What is Agroforestry?
Agroforestry is an intensive land management system that optimizes the benefits from the biological interactions created when trees and/or shrubs are deliberately combined with crops and/or animals.
The benefits created by agroforestry practices are both economic and environmental. Agroforestry can increase farm profitability in several ways:
- The total output per unit area of tree/crop/livestock combinations is greater than any single component alone.
- Crops and livestock protected from the damaging effects of wind are more productive.
- New products add to the financial diversity and flexibility of the farming enterprise.
Agroforestry helps to conserve and protect natural resources by, for example, mitigating non-point source pollution, controlling soil erosion, and creating wildlife habitat. The benefits of agroforestry add up to a substantial improvement of the economic and resource sustainability of agriculture.
Agroforestry practices are intentional combinations of trees with crops and/or livestock which involve intensive management of the interactions between the components as an integrated agroecosystem. These four key characteristics - intentional, intensive, interactive and integrated - are the essence of agroforestry and are what distinguish it from other farming or forestry practices. To be called agroforestry, a land use practice must satisfy all of the following four criteria:
- Intentional: Combinations of trees, crops and/or animals are intentionally designed and managed as a whole unit, rather than as individual elements which may occur in close proximity but are controlled separately.
- Intensive: Agroforestry practices are intensively managed to maintain their productive and protective functions, and often involve annual operations such as cultivation, fertilization.
- Interactive: Agroforestry management seeks to actively manipulate the biological and physical interactions between the tree, crop and animal components. The goal is to enhance the production of more than one harvestable component at a time, while also providing conservation benefits such as non-point source water pollution control or wildlife habitat.
- Integrated: The tree, crop and/or animal components are structurally and functionally combined into a single, integrated management unit. Integration may be horizontal or vertical, and above- or below-ground. Such integration utilizes more of the productive capacity of the land and helps to balance economic production with resource conservation.
A wide range of agroforestry combinations may be grouped into five basic types of practices: (1) alley cropping, (2) windbreaks, (3) riparian buffer strips, (4) silvopasture, and (5) forest farming.
This practice combines trees, planted in single or grouped rows, with agricultural or horticultural crops which are cultivated in the wide alleys between the tree rows. High-value hardwoods are typically grown in alley cropping combinations. Annual crops (e.g., row crops, forages and vegetables) cultivated between rows of nut or fruit trees provide extra income before the trees come into bearing and early in the long-term timber rotation. Depending on tree spacing, short-rotation tree may be interplanted with annual crops. Alternatively, short rotation woody crops may be interplanted within plantations of longer-rotation timber trees.
Windbreaks are planted and managed as part of a crop or livestock operation to enhance crop production, protect livestock, and control soil erosion. Field windbreaks are used to protect a variety of wind-sensitive row, tree and vine crops, to control erosion, and to provide other benefits such as improved bee or other insect pollination of crops and wildlife habitat. Feedlot windbreaks help reduce animal mortality, feed and water consumption, and odor. A special type of multi-row windbreak ("timberbelt") is managed both to protect crops or livestock on a continuous basis, and to produce timber or biomass.
Riparian Buffer Strips
Riparian buffers consist of strips of perennial vegetation (tree/ shrub/grass) planted between cropland or pastures and streams, lakes, wetlands, ponds, or drainage ditches. They are managed to reduce runoff and non-point source pollution from agricultural activities on adjacent lands by trapping sediment, filtering excess nutrients, and degrading pesticides. They can also stabilize streambanks, protect floodplains, enhance aquatic and terrestrial habitat, improve landscape appearance, provide harvestable products, and function as a windbreak in some situations.
This practice combines trees with forage (pasture or hay) and livestock production. The overstory tree component provides shade and wind shelter. In plantations of softwood or hardwood trees managed for timber or short-rotation trees, grazing provides a source of income during the early years of the rotation. Some nut and fruit trees areas may also be grazed to produce income before the trees begin bearing. Silvopasture is different from traditional forest or range management because it is intentionally created and intensively managed.
This practice utilizes a forested area for producing specialty crops which are sold for medicinal, ornamental or culinary uses. Shade tolerant crops such as ginseng, decorative ferns, orchids or mushrooms are intensively cultivated under a forest cover that has been modified to provide the correct level of shade. Suitable understory crops are those that grow naturally under forest conditions, or are adaptable to the edaphic and microclimatic conditions of the site. Forest farming can provide annual/regular income either before, or as an alternative to, harvesting the trees for wood products.