---
title: what agroforestry does for the field beside it
canonical_url: https://ensurance.app/guide/what-agroforestry-does-for-the-field-beside-it
markdown_url: https://ensurance.app/guide/what-agroforestry-does-for-the-field-beside-it.md
subtitle: the belt that grows nothing pays the field that does
category: ecosystem-services
---

# what agroforestry does for the field beside it

*the belt that grows nothing pays the field that does*

**Agroforestry** is growing trees on purpose with crops or livestock: windbreaks and shelterbelts, hedgerows, alley cropping, silvopasture, riparian buffers, shade over a crop. Some of its benefits grow on the trees themselves, as nuts, fruit, timber, and fodder. Many of the largest land on ground the trees do not occupy. A windbreak grows no crop. The field beside it grows more. Shade trees moderate the air under them so the crop below suffers less. A hedgerow holds the pollinators and the predators that work the rows next to it. The trees are the stock. What they send across the line into the field is the flow. The yield is where the flow lands.

The belt is a living thing before it is a practice: a line of trees on what the framework calls [Cultivated & Developed](/natural-capital/stocks?from=guide) land, with the field edge as its boundary. It exists whether or not anyone counts the bushels beside it. [**Ensurance**](/?from=guide) is how the people on the far side of the line, the neighbor, the water users below, the buyer of the crop, can pay the belt. It is not the trees.

:::johnson
**the belt that grows nothing pays the field that does.** — The trees hold one strip. The shelter, shade, and pollinators they send out land on the rows beside them.

[see the flows farmland draws on →](/natural-capital/flows?from=guide)
:::

## the objection first

A farmer counts acres. A windbreak takes a strip of them out of crop, and a hedgerow takes the headland. On the day it is planted, that is lost ground, and the cost is real.

Agroforestry has a measure for what happens after. The **land equivalent ratio** compares a mixed system, trees and crop together, with the same land split into pure crop and pure trees. A ratio above 1 means the mixed system out-produces the split. The literature's word for that is **overyielding**. It measures the whole, not where the gain sits. In a windbreak the gain sits in the field beside the trees, and that crossing is what this series calls a spillover.

## agroforestry benefits, as measured

The numbers below are from the agroforestry and conservation literature, and each describes a flow crossing from the trees into the crop.

| the stock | the flow that leaves it | what the measurement found |
|---|---|---|
| A windbreak or shelterbelt | Shelter from wind; slower drying of soil and leaf | Adjacent crop yields raised by about 15% in semi-arid systems (USDA-ARS) |
| Shade trees over a crop | Moderated temperature under the canopy | Understory crop temperatures moderated by 2–4°C |
| Shade trees over a crop | Infiltration; slower water off the field | Runoff reduced by 20–50% |
| Natural habitat within about 1 km | Wild pollinators | Pollination services stabilized (Kremen et al. 2002, 2007); wild pollinators raised fruit set across 41 crop systems (Garibaldi et al. 2013) |

The first row is the plainest case in this series. A shelterbelt occupies a strip and grows nothing anyone sells. The field in its lee, for a distance that depends on the belt's height, yields more because the wind that would have dried and lodged the crop was slowed before it arrived. The belt's acres show a loss. The field's acres show the gain. They belong to the same farm, which is why farmers plant them.

The last row is on [wild bees and honey bees are not the same service](/guide/wild-bees-and-honey-bees-are-not-the-same-service?from=guide), which names the pollinators and what they need. This page does not repeat it.

## the flows, in the framework's words

Each of those crossings is one of the nineteen flows the framework tracks. Seven leave the trees here.

