What Is Agroforestry? Inside Bristol's Two-Acre Food Forest
This Summer’s drought has increased concerns about food security, with farmers struggling to make ends meet while producing food. While times may seem tricky, the solution doesn’t require new, advanced technology. Rather, the technologies already exist and have done for thousands of years. The answer? Trees.
At Generation Soil, we’ve been growing a two-acre food forest with 74 different trees. We’re part of an agroforestry movement, aiming to create more resilient food systems by harnessing the power of trees and shrubs.
Understanding Agroforestry
Since the advent of industrial agriculture, most farms have focused on producing yields, whether crops, dairy, or meat. However, agroecology goes beyond production. It aims to help sustain the natural landscape and biodiversity of a farming area.
Agroforestry is a practice within agroecology and involves having trees and shrubs in areas of crops and livestock, such as cows and sheep. These elements work together in a mutually beneficial way. Tree roots dramatically improve the structure of soil, increasing the movement of water, and helping crops survive and grow. Trees also provide shade and shelter for livestock (and humans!), improving welfare and consequently the production of dairy, wool and other animal goods.
In return, crops and animal manure feed nutrients back into the soil, which are used by trees and shrubs to support their growth. Crops also provide ground cover, reducing soil erosion, which is where the loss of top layers of soil are lost through natural forces like wind and rain. This protects the soil around trees, aiding their growth.
This dynamic relationship can have huge benefits for the environment. Together, trees and crops increase biodiversity by offering more habitats, foods, and shelters than either would alone. This combination may increase the biodiversity of farms up to 40% according to a research analysis, published in the Climate Resilience and Sustainability journal.
What Does Agroforestry Look Like?
Agroforestry doesn’t mean just randomly planting trees in a field with crops or livestock. Rather, farmers deliberately plant and place trees with certain spacing and arrangements.
Common layouts include:
Alley Cropping: Trees and shrubs occur in long, evenly spaced rows with wide lanes in between for regular farm crops like wheat, vegetables and squash
Windbreaks and shelterbelts: Rows of trees are planted specifically to block prevailing wind, usually along the exposed edge of a field; This reduces crop damage and soil erosion caused by wind
Silvopasture: Widely-spaced trees occur in grazing fields providing shade and shelter to the animals
Riparian buffers: Trees and shrubs occur along waterways, like rivers, streams and ditches; The roots help prevent soil erosion and filter animal waste and fertilizers from the soil before it reaches and pollutes the water
Food Forests: A system designing the structure of a forest, with different layers of vegetation that all provide a useful product
The Generation Soil Seven-Layer System
Our Generation Soil Market Garden is a living example of a Food Forest in Abbots Leigh, Bristol. We;re developing what’s known as a seven-layer agroforestry design, where plants are stacked vertically, instead of spread out in rows. This produces multiple types of crops in a small space.
Canopy: At the top sit the tallest plants in our system. Our apple and pear trees are still young, planted as part of the 74 trees that went in during our first year. They are a decade or more from full production, but they are already setting the structure of the site and beginning to shape the light levels for everything growing beneath them.
Lower canopy: Hazel sits below the fruit trees, shorter and more shade tolerant. We coppice hazel on rotation, which means cutting it back to the base every few years and letting it regrow. The cut material becomes woodchip for our composting and structural poles for building on site. Sea buckthorn also sits in this layer, fixing nitrogen into the soil and producing bright orange berries that are extraordinarily high in vitamin C.
Shrubs: Blackcurrant, gooseberry, jostaberry and Japanese wineberry are all establishing here. Soft fruit comes into production much faster than tree fruit, so this is the layer we expect to start harvesting from first. Blackcurrants in particular should give us a meaningful crop within three or four years of planting.
Herbaceous layer: This is where the perennial herbs and larger non-woody plants sit. Comfrey is the workhorse. We plant it in rings around our young trees, where its deep roots draw minerals up from the subsoil. We then cut it back several times a season and drop the leaves as mulch, feeding the trees directly. Lovage, sorrel, angelica and fennel are also going in here, all of them perennial, all of them edible.
Ground cover: A layer of low, spreading plants that stay close to the soil surface rather than growing upward. Wild strawberry, creeping thyme and clover do this work for us. Their job is as much about protecting the soil as producing food. Bare soil bakes hard and dry in a summer like this one, and a living cover keeps it cooler, holds moisture, and stops erosion when the autumn rain arrives.
Vines and climbers: Hardy kiwi and honeysuckle will climb through the system, using the vertical space that would otherwise go unused. Hardy kiwi is a smaller, smooth-skinned relative of the fruit most people know, and it is hardy in the British climate.
Root layer: At the bottom sit the plants that develop underground. Perennial vegetables like skirret, Jerusalem artichoke and walking onion produce year after year without replanting, which suits a site like ours where we are not there every day. Below them, and invisible, is the mycorrhizal network. Fungal threads connect plant roots across the site, moving water and nutrients between them. It is the layer we understand least and depend on most.
