“If you look at roadside embankments, you might be able to see how trees connect with each other through their root systems. … Once connected, they have no choice but to exchange nutrients. They create what looks like a social network. … The reasons are the same as for human communities: there are advantages to working together. A tree is not a forest. … But together, many trees create an ecosystem … and in this protected environment, trees can live to be very old.”
— Peter Wohlleben (2015), The Hidden Life of Trees; excerpt from article on Downington, PA food forest (see link In The Public Space)
“The need to graze near most trees and shrubs also plays in the layout considerations hugely. If I could redo [Whole Systems Research Farm], I would vastly simplify the planting patterns and try wherever possible to lay out everything on contour in hedges. Even larger trees like apples and mulberries could work well in a hedge, I think. . . . In permaculture we seek the complex route – yet the most complex systems become almost unmanageable. On some fronts, and theoretically, unmanageability might be the desired state: the archetypal food forest, maintaining itself — all we need to do once it’s established is walk through and forage. I fell in love with this idea, and it got me into permaculture . . . But the fact is, I have yet to see a system even remotely close to this idea on a larger scale than the small backyard of maybe a quarter acre. … I happen to live on ten acres and need to figure out how to manage those ten acres with a high degree of restoration, productivity and resiliency.”
“Time and time again I’ve seen far more food per area come out of a well-managed thousand-square-foot garden than a poorly run fifty-thousand-square-foot [roughly 1 acre] farm.”
“A nut tree is simply more effective and efficient at converting sunlight and precipitation into value, over the long term, than any other technology humans have yet designed.”
— Ben Falk, The Resilient Farm and Homestead
“Multi-strata agroforests are forest-like systems that feature multiple layers of trees, often with the incorporation of herbaceous perennials, annual crops and livestock. . . . The tropical homegarden, an ancient multistrata agroforest system, dates back more than 13,000 years in Southeast Asia. . . At present such systems are rare in temperate climates. Given the very high carbon and other benefits, development of such systems should be a priority.”
— p. 100, Eric Toensmeier, The Carbon Farming Solution
Agroforestry practices that intentionally retain or plant trees on land used for crop production or grazing (Wiersum 1981, Nair 1983 in Gliessman Agroecology text)
Agrosilviculture trees combined with crops, e.g. alley cropping
Silvopasture trees combined with animal production, e.g. grazing ruminants, pastured poultry or pigs. May involve animals grazing beneath tree crops or plantation forestry trees; in existing woodlands and savannahs; or allowing spontaneous regrowth of woody plants (Toensmeier, p. 92, The Carbon Farming Solution). In fodder tree silvopasture the trees produce animal feed directly, e.g. nuts, fruits, acorns, woody pods, or leaves. The high tannin content from leguminous trees and shrubs reduces methane production from ruminant digestion [ref 22, p. 92, Toensmeier]. Two of the most common examples are Portuguese Spanish montado or dehesa systems, in which pigs, sheep and cattle graze under high-yielding acorn oaks (Quercus ilex) interplanted with cork oaks (Q. suber) and other crop trees.
Agrosilvopastoral a complex mixture of trees, animals and crops
Eric Toensmeier’s overview of tree-based systems in The Carbon Farming Solution include:
- Farmer-Managed Natural Regeneration developed by Tony Rinaudo in Africa; consists of permitting stumps and roots in farm fields to grow rather than continually suppressing them through tillage
- Contour Hedgerows and Terrace Edges using woody shrubs and perennials on contour to build and maintain terraces on sloped land, with annual crops grown on terraces
- Living Fences and Hedgerows replacing post-and-wire or other types of manufactured fencing with live trees and shrubs to act as fences; requires dense plantings, often coppicing or hedgelaying skills (interweaving growing branches), and often utilizes species with heavy thorns or dense, stiff vegetation
- Successional (annuals and short-lived perennials cultivated under new tree plantings) and Irregular Intercropping (trees scattered throughout cropland)
- Swidden landscapes managed as a mosaic of successional stages, beginning with cleared forest
- Fodder Tree Silvopasture, including Insect Fodder Systems
- Intensive Silvopasture extremely dense plantings of fodder trees, e.g. in Australia, Leucaena is commonly planted at 8-10k per hectare, that are then grazed to the ground by livestock and allowed to resprout through managed grazing rotations
- Fodder Banks and Pollarded (or Coppiced) Species livestock are confined, and fodder is harvested and brought to them; widely practiced on smallholder farms where grazing management is impractical
- Outdoor Barns and Living Corrals livestock enclosures made of living woody plants; living barns are “essentially windbreaks with small patches of forest to provide shelter” [ref 113]; green corrals are hedgerows or living fences of livestock-proof woody plants that are spiny, poisonous, dense and/or unpalatable
- Perennial Feed and Fodder for Storage hay from well-managed hay fields, tree hays (dried and stored tree foliage), perennial staple crops, e.g. leguminous pods; fermented silages from perennial fodders.
I use the Regrarians platform and the 10-layer Scale of Permanence when conducting a site assessment. For the Forestry design layer, we gather information on both existing and planned resources, including:
- Forest Types, e.g. existing native forest or historic forest patterns
- Integration Potential, i.e. capacity for native forest to be integrated into production systems (or vice versa)
- Orchards & Tree Crops, e.g. fruits, nuts, forage, fuel, fungi
- Production Forestry, e.g. timber primarily
- Shelterbelts and Windbreaks (note both potential and existing)
- Wildlife (species, prevalence, patterns of movement and biology)
- Livestock (species, requirements, contributions, integration potentials)
- Problem Species/Issues, e.g. invasives, old plantations or same-aged monoculture stands, diseases
(Use for citation only, and pulling the DOI: the links, since they were created in Google Docs, are all broken. I’ll be working on fixing this for this and past issues!).
