Agroforestry systems perform better than monocultures both economically and ecologically. They help landowners to diversify their income, improve soil and water quality, moderate microclimate, and reduce erosion. It also helps to improve habitats for wildlife, lower prevalence of pests and beautify the landscape.
The permanent plant coverage that agroforestry systems provide enhances soil organic matter and biological activity. Thus creating a closed-loop nutrient cycle which greatly reduces the need for maintenance, fertilizers or other external inputs. Furthermore, the release of nutrients from the decomposition of tree cuttings can be synchronized with the needs for nutrient uptake of the crops. Agroforestry systems date back thousands of years and differ greatly in design, depending on their purpose and context – they can appear as wilderness or be highly structured.
Agroforestry is also a critically important solution to climate change. According to Project Drawdown and the research of Dr. Paul Hawkin and team, an acre of agroforestry can achieve rates of carbon sequestration comparable to those of pure reforestation (almost 3 tons of carbon per acre, per year), with the added benefit of producing food and other crops or even livestock.
Why combine trees and agriculture in agroforestry?
Trees can form an integral part of a regenerative agricultural system. Some functions they provide include:
- Additional productivity compared to single-crop systems, producing food, fodder, fuel, fibers, building materials and medicines (often relieving pressure on natural forests)
- Maintenance or enhancement of ecosystem services such as water cycles, soil health and nutrient cycles, biodiversity, pest and disease control, and air purification
- Windbreaks and shelter for crops, animals and people
- Efficient use of ecological resources (water, light and nutrients)
- Climate mitigation and adaptation (sequestering carbon and building resilience to droughts and floods)
- Increased biodiversity and wildlife habitat
- Economic resilience through risk diversification
- Spiritual, cultural and social value, including the provision of a recreational landscape
What are the most common types of agroforestry systems?
Food forests are multi-layered gardens designed to mimic natural forest growth patterns to ensure better yield, maximum light exposure and low-to-no maintenance. They are most common in tropical and subtropical climates. These systems are typically small (less than an acre), domestic (used for subsistence rather than commercial purposes) and in many regions have deep cultural and historical significance. Food forests are often indistinguishable from a natural forest – indeed, they are designed to be highly diverse, complex forest ecosystems. Typically food forests have multiple edible layers that maximize horizontal and vertical space, including tree canopy, shrubs, perennials and annuals, crop roots and vines.
These systems are well suited to steep slopes and degraded croplands, land unattractive to more conventional approaches to agriculture. According to Project Drawdown, if an additional 50 million acres of multi-layered agroforestry were added globally by 2050, over 9 gigatons of carbon could be sequestered. It also makes sense financially – Project Drawdown estimates this increase would generate $710 billion in net profits globally on a $27 billion investment.
Food forests are significant (and ancient) in many regions of the world, including:
- The entire Amazon rainforest could be considered an ancient food forest – research has shown most edible species were planted by humans over 4,500 years ago
- Growing movement for use of agroforestry to grow oil palm in Brazil
- 2,000 year old food forest system in the Moroccan desert
- 5 million hectares in Indonesia
- 1.4 million hectares in Kerala, India
- Practiced in Mesoamerica for up to 13,000 years
- There is also increasing development of food forests in urban settings, in particular to serve food deserts, such as the Beacon Food Forest in Seattle, US.
There are also two great examples of food forests in The Netherlands: Den Food Bosch and Ketelbroek.
Silvopasture is an ancient method of combining animal production with trees – either the integration of trees into animal pasture, or the integration of animals into forest systems. Research suggests silvopasture far outpaces any grassland technique for counteracting the methane emissions of livestock and sequestering soil carbon. These systems can be non-commercial (community and socially-oriented), or commercial. They often include a wide range of tree crops and animals (including pigs, cattle, sheep, goats, and fowl). The most iconic example is perhaps the “dehesa” or “montado” of Spain and Portugal, where black pigs forage for acorns in oak forests that also provide shade and shelter. This multifunctional system is derived from the Mediterranean forest ecosystem. In addition to pigs it produces other products such as mushrooms, honey, cork and firewood.
Animal management is crucial to avoid tree damage by grazing or trampling. This may involve seasonal exclusion when trees are most vulnerable or rotational grazing. Grazing can control grass competition with trees for nutrients and reduce habitat for rodents that can damage trees. These systems can be savannah style (grassland ecosystems characterized by trees being sufficiently spaced so the canopy does not close) which are highly productive forage system for animals. Orchards are also common, especially with species such as sheep or geese.
Orchards often incorporate compatible understory species and even annuals. Specific species can be chosen for their function such as fruit production, wildlife attraction or nitrogen fixation.
There are also successful examples for mixed farming with rice, fish, ducks and water fern in four different regions in Indonesia.
According to Project Drawdown, pastures with trees sequester five to ten times as much carbon as those of the same size that are treeless, storing it in both biomass and soil. Silvopasture has significant financial benefits for farmers, too. Animal and forest products including timber, nuts, fruit and mushrooms generate income on different time horizons. Silvopastoral systems also help animals adapt to erratic weather and increased drought. If silvopasture expands to an additional 200 million acres by 2050, over 30 gigatons of carbon dioxide can be sequestered (almost 2 tons per acre per year). Farmers could also realize financial gains from revenue diversification of $700 billion globally on an investment of just over $40 billion to implement.
Do you want to learn more about the different agroforestry practices?
We have prepared a Primer for Farmers which explains exactly the different options and possibilities as well as where reNature Foundation can help you.
Silvoarable systems combine trees (or other woody perennial crops) with non-tree annual crops, and can be both non-commercial and commercial. They often include annual plants seen in many conventional farming systems, but can vary greatly with anything from fruit trees and vegetables, to grains and fodder crops. These systems often incorporate techniques and machinery used in monocrop commercial agriculture, such as when implementing alley cropping. Alley cropping is the practice of planting annual crops (eg, grain, cabbage, potatoes) between widely spaced rows (40-60 feet apart) of woody plants or trees, allowing easier fertilizing and weeding of crop rows while also retaining the benefits of intercropping. When the trees are pruned their cuttings are spread on the crop rows as mulch to protect the soil and add nutrients.
Denis Flores in France has the oldest established agroforestry system in Europe, with enormous top soil retention and flood mitigation benefits. Flores grows vegetables under rows of tall timber trees such as walnut, cherry and poplar, using their wood chips as an outstanding fertilizer and weed control for the vegetables.
Another silvoarable approach is the use of a keyline layout which maximizes the beneficial use of water resources by studying the natural flow of water on the land. An example is the Ridgedale Permaculture Farm in Sweden, where the keyline system involves strips of orchard trees and timber with annuals and pasture in lanes between. Both solar orientation and beneficial water distribution in the landscape were taken into consideration in the design.
Examples of silvoarable systems:
Are you interested in investing in Agroforestry?
We proof Agroforestry makes money. reNature Foundation connects farmers, communities and coops with companies and investors. We have several country based portfolios; Brazil, Mexico and Indonesia.