and Canadian Agroforestry
Finally, one must recognize that there are two distinct perspectives on agroforestry in the United States and Canada, and it is important to distinguish them from a nomenclature standpoint.
Agroforestry at the Practice Level
For field practitioners and landowners to understand, accept, and use agroforestry, it must be as pragmatic, market‐focused, and adoptable as possible. Complex “systems terminology” is not acceptable. Consequently, a simple agroforestry nomenclature has been developed to make agroforestry practices compatible with, and complementary to, agricultural practices. The bottom line for agroforestry to succeed over most of North America is that it must be accepted and used within the agriculture community.
Agroforestry at the Science Level
Within the scientific community, agroforestry concepts have much in common with sustainable agriculture, agroecology, regenerative agriculture, and agroforestry in the rest of the world. Common goals are to conserve the natural resources upon which agriculture depends, minimize the environmental impacts of agriculture, maintain productivity and profitability, and provide for people’s economic and social needs (Fig. 2–1). At the science level, it is more important to focus on agroforestry concepts and their underlying process level functions, and less important to debate nomenclature.
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