Syntropic Agroforestry

Background

Naturally I read about what I'm interested in, so with tree-based agriculture I started out reading J. Russell Smith's Tree Crops - A Permanent Agriculture, then continuing on to Mark Shepard's Restoration Agriculture, Robert Hart's Forest Gardening, Martin Crawford's Creating a Forest Garden, and Dave Jacke & Eric Toensmier's Edible Forest Gardens. Then I did some deep dives into the annals of The Northern Nut Growers Association, and NAFEX (North American Fruit Explorers). All this time I was watching videos and listening to podcasts with other tree crops growers who have read all that stuff and put it into practice - Stefan Sobkowiak, Sean Dembrowski, Akiva Silver, Eliza Greenman, Steven Edholm. Lucky for me I've been able to learn from the many lifetimes of information put out by caring, passionate, and dedicated people for whom eating food off of trees that they've grown is totally their jam.

At some point during this journey I overheard the word that ties it all together - Agroforestry. With this term in hand, I spent the covid years of 2020 through 2023 researching everything I could about agroforestry, in all its different forms and combinations. Turns out there's a lot of tree crop adjacent stuff going on you'd never think of unless you saw someone else doing it, like being a moss farmer or raising basket willows or raising flowering trees and selling the blossoms to flower shops. Agroforestry is a big tent, everyone's welcome, and I like the simple description of it put forth by The Savannah Institute: "Agroforestry is planting trees on farms on purpose."

Throughout my study of agroforestry I kept seeing thumbnails of videos with titles like "Syntropic Agroforestry Brazil" that almost always featured jungle scenes with banana leaves or palm fronds. For some reason I didn't click on them, probably because I live in a very cold climate and thought they were irrelevant to my situation, like "well it's tropical plants and 'tropic' is in the name, so it's probably just about farming in the tropics." And also from all my years doing permaculture stuff, the term syntropic sounded just like another hippiesque neologism. 

So after several years of learning everything I could find on agroforestry and more or less becoming an expert on the topic, one day in late winter or early spring of 2023 I was bored and was just like, "ok, I keep seeing these videos come up in my feed, what the hell is syntropic agroforestry?" So I started watching some videos and it became very obvious very quickly that syntropic agroforestry was the most sophisticated and advanced approach to implementing agroforestry systems, both in terms of theoretical understanding and practical on-farm reality. In so many ways it "put it all together," from forest succession dynamics, to species selection, to tree establishment and long term management, tree-to-tree interactions, food system design, forest regeneration, etc. And it wasn't just a next level to agroforestry, but rather something deeper and more fundamental that applies to all the many faces of agroforestry. Syntropic agroforestry reveals a deeper understanding of how it all goes together, and once you see it you can't unsee it and you're just like, "OMG this is so obvious and it makes so much sense, I can't believe someone didn't put this all together sooner." 

What is Syntropic Agroforestry?

It's difficult to boil it down into few words, but syntropic agroforestry is a method of tree farming based on an understanding of forest succession, plant lifecycles, and the strata or layer that a plant occupies relative to the other plants above or below it. Syntropic agroforestry systems are often planted from seed (small transplants and cuttings can be used, but direct seeding is preferable) at a high level of density and diversity, up to 40 or 50 trees and plants per square meter. Once a syntropic agroforestry system is planted, the farmer manages the system through disturbance, pruning and managing the vegetation in a way that mimics the disturbance that naturally occurs over time in forest succession, but the syntropic farmer does it in a thoughtful targeted way to accelerate the growth of their desired species. The result is that diverse agroforestry systems can be created and brought into production much faster than typical food forests, orchards, or alley cropping systems planted with young trees that are left to mature at their own rate.

With forest succession, there's a well-studied sequence of transformations from bare soil all the way to climax forest, which can take many decades, to hundreds or even thousands of years. It is an ongoing process. Many are familiar with the "Old Field" theory of forest development, wherein old agricultural fields are abandoned and they eventually turn into forests. When left to nature's processes, old fields naturally give rise to a sequence of weeds, grasses, bushes, shrubs, and trees (along with their associated insects and animals), eventually transforming into a forest from what started as bare soil. For the farmer with an open field wanting to raise tree crops that naturally occur in a forest or forest edge, they can't simply plant them by themselves in a field and expect them to thrive, because the prerequisite conditions for those crops don't yet exist. But using the methods of syntropic agroforestry the farmer can speed-run forest succession toward their target crops by intentionally planting the whole sequence of plants that would naturally appear over decades or hundreds of years. Once planted, the farmer can then manage that sequence of plants at an accelerated rate, spending a few years at each stage of succession rather decades or centuries as would normally be the case if left to occur naturally. 

