- freely available
Sustainability 2018, 10(9), 3337; https://doi.org/10.3390/su10093337
- “Regenerative organic agriculture is marked by tendencies towards closed nutrient loops, greater diversity in the biological community, fewer annuals and more perennials, and greater reliance on internal rather than external resources.” .
- “Practices that: (i) contribute to generating/building soils and soil fertility and health; (ii) increase water percolation, water retention, and clean and safe water runoff; (iii) increase biodiversity and ecosystem health and resiliency; and (iv) invert the carbon emissions of our current agriculture to one of remarkably significant carbon sequestration thereby cleansing the atmosphere of legacy levels of CO2.” .
- “Unifying principles consistent across regenerative farming systems include: (1) abandoning tillage (or actively rebuilding soil communities following a tillage event); (2) eliminating spatio-temporal events of bare soil; (3) fostering plant diversity on the farm; and (4) integrating livestock and cropping operations on the land.” .
- Soil: Contribute to building soils along with soil fertility and health.
- Water: Increase water percolation, water retention, and clean and safe water runoff.
- Biodiversity: Enhance and conserve biodiversity.
- Carbon: Sequester carbon.
2. Agroforestry as a Regenerative System
2.1. Regenerative Characteristics of Example Agroforestry Practices
2.1.1. Alley Cropping
2.1.2. Forest Farming
2.1.3. Riparian Buffer
3. Relevant Certifications, Standards, and Guidelines
3.1. Agricultural and Forestry Certifications and Standards
- Recommend agroforestry as an option to achieve stated goals.
- Require agroforestry practices to achieve stated goals.
- Contain prescriptive criteria as to how agroforestry systems should be implemented, maintained, and measured.
3.2. Resource Conservation Guidelines
4. Approach to Standardization
4.1. Practices versus Outcomes
4.2. Organic as a Baseline Standard
5. A Standard for Regenerative Agroforestry
- Integration: The first of these characteristics is the integration of trees, shrubs, and other perennials within the cropping system, which is a fundamental feature of agroforestry, as stated in all agroforestry definitions. Perennials are more resilient to weather extremes and other environmental variations, imparting increased resiliency compared with annual crops [57,117]. There is evidence that with more extensive and deeper root systems, perennials can appreciably decrease erosion compared with annual cropping systems . They also store carbon in their above- and below-ground biomass, which accounts for their potential to sequester carbon.
- Density: The second important characteristic of agroforestry systems is the density of plants growing together in a stacked or multistory configuration. When optimized for a given environment and species mix, higher density plantings confer multiple regenerative benefits. High plant density builds soil by increasing organic matter production, which through leaf drop, root senescence, and pruning/cutting management can be left in place to add organic matter and mulch cover for the soil . High-density plantings can increase soil-holding capacity and decrease erosion , also potentially increasing biodiversity within the agroecosystem .
- Multistory: The third characteristic is a multistory configuration, which is a result of integrating many species. Multistory agroforests have a higher total light interception than single-layer canopies, and therefore have higher total primary production of biomass (higher photosynthetic conversion) [120,121]. The multistory aboveground structure of agroforests with diverse species composition are paralleled by root systems that occupy various soil depths and together form a network that efficiently captures nutrients before they can be carried away by water . The abundant leaf litter and herbaceous cover of multistory agroforests create capacity to minimize erosion . Various tree/shrub heights create greater habitat for more organisms, increasing biodiversity . Finally, multistory agroforests have been shown to have a high capacity for carbon sequestration, especially in their early years [122,123].
- Multiple species: The fourth characteristic is the inclusion of multiple species and varieties, which is related to plant density and multistory structure. Increased species diversity increases overall biodiversity of the system. Having a large number of species also confers resiliency by ensuring that ecological niches are occupied even after weather extremes and other disturbances [57,124]. Chisholm et al.  state, “As species richness increases, productivity and biomass of the system also increase.”
- Integration: Presence of trees, shrubs, and perennials integrated into a farming system.
