Tree Intercropping

Food

Tree Intercropping

Rows of trees through the crop field. The oldest field boundary in the world, torn out in fifty years to make room for a bigger tractor.

🌱Seasons

The effect compounds within years. Put it in place and it keeps working.

Project Drawdown classifies this as Gradual.

Origins

The hedgerow is the most quietly catastrophic loss in the agricultural landscape of the twentieth century, and it happened within living memory.

Britain lost something on the order of half its hedgerows after the Second World War — hundreds of thousands of kilometres of them — grubbed out with government grants, because the new machines needed bigger fields and food security demanded maximum yield. Similar things happened across northern Europe and the American Midwest, where the shelterbelts planted in response to the Dust Bowl were later bulldozed once the memory of the dust faded and the tractors got wider.

Those hedges were not decoration. They were the field’s infrastructure. They held the soil down, sheltered the crop from the wind, gave the birds and the beetles somewhere to live — and the beetles ate the aphids, which meant the farmer sprayed less. They were the water management system, the pest control system, the fuel supply and the boundary marker, and they had been all of those things for a thousand years.

We removed them for a machine.

And it is worth saying plainly that the farmers who did it were not being reckless. They were being paid to do it, by governments that had watched a nation nearly starve during a war and had decided, understandably, that yield was the only thing that mattered. Every one of those hedges came out under an incentive. That is the pattern in almost every one of these pages, and it is why moralising at farmers is both cruel and useless.

What it actually is

Tree intercropping — alley cropping, shelterbelts, windbreaks, hedgerows — means running lines of trees or shrubs through or around cropland, and continuing to farm between them.

The mechanisms are several and they compound.

Wind. A shelterbelt reduces wind speed for a distance many times its own height, which cuts soil erosion, reduces crop moisture loss, and can measurably raise yields in the sheltered zone — sometimes enough to more than compensate for the land the trees occupy.

Water. Tree roots go far deeper than crop roots, pulling water and leached nutrients back up from below the reach of the annual crop and returning them to the surface in leaf litter. In an alley cropping system the trees are effectively a pump and a safety net.

Life. A hedge is a corridor. It is where the beneficial insects overwinter, where the birds nest, where the small mammals move between fragments. A landscape of bare fields is a landscape of islands, and hedgerows are the bridges.

Carbon. In woody biomass above ground and in deeper soil carbon below, on land that keeps producing food.

And a crop of their own. Timber, fruit, nuts, fodder, firewood. A row of walnuts through a wheat field is a pension growing between harvests.

The numbers

The land trade. Trees occupy some of the field — typically a modest percentage in an alley system. The question is whether the yield gain in the sheltered zone, plus the tree products, exceeds the yield lost to the rows. In many documented systems it does, and the metric agronomists use for this is the Land Equivalent Ratio: how much land a monoculture would need to produce what the combined system produces. Well-designed intercropping systems routinely score above 1, meaning the combination outperforms the separate parts.

The wind. A shelterbelt reduces wind speed over a distance of roughly ten to twenty times its height downwind. On an exposed prairie or a plain, that is not a marginal effect.

The pest control. Hedgerows harbour the predators of crop pests. The value of this ecosystem service is genuinely large and almost never appears on a balance sheet, which is precisely why the hedges were removed.

The scale of the loss. Britain grubbed out roughly half its hedgerows in the decades after the war. The American Midwest removed shelterbelts planted specifically in response to the Dust Bowl. The infrastructure was deliberately dismantled, at public expense, within a single lifetime.

The carbon. Modest per hectare compared with forest, but applied across the world’s cropland — which is an enormous area — and it does not take the land out of food production, which is the entire point.

Why it matters

Ask an old farmer about the hedge that used to run along the bottom field.

He will remember it. He will remember what was in it, and where the pheasants nested, and the tree his father used to say was the boundary with the next farm. He may well have taken it out himself, in 1974, with a grant, because the man from the ministry said the field was too small and the new machine could not turn in it.

There is a very particular grief in that, and it is not sentimental. It is the grief of having been told to do something that turned out to be wrong, by people who were confident, and of having to look at the consequence out of the kitchen window for the rest of your life.

This is why we think tree intercropping is one of the most emotionally available solutions on this list. It is not asking a farmer to change what he is. It is not asking him to stop growing wheat, or to feel guilty about his cattle, or to accept that his life’s work has been a mistake. It is asking him to put the hedge back.

And when he does, the birds come back within a couple of seasons, and the soil stops blowing off the top field in March, and the beetles come back, and he sprays a little less. He will not describe any of that as climate action. He will describe it as putting the farm right.

His grandfather planted that hedge. His grandson can plant it again. That is the whole of it.

What it actually takes

The machine, still. The reason the hedges came out has not gone away: modern equipment is enormous, and trees are in the way. Alley cropping has to be designed around the working width of real machinery or it will not be adopted, and designing it well is a genuine agronomic skill.

Establishment cost and delayed return. The same problem as every tree solution. Trees cost money now and pay in a decade. Cost-share for establishment is the intervention that works, and it is not expensive.

