Agroforestry Support Species for Cold Climates


A silk tree in my garden, serving as living trellis to arctic kiwifruit; also shade provider for
shade crops including currant, mayapple, fuki, and edible hosta. Also fixes nitrogen.

Rafter Ferguson’s recent excellent article “Permaculture for Agroecology” (PDF) challenges the permaculture movement to read up on what’s happening in related fields like agroecology and agroforestry. I’m particularly interested in learning from the well-established agroforestry practices of the tropics to see what might be applied in cold climates. I’ve been learning a lot about what species are used in cold-climate agroforestry as I research the book I’m writing. Here are some species being used on farms for practices like alley cropping, contour hedgerows, living fences, wind breaks, living trellises, and shade for crops. They serve as our alternative to multipurpose tropical trees like Leucaena and Gliricidia.

Many more species could be used for these purposes and undoubtedly are. I’m focusing here on species that are reported in the literature and those that I have personally used or witness to be used for these purposes. My primary sources are Mansfeld’s Encyclopedia of Agricultural and Horticultural Crops, Participatory Agroforestry Development in DPR Korea (PDF), and Agro-Ecological Farming Systems in China. Please share your successes, failures, and observations — and set up some formal trials!

Here I’m defining cold climate as boreal (USDA zones 1-3) and cold temperate (USDA zones 4-6), and warm temperate (USDA zones 7-8). These are place with real winters, outside of the subtropics. Arid means 0-250mm of rainfall (1-10″), semi-arid is 250-1000mm (10-40″), and humid 1000+mm (40″ or more). Species market with an asterisk (*) fix nitrogen.

Cold-Climate Superstars

Two species clearly emerge as the most multifunctional (or at least most widely used and written about; many other species are potentially as versatile).

Silk tree Albizia julibrissin


The attractive flowers of the multifunctional Albizia julibrissin.

Silk tree, or mimosa, is a beautiful small tree from E. Asia. It is hardy through USDA Zone 6 through the tropics, and likes semi-arid to humid conditions. Throughout the lowlands and highland tropics, Albizia species are important agroforestry crops. This one is for us! Silk tree fixes nitrogen and resprouts vigorously. It is used in alley cropping and contour hedgerow systems, crop shade, and serves as a windbreak.

False indigo Amorpha fruticosa

False indigo is native across North America, though it is mostly ignored here. In China and Korea it is an important agroforestry species. It is hardy to USDA Zone 3 through warm temperate, and handles semi-arid to humid conditions. In fact I have seen it grown in very dry high desert, and deeply flooded floodplains. False indigo is a multistemmed shrub, coppicing readily. It fixes nitrogen, and is used in alley crop, contour hedgerow, and windbreak applications.


False indigo is a very cold-tolerant multipurpose agroforestry legume

Alley Crop Species

Alley crop systems integrate rows of coppiced woody plants, usually nitrogen-fixers, with wider bands of annual crops. Some crop trees are also intercropped with annuals in alternating rows (like black walnut, pecan, and jujube), but here we are focused on alley crop plants that fix nitrogen to support the neighboring crops.

Albizia julibrussin*


silk tree


E. Asia


cold temperate to subtropical


humid
Amorpha fruticosa*


false indigo


N. America


boreal to warm temperate


semi-arid to humid
Hippophae rhamnoides*


seaberry


Eurasia


boreal to cold temperate


semi-arid to humid
Morus alba


White mulberry


E. Asia


cold temperate through tropical


semi-arid to humid


Contour Hedgerow Species

Contour hedgerows are essentially alley crops on slopes, planted on contour. They are an excellent erosion control strategy and over time can form living terraces. I suspect Cornus sericea would do a good job at this as well.


Contour hedgerow of elderberry in Mexico

Albizia julibrussin*


silk tree


E. Asia


cold temperate to subtropical


humid
Amorpha fruticosa*


false indigo


N. America


boreal to warm temperate


semi-arid to humid
Aronia melanocarpa


chokeberry


N. America


boreal to warm temperate


humid
Caragana microphylla*


Littleleaf peashrub


E. Asia


boreal to warm temperate


arid to semi-arid
Morus alba


White mulberry


E. Asia


cold temperate through tropical


semi-arid to humid
Sambucus canadensis


Elderberry


N. America to Mesoamerica


Cold temperate to subtropical


humid


Living Fence Species

Some of these come from cuttings like proper tropical living fences, while others are grown from seed.

Caragana arborescens*


Siberian peashrub


E. Asia


boreal to cold temperate


semi-arid to humid
Cylindropuntia spp.


Cholla


Americas


cold temperate to tropical


arid to semi-arid
Gleditsia triacanthos


Honey locust


N. America


boreal to subtropical


semi-arid to humid
Maclura pomifera


Osage orange


N. America


cold to warm temperate


semi-arid to humid
Morus alba


White mulberry


E. Asia


cold temperate through tropical


semi-arid to humid
Prinsepia utilis


Cherry prinsepia


E. Asia


cold temperate through tropical


semi-arid to humid
Prunus spinosa


Sloe


Europe


warm and cold temperate


humid


Windbreak

Cultivated to reduce the impact of wind on crops, livestock, or farm buildings.