- Density: Plants per unit area (horizontal structure).
- Multistory: Strata represented in the layered structure and root systems (vertical structure).
- Multiple species: Number of plant families, genera, species, and varieties over time (temporal succession).
Conflicts of Interest
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|Certification/Standard 1 (Standard Owner)||Scope||Recommends Agroforestry||Requires Agroforestry Practices||Contains Prescriptive Agroforestry Criteria|
|Bird-Friendly Coffee (Smithsonian Migratory Bird Center) [87,88]||Int’l||Y||Y||Y|
|Certified Naturally Grown (Certified Naturally Grown) ||U.S.||N||N||N|
|Demeter Biodynamic® Production Standards (Demeter-International) ||Int’l||Y||N||N|
|Forest Garden Products (International Analog Forestry Network) ||Int’l||Y||Y||N|
|GLOBALG.A.P. (GLOBALG.A.P.) ||Int’l||N||N||N|
|IFOAM Standard (IFOAM-Organics International) ||Int’l||N||N||N|
|PCO Verified Forest Grown (Pennsylvania Certified Organic) ||U.S.||Y||Y||N|
|Regenerative Organic Certification (Regenerative Organic Alliance) ||U.S.||Y||N||N|
|Rainforest Alliance Sustainable Agriculture Standard (Rainforest Alliance) ||Int’l||Y||N||Y|
|USDA Organic (USDA National Organic Program) ||U.S.||N||N||N|
|UTZ Standard (UTZ) ||Int’l||Y||N||N|
|Forest Management Certifications|
|American Tree Farm System (American Forest Foundation) ||U.S.||N||N||N|
|Forest Stewardship Council Forest Management Certification (Forest Stewardship Council) [99,100]||Int’l and U.S.||N||N||N|
|Sustainable Forestry Initiative North American Program (Sustainable Forestry Initiative) ||U.S. and Canada||N||N||N|
|Criteria Measurement||Smithsonian Migratory Bird Center’s Bird Friendly Coffee [87,88]||Rainforest Alliance Sustainable Agriculture Standard |
|1. Presence of trees, shrubs, and perennials||≥10 woody species (in addition to the predominant shade trees or “backbone” species). At least 10 of these should represent 1% or more of all individuals sampled and be dispersed throughout. Backbone species must be native. ||Incorporation of native trees as border plantings and barriers around housing and infrastructure (e.g., live fences, shade trees, and permanent agroforestry systems).|
|2. Plants per unit area||≥40% tree/shrub cover, measured during dry season after pruning.||Minimum total canopy cover of 20–40%, depending on geographic region.|
|3. Layers represented in the tree/shrub structure||≥12 m (40 ft) height of the backbone species. Preferably three layers or strata : |
a. The layer formed by the backbone species and other trees of that size;
b. The taller emergent species comprised of native trees of the natural forest;
c. Understory made up of shrubs and small trees or plants.
The emergent and understory strata each should account for 20% of the total foliage volume present. The remaining 60% of the foliage volume should be the principal canopy. 