Within each stage of forest succession there are plants of various lifecycles (ie how long a plant lives - annuals, biennials, short lived perennials that live for 5 to 10 years, and long lived perennials that can grow for centuries). In the the early stages of succession the system is dominated by weeds and grasses that may only live for one or two years, and in later stages the system is more heavily comprised of trees and shrubs and herbs that can live for many years. For farmers working with new plantings in open fields, short lifecycle plants are used to create and maintain the conditions that give rise to longer lifecycle plants. In practice, you use annual plants like weeds, annual crops, and herbs to enrich the soil and create that initial "canopy" under which seedlings of medium and long term trees and shrubs can germinate and be protected during their juvenile years. Often such a planting is carried out with seeds and plants of a diverse mix of lifecycles, and they are all planted together at the same time. By placing "all the players on the field at the start of the game," such a planting ensures that the lifecycles within the stages of succession proceed in a continuous manner, and that as the conditions change over time the plants making up the next stage of succession are already growing in the right place at the right time.

It is critical that the syntropic farmer be aware of the different spaces and relationships that plants occupy amongst one another, as well as the different amounts of light that various trees and plants need during the stages of their lives, which together defines the layer or strata that a plant occupies in the system, from small shade-loving groundcover plants all the way up to large sun-loving canopy trees. A classic example of this that many are familiar with is the three sisters garden, whereby corn, beans, and squash are planted together so that the squash shades the ground and conserves soil moisture, the corn provides a trellis for the beans and some shade for the squash, and the beans provide nitrogen for the corn and squash. Each plants occupies their own space, and they functionally complement one another. By making a dense planting all at once combining one plant from each strata of every successional stage, the tree farmer can design a long term agroforestry system that produces food from the very beginning all the way to many decades later, without having the trees and plants competing with each other for light and space. What is to be avoided is planting two trees of the same strata and same successional stage right next to each other (for example an apple and a pear), as those trees will grow at the same rate and get in each other's way, and neither will be very productive. 

The diversity and density of syntropic plantings takes the guesswork out of selecting the best plants for the site - by planting hundreds of seeds of a dozen or more species into a square meter, the best plants will make themselves obvious and thrive in your conditions, and the ones that aren't suited will struggle. So then you just prune out the weak and crappy ones and you're left with true winners. Direct seeding of trees ensures that the root systems are never damaged by digging, which greatly benefits tap-rooted trees. Direct seeded trees and plants also never experience transplant shock, which can really harm some trees or even kill them if the transplanting is done improperly or at the wrong time of year. Additionally, such a dense planting completely fills the space, ensuring that 100% of the available sunlight is captured. Furthermore, the abundance of vegetation provides ample leaf litter to the ground directly below, feeding the soil and the trees just like in a forest. To further aid in the production of mulch, species are included that can be regularly cut back so that the trimmed material provides an everlasting source of mulch; these species are often referred to as "biomass species" or "support species" and they are typically grown at a rate of one support tree for every productive fruit tree. 

Why You Should Try Syntropic Agroforestry

Trees grown in syntropic plantings grow faster, and have few problems with pests and diseases because they receive the mutual aid provided by being surrounded by aromatic herbs, nitrogen fixing plants, and other shade or support species. Trees grow best in the forest, so if you want your trees to grow the best that they can, it makes sense to mimic forest conditions to get them off to a good start. Moreover, the density and diversity of syntropic agroforestry systems elevate a planting beyond mere orchard and gardens, effectively creating small-scale novel ecosystems where a broad range of insects and animals can find habitat. The original goal under which syntropic agroforestry was created was to find a way to restore forests while also making a viable living for the farm, in essence using farming to do ecological restoration.

Syntropic agroforestry provides a more comprehensive and wholistic understanding of what makes trees, plants, and ecosystems thrive. There are many finer points to syntropic agroforestry that I've left out of this article, but I'll cover them in the next one. 

Thanks for reading,

Abe