Competition, which is real. Trees compete with the crop for water and light in the rows immediately adjacent. In dry regions this can be significant. Species and spacing choice determines whether the trees are a shelter or a competitor, and getting it wrong is entirely possible.

Reversing the subsidy, again. Hedgerows were removed with public money. In parts of Europe they are now being replanted with public money. This is not hypocrisy; it is a correction, and it is worth being honest that the original policy was wrong rather than pretending it was somebody else’s idea.

Where it matters most

The Great Plains is where the shelterbelts were planted in response to the Dust Bowl and where many were later removed. It is also where the wind is, and where the soil is going, and where they are most needed again.

The Corn Belt is the largest opportunity by area: an enormous, almost treeless expanse of the world’s best cropland, losing soil and leaching nitrogen into the Mississippi. Rows of trees would hold both.

The English Midlands and Ireland are where the hedgerow loss was most complete and best documented, and where replanting is now supported by policy.

The Sahel is the most inspiring case on Earth. Farmer-managed natural regeneration — simply protecting the trees that resprout naturally in fields rather than clearing them — has greened millions of hectares across Niger and Burkina Faso, restored soil, raised yields and increased household resilience, at almost no cost. It was not planted. It was allowed.

The Loess Plateau is the largest deliberate landscape restoration in history, and tree lines through cropland were central to it.

How to tell it’s being done well

Is the species right for the site? A tree that competes hard for water in a dry region will cost yield. A well-chosen deep-rooted species will not. This is the difference between a system that works and a system that gets removed again in ten years.

Does the design fit the machinery? If it does not, it will be torn out. This is not a moral failing; it is a design failure.

Do the trees pay? Timber, nuts, fruit, fodder. Trees with a market survive. Trees planted purely for carbon get removed the moment the payment stops.

Is anyone protecting natural regeneration? In much of Africa the cheapest and best intervention is not planting anything. It is not cutting the saplings that come up on their own.

What you can do

Anyone

  • Look at the fields near you. If they are bare from edge to edge, that is a recent condition and it was created by policy within living memory.
  • Hedgerows are habitat corridors. Local campaigns to protect and replant them are unusually winnable.

Farmers

  • Start with the windward edge and the erosion-prone slope. That is where the return is fastest and most visible.
  • Choose trees that pay you: timber, nuts, fruit, fodder. A tree with a market is a tree that stays.
  • Design around your machinery, not against it. A system that fights the combine loses.

Policymakers

  • Cost-share establishment. It is a small, well-defined subsidy with a very long payoff.
  • Support farmer-managed natural regeneration where it applies. In the Sahel it has greened millions of hectares for almost nothing.
  • And acknowledge that hedgerow removal was publicly funded. Correcting a policy error is easier when you name it.

Business and investors

  • Agroforestry timber and nut systems on existing cropland are a real and underfunded asset class.
  • Supply chains that depend on prairie soil should be interested in whether that soil is still there in fifty years. Currently it is blowing away.

Who is working on this

We are researching which organizations in our directory of 8,493 actively work on this solution, and we only list an organization once we have verified it. That research is ongoing. In the meantime, search the directory yourself:

Search the directory for “Tree Intercropping” →

Questions

What is tree intercropping?

Running lines of trees or shrubs through or around cropland and continuing to farm between them: alley cropping, shelterbelts, windbreaks, hedgerows. The trees provide shelter, deep-root water and nutrient recycling, habitat for beneficial insects and birds, carbon storage, and often a crop of their own in timber, nuts or fruit.

Doesn't planting trees in a field reduce the crop?

It takes some land, yes, but the sheltered zone frequently yields more, and the trees produce their own harvest. Agronomists measure this with the Land Equivalent Ratio, and well-designed intercropping systems routinely score above 1, meaning the combined system outproduces the separate parts on the same land.

What happened to the hedgerows?

They were removed, mostly with public money, in the decades after the Second World War, because larger machinery needed larger fields and food security policy prioritised maximum yield. Britain lost roughly half its hedgerows. The American Midwest removed shelterbelts that had been planted specifically in response to the Dust Bowl.

How much does a windbreak actually help?

A shelterbelt reduces wind speed for roughly ten to twenty times its own height downwind. On an exposed plain that substantially reduces soil erosion and crop moisture loss, and can raise yields in the sheltered zone enough to more than pay for the land the trees occupy.

What is farmer-managed natural regeneration?

Protecting the tree seedlings that resprout naturally from existing root systems in farmers' fields, rather than clearing them. Across Niger and Burkina Faso this has greened millions of hectares, restored soil and raised yields, at almost no cost. Nothing was planted. The trees were simply allowed to grow.

What is the main barrier?

The same one that removed the hedges: machinery, and the delayed return. Modern equipment is enormous and trees are in the way, so intercropping must be designed around real working widths. And trees cost money now and pay in a decade, which is a cash-flow problem with a well-understood cash-flow solution.

Sources

The solution taxonomy follows the framework popularised by Project Drawdown. The analysis above is our own; for their carbon modeling and rankings, visit them directly.