|Not explicitly given.|
|4. Number of woody perennial (trees, shrubs, palms, etc.) families, genera, species, and varieties||Requirement same as noted in criteria area #1. The total floristic diversity is the sum of all woody and herbaceous species counted in the sampling. ||The tree community consists of 5–12 native species per hectare (per 2.5 acres) on average, depending on the shade-tolerant crop being grown.|
|5. Additional criteria||Leaf litter should be present; no minimum percentage required, which, together with living ground cover, keeps the soil covered . Weeds/herbs/forbs should be present. Living fences and buffer zones along waterways should be present. Should qualify at least for the category “traditional polyculture” (the more diverse category of the polyculture systems). Must have current organic certification by a USDA-accredited certification agency. ||The farm must use and expand its use of vegetative ground cover to reduce erosion and improve soil fertility; structure and organic material content, as well as minimize the use of herbicides.|
|Criteria Measurement||Mixed Agroforest Specification (Pacific Islands Area) ||Riparian Forest Buffer (Illinois) ||Silvopasture (Kentucky) |
|1. Presence of trees, shrubs, and perennials||“Mixed Agroforests” are described as small-scale tree and shrub plantings.||Trees and/or shrubs located adjacent to and up-gradient from watercourses or water bodies.||Use trees and forages (shrubs where desired) that are adapted to the climate, soil, and biological conditions of the site and compatible with its planned use and management.|
|2. Plants per unit area||Tree/shrub counts must be ≥1050/ha (≥425/ac), including ≥62/ha (25/ac) tall stature trees. The balance must be short-stature trees or shrubs. Specific guidelines are given in tabular form for minimum number of species and structural diversity.||The location, layout and density of the buffer should complement natural features, and mimic natural riparian forests. Initial plant densities for trees and shrubs should be based on their potential height, crown characteristics and growth form, in addition to planting objectives.||Tree density at planting should be approximately 500–1000/ha (200–400/acre) for conifers, or 250/ha (100/acre) for black walnut, black locust, or pecan. Throughout the rotation, trees will be thinned in order to maintain understory-overstory balance that accommodates the producer’s goals.|
|3. Layers represented in the tree/shrub structure||High diversity in the planting arrangement of different genera and structure (height) at maturity, and may include tree, shrub, and vine. A minimum of two layers (tall and short stature trees/shrubs) are required.||Manage the dominant tree canopy to maintain maximum vigor of overstory and understory species. Periodic thinning and/or prescribed burning may be necessary to allow adequate light to reach the forest floor to maintain a good cover of grasses and forbs.||Manage trees, forages, and shrubs as needed to provide appropriate light conditions for forages, and shade/shelter conditions for livestock. Pruning needed to achieve the desired canopy type for production of fruits, nuts, and timber.|
|4. Number of woody perennial (trees, shrubs, palms, etc.) families, genera, species, and varieties||a. 6 woody plant genera or more depending on field size;|
b. ≤50% that produce non-timber forest products—any number of timber-producing trees are allowed;
c. A minimum of 20% as native species (may be timber producing).
Limitations: Individual plant genera that produce non-timber forest products may be planted in pure or contiguous clumps not to exceed five trees or 20 shrubs/vines. Different clumps of the same genera shall be separated by the maximum space feasible given overall species selection and land area of a given agroforest.
|No single species will make up more than 50% of the total number of species planted. Favor tree and shrub species that have multiple values such as those suited for timber, nuts, fruit, florals, browse, nesting, and aesthetics.||None specified.|
|Standard Criteria||Criteria Measurement||Description of Measure||Criteria Threshold|
|1. Integration||Presence of trees, shrubs, and other woody perennials.||Annuals have an essential early successional role to play in agroforestry, while the long-term structure of the system emphasizes both woody and herbaceous perennials.||≥40% cover by trees/shrubs, allowing transition time from open field. Individual practices (e.g., windbreak) may require higher cover for acceptable resource conservation functionality.|
|2. Density||Woody perennials per unit area.||This measure ensures continuous soil cover for erosion control, capture of nutrients, and weed suppression.||≥5 woody perennials per 100 m2 (1080 ft2), plus herbaceous cover and mulch.|
|3. Multistory||Layers occupied in the agroforest structure and root systems.||Based upon five potential vegetation layers (emergent, upper canopy, lower canopy layer or understory, shrub, and herbaceous) occupied per unit area.||≥2 woody perennial layers per 200 m2 (2160 ft2), plus the herbaceous layer and mulch.|
|4. Multiple species||Number of woody perennial (tree, shrub, palm, etc.) families, genera, species, and varieties.||A measure of biodiversity intentionally planted or protected in the agroforest.||≥8 plant families, genera, species, and/or varieties of woody perennials per 100 m2 (1080 ft2) present throughout the life of the agroforest. Pure or contiguous clumps not to exceed 3 trees or 10 shrubs/vines of a single species. Different clumps of the same species to be separated by minimum 3 times their maximum canopy diameter.|
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