Calfapietra, C., Gielen, B., Karnosky, D., Ceulemans, R., & Scarascia Mugnozza, G. (2010). Response and potential of agroforestry crops under global change. Environmental Pollution, 158(4), 1095–1104. https://doi.org/10.1016/j.envpol.2009.09.008
Maezumi, S. Y., Alves, D., Robinson, M., Souza, J. G. de, Levis, C., Barnett, R. L., Oliveira, E. A. de, Urrego, D., Schaan, D., & Iriarte, J. (2018). The legacy of 4,500 years of polyculture agroforestry in the eastern Amazon. Nature Plants, 4(8), 540–547. https://doi.org/10.1038/s41477-018-0205-y
Soto-Pinto, L., Anzueto, M., Mendoza, J., Ferrer, G. J., & de Jong, B. (2010). Carbon sequestration through agroforestry in indigenous communities of Chiapas, Mexico. Agroforestry Systems, 78(1), 39–51. https://doi.org/10.1007/s10457-009-9247-5
Sow, A., Seye, D., Faye, E., Benoit, L., Galan, M., Haran, J., & Brévault, T. (2020). Birds and bats contribute to natural regulation of the millet head miner in tree-crop agroforestry systems. Crop Protection, 132, 105127. https://doi.org/10.1016/j.cropro.2020.105127
Teague, W. R., Apfelbaum, S., Lal, R., Kreuter, U. P., Rowntree, J., Davies, C. A., Conser, R., Rasmussen, M., Hatfield, J., Wang, T., Wang, F., & Byck, P. (2016). The role of ruminants in reducing agriculture’s carbon footprint in North America. Journal of Soil and Water Conservation, 71(2), 156–164. https://doi.org/10.2489/jswc.71.2.156
Toensmeier, E. (2017). Perennial Staple Crops and Agroforestry for Climate Change Mitigation. In F. Montagnini (Ed.), Integrating Landscapes: Agroforestry for Biodiversity Conservation and Food Sovereignty (pp. 439–451). Springer International Publishing. https://doi.org/10.1007/978-3-319-69371-2_18
In The Public Space
- Eliza Greenman’s new venture HogTree, developing temperate climate, 7-month agroforestry production for the purposes of raising livestock entirely on fruit and nuts. See also her personal site and writings at www.elizapples.com.
- North America’s oldest food forest, Shelterwood Food Forest, is in Philadelphia, PA, and is a founding site for J. Russell Smith’s work in nut-bearing trees (see Books, below).
- The Overstory. To quote their introduction: “[A] free email agroforestry journal for practitioners, extension agents, researchers, professionals, students, and enthusiasts. One edition is sent each month focusing on a concept related to designing, developing, and learning more about trees and agroforestry systems. Focuses on trees and their roles in agriculture, natural ecosystems, human culture and economy.”
- Mark Shepard’s New Forest Farm, 106 broadacre perennial agriculture savannah, is an inspiring visual example of a polyculture homestead that produces at farm scale for some things through a long-running organic co-op. See this article in Permaculture Apprentice and his book Restoration Agriculture.
- Note: If your interested is piqued by his new book, Water for Any Farm, or more generally in learning keyline design in application to agroforestry and broadacre design in general, I recommend looking instead to Water for Every Farm (the original text) by Ken Yeoman or better yet — investing in Darren Doherty’s comprehensive field guide to land design, The Regrarians Handbook (see Chapters 2, Geography, and 3, Water, especially. Darren has worked extensively with the Yeomans family to fully understand and accurately apply keyline design principles and practicalities on literally thousands of landscapes. There is plenty of discussion on Shepard’s modifications of keyline design, and so while I think his systems are interesting and potentially yield much information from his experience, I look to and recommend the Regrarians platform and Yeomans for design education.
- Ben Falk’s Vermont homestead and design company, Whole Systems Research Farm and his book The Resilient Farm and Homestead are excellent resources for learning. I have heard mixed reviews of his PDC.
- Badgersett Research Farm in Minnesota conducts leading-edge research on the development of woody agriculture based on a variety of nut crops and grazing of coppiced tree plantings
- The Permaculture Research Institute has a number of good articles on tree crops, starting with this general overview and related topics including propagation, particular species of special interest (e.g. moringa), and more.
- The Agroforestry Podcast from The Center for Agroforestry at U Missouri. Note that U Missouri has an online graduate (MSc) program in agroforestry.
- Steve Gabriel on the Permaculture Podcast (episode 1322) and Urban Farm podcast (episode 370, 2018). Steve is an instructor at Finger Lakes Permaculture Institute, co-owns Wellspring Forest Farm and School, and is an extension office aide at Cornell University where he conducts research with Dr. Ken Mudge. He is also an author and co-author; see links below. There are lots of good additional resources in the notes section for both of these episodes, too.
- Rowan Reid, Heartwood: The Art and Science of Growing Trees for Conservation and Profit (2017)
- J. Russel Smith, Tree Crops: A Permanent Agriculture (1929) as ebook on SoilandHealth.org (public domain, free for distribution) and print at ThriftBooks (hardcover, $75) and Alibris (trade paperback, $16, updated 1953 version)
- Eric Toensmeier and Dave Jacke, 2005, Edible Forest Gardens (2 volumes, hardcover)
- Steve Gabriel
- (2018) Silvopasture: A Guide to Managing Grazing Animals, Forage Crops and Trees in a Temperate Farm Ecosystem
- with Ken Mudge, 2014, Farming the Woods
- Peter Wohlleben, The Hidden Life of Trees (2015)
- Gary Nabhan (2013), Growing Food in a Drier, Hotter Land
- And a whole list, from Agroforestry.org
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