Why Layered Agroforestry Systems Work
The point of stacking it this way isn't just neatness. Each layer occupies a different slice of space and root depth, so the plants aren't competing for the same light, water, or nutrients.
It also changes how the site functions as a whole. A flat monoculture bed offers one kind of habitat and one harvest, once a year. A seven-layer system offers several: flowering trees for pollinators in spring, fruiting shrubs through summer, and ground cover holding the soil together year-round.
And because the system isn't relying on one crop alone, it's naturally more resilient. If blight hits the apples one year, the hazel, currants, and gooseberries are still producing. This is a kind of built-in redundancy that’s hard to get from a single-crop field.
Agroforests may not match the raw yield-per-hectare of a monoculture farm, but they make up for it in diversity. Diversity matters, not just for the wildlife it supports, but for our own health too.
If food forests become a bigger part of how we source our food, we'd have access to a much wider range of fruits and vegetables. That variety is essential for a strong, healthy gut microbiome. Moreover, in food forests, the soil becomes much denser with minerals than generic farms, helping plants make more anti-oxidants and other useful compounds that our bodies need to protect against diseases and maintain overall health.
The Future of Agroforestry and Next Steps in Bristol
"The food forest is young. All of what we have planted is less than two years old, and a food forest measures its progress in decades rather than seasons. Right now the site is still exposed, establishing, and asking a lot from us in a drought year like this one.
The next stage is shelter. We are planting a dense native shelter belt this winter along the most exposed edge of the site, using fast establishing species like Italian alder, willow and hawthorn. Planted tightly, these will close canopy within a few years and create the cooler, more humid conditions that everything else needs to thrive. Shelter is the thing a mature forest provides for itself, and what a young one cannot.
Alongside that, we are regenerating the soil. Last winter we sowed field beans and mustard as green manure across the growing areas, and this spring we chopped and dropped most of that growth straight back onto the ground, feeding the soil. Some of it we did harvest, though. Broad beans have become miso, and mustard seed has become mustard. Both are experiments in whether the early years of soil regeneration can pay for themselves, turning a soil-building crop into something we can sell while the perennial system is still finding its feet.
Water resilience is the other piece. Rainwater harvesting, better irrigation and deep mulching all help, but the real work is in the soil itself. Every tonne of compost we return to the ground increases how much water that ground can hold. This is the loop closing: food scraps from Bristol households, composted at our hub, returned to soil that then grows food.
This summer has taught us a lot about what actually works here. Our three sisters planting of sweetcorn, squash and beans has done well, with the three crops supporting each other in the way they have for centuries. Perennials like Jerusalem artichoke have shrugged off the drought pretty well too. As the summer draws to a close we will be reassessing all of it, working out which varieties have earned their place in the space.
We are also expanding what the site produces. A polytunnel is going up this autumn, which will give us propagation space for plants, seedlings and the beginnings of a growing kit offer. We are trialling heritage bean varieties for seed, and considering a textiles and dye garden to supply Bristol's sustainable fashion scene. Each of these is small on its own, but together we hope to demonstrate what two acres can do when it is not asked to grow one thing.
And we want people here. The site is a place to learn as much as a place to grow. We run workshops on soil, composting and growing, and as the food forest matures we want it to become somewhere Bristol can come and see what a different kind of food system actually looks like, standing up, in the ground, producing.
Our hope is straightforward. That in ten years this is a working, productive, shaded, biodiverse two acres that feeds, teaches, and inspires," says Alex Montgomery, Founder of Generation Soil
Beyond our market garden, farms around the world are starting to put agroforestry into practice. In the UK, farmers can now be paid to plant and maintain trees alongside crops and livestock, through the Sustainable Farming Incentive (SFI). The numbers are still small with only an estimated 3.3% of the UK's farmed area currently using agroforestry. But with these initiatives underway, this figure is likely to keep rising.
Be part of it
None of this works without the soil, and the soil starts in Bristol’s kitchens.
The Bristol Living Compost Project collects food scraps from homes and businesses across Bristol in clean, sealable buckets, ferments and composts them at our hub in Bedminster, and returns living compost to the people who made it. Members get compost back for their own gardens, allotments and balconies, and some of it comes here, to build the soil under these trees.
If you’d like your scraps to become soil, find the membership that fits your household. Plans start at £5 a month, and every twenty paying members fund a free place for someone who couldn’t otherwise join.
If you’d rather get your hands dirty, the food forest runs regular volunteer days, and there’s always something to do, whether that’s planting a shelter belt, cutting comfrey or putting a polytunnel up. No experience needed. Head to our Get Involved page to join the volunteer list, or come along to one of our workshops on soil, composting and growing.
Two acres is a start. What it becomes depends on who turns up.
Comments