Amorpha fruticosa*


false indigo


N. America


boreal to warm temperate


semi-arid to humid
Caragana arborescens*


Siberian peashrub


E. Asia


boreal to cold temperate


semi-arid to humid
Caragana microphylla*


littleleaf peashrub


E. Asia


boreal to warm temperate


arid to semi-arid
Elaeagnus angustifolia*


Russian olive


Eurasia


boreal to warm temperate


semi-arid
Elaeagnus umbellata*


autumn olive


Eurasia


cold to warm temperate


humid
Hippophae rhamnoides*


seaberry


Eurasia


Boreal to cold temperate


semi-arid to humid
Populus spp.


hybrid poplar


hybrid


boreal to warm temperate


humid to semi-arid
Populus nigra


black poplar


Eurasia, N. Africa


boreal to warm temperate


semi-arid to humid
Robinia pseudoacacia*


black locust


N. America


cold to warm temperate


semi-arid to humid
Salix purpurea


purple willow


Europe, An. Africa


boreal to warm temperate, humid


humid


Living Trellis

Cultivated to serve as the trellis on which to grow vine crops. In my own garden I use Albizia julibrussin and Amorpha fruticosa for this purpose.

Populus spp.


hybrid poplar


hybrid


boreal to warm temperate


humid to semi-arid
Populus nigra


black poplar


Eurasia, N. Africa


boreal to warm temperate


semi-arid to humid


Crop Shade

These crops intentionally cultivated to provide shade to crops that need it (like ginseng, coffee, etc.)

Albizia julibrussin*


silk tree


E. Asia


cold temperate to subtropical


humid
Alnus cordata*


Italian alder


Europe


cold to warm temperate


humid
Styphnolobium japonicum*


Japanese pagoda tree


E. Asia


cold temperate to subtropical


semi-arid to humid
Toona sinensis


fragrant spring tree


E. Asia


cold temperate to subtropical


humid

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8 thoughts on “Agroforestry Support Species for Cold Climates

  1. Wow. Thank you Eric for sharing these great compilations! Looking forward to integrating some of these into a Michigan landscape.

  2. Thanks for this interesting article. Do you know if any of these species has some tolerance to deer browsing ? Thanks.

  3. Thanks, Eric. Hidden in plain sight, it was. LOL.

    You and I may be in the same cold temperate as you define it but on a temperature basis this past winter, there’s a world of difference. From Dec thru Feb, the coldest you saw in Holyoake was around -11°F while we saw -19°F. Your average low temp was 15°F while mine was 5°F.

    Toona sinensis may survive in Holyoake but I can say it dies for me even when protected. Mimosa? I don’t even try.

    The point that I making that as the temp drops moving northwards into zone 5 and 4, the cold extremes in those zones reduce the options greatly. You can have 10 years where a plant survives the winter and then an extreme winter kills it. One needs to be careful in design not to accidently build in weakness. Testing so-called limits is a good thing but care is needed. I’m growing Osage orange on a test basis. It appears to have survived this winter with little dieback although it was covered by snow and escaped the unusual winds that we had this winter. Thus I’m still not committing to it although it’s certainly appears to have passed muster on a temperature basis.

    So far, my tree of preference given my winter temps is black locust – fast growing, coppiceable, nitrogen fixing, dappled shade, firewood, bee nectary.

  4. Thanks Eric for sharing all this data and for pointing the excellent article “Permaculture for Agroecology”.

    Was wondering if you publish your data under a free license such as creative commons BY SA ? It would be useful so the knowledge can spread and other resources can be built upon it in the same way linux or wikipedia were built because of open licenses.

    Btw, I just found today (serendipity?) a resource that intend to share knowledge about how to grow food forest under free licenses:

    http://www.onecommunityglobal.org/food-forest/

    Would be great if an they could use knowledge and data written by experts like you.

    cheers :)

  5. Hi DGG, black locust is great, Sibean pea shrub and Amorpha fruticosa are also excellent candidates for your climates. The goal of this article was not to list all of the potential species, but only those that are known to be used in farm-scale agroforestry in cold climates. A future article will include a full palette of species for usda zones 1-3.
    Hi Lilian, go ahead and consider this one creative commons. Eric

  6. Eric,

    I’ve got Siberian pea growing (started from seed) but it is slow to establish (for me at least) and extremely slow compared to black locust. I’ve not yet tried Amorpha fruticosa but will add it to my seed list for next year.

    We’ve experimented with red alder and had it over winter under snow cover. Who knows what drying north winds will do in the winter? We’ll see next year. I had expected it to be marginal here and it may yet be since its NA range is coastal British Columbia. Assuming it can handle our winters, we plan to coppice it to harvest the nitrogen that it fixes and add it to compost. We’ll also use it as a mulch since it releases nitrogen by leaching from foliage. And apparently, its roots are associated with ecto- and endo-mycorrhizal fungi. I plant to layer the tree to produce more trees and to harvest the soil from the layering bed as an inoculant elsewhere.

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