- **Food.** The yield itself, on the far side of the belt.
- **Pollination.** From the hedgerow and the patch, into the insect-pollinated crops within reach: fruit, nuts, melons, some oilseeds. Corn and wheat are wind-pollinated and do not need them.
- **Pest & Disease Control.** Predatory insects and birds that live in the trees and hunt in the rows. The evidence here is the most variable, as [does protecting one parcel help the land around it](/guide/does-protecting-one-parcel-help-the-land-around-it?from=guide) sets out: a patch can host the pest as well as the predator.
- **Healthy Soils.** Litter, roots, and infiltration that keep the soil on the slope and the water in it.
- **Climate Stability**, at the field scale. The 2–4°C under the shade tree and the slower drying in the belt's lee.
- **Clean Water** and **Erosion Control**, for whoever is below. The 20–50% less runoff under shade trees does not stop at the field edge either. It arrives at the creek as water that carried less soil.

## who is on the far side of the line

The farmer's own field is the first receiver, and the reason the practice exists. The far side of the line does not stop there.

| who receives the flow | which flow | where it is counted |
|---|---|---|
| The farmer's own field | Shelter, shade, pollinators, predators, held soil | Their yield |
| The neighbor's field, within the belt's lee or the pollinators' reach | Shelter, pollinators | The neighbor's yield |
| The creek, and whoever draws from it below | Less runoff, less sediment | A treatment budget, a reservoir's life, a fishery |
| The buyer of the crop | Part of the crop they contract for | Their supply, and any insetting claim they report |

The second row is where the farm's own accounting stops. A hedgerow's pollinators do not read the property line. A belt's lee crosses it. The neighbor's yield can rise, and nobody sends the planter a bill.

## where the value lands

On the farm that planted them, the gain shows up in the field they shelter, and the farm can see it. Everything that crosses the property line is paid for somewhere else: in the neighbor's yield, in the water treatment plant's budget, in the reliability a buyer enjoys without knowing why. The belt that produced the flow is, on most ledgers but the planter's, a strip of unproductive ground.

Some of it is already paid. Public conservation programs share the cost of planting windbreaks and buffers, and some pay rent on buffer strips for a contract term. Some food companies fund hedgerows in their supply sheds, which [insetting is not an offset](/guide/insetting-is-not-an-offset?from=guide) takes apart. Those are partial wrappers, and they work. They pay for the practice for a while. None of them pays the belt for what it sends next door for as long as it stands.

This is the same shape the reserve and the retained trees showed in the earlier posts. The stock stays put. The flow lands where it can be counted, and it is paid for there, to whoever is standing on it. [What is a keystone parcel](/guide/what-is-a-keystone-parcel?from=guide) is about the patches that carry the most for others; a farm hedgerow is one of its examples.

## the honest part

The 15 percent figure is for semi-arid systems, where wind and drying are the limiting factors, and it is measured on the sheltered crop, not net of the strip the belt takes. Whether the whole field comes out ahead depends on the crop, the belt, and the years it takes to grow. In wetter country the yield gain is usually smaller, and the case rests more on soil, water, and habitat. Right beside the belt, roots and shade compete with the crop, so the first rows can yield less; the gain comes further out in the lee. The shade figure moderates a crop that wants moderating; a crop that wants full sun loses under a tree. Pest control from a patch is the least predictable of these flows, and the patch can go the other way. And a belt takes years to reach the height that gives the lee its reach, so the loss comes first and the gain comes later. None of that changes where the gain lands.

## frequently asked questions

### what are the benefits of agroforestry?

Trees on farmland shelter crops from wind, moderate temperatures under shade, hold soil and water, and house the pollinators and predators that work the fields beside them. Measured effects include adjacent yields raised by about 15% in semi-arid systems behind windbreaks, 2–4°C of moderation under shade trees, and 20–50% less runoff where shade trees cover the crop.

### what is overyielding?

Overyielding is when trees and crops grown together produce more than the same land would produce split into pure trees and pure crop. It is measured by the land equivalent ratio; a ratio above 1 means the mixed system wins.

### does a windbreak increase crop yield?

In semi-arid systems, yes: adjacent yields rose by about 15% in the USDA-ARS literature, over a distance that scales with the belt's height. The belt itself grows no crop; the gain shows up in the field beside it.

### who benefits from a hedgerow besides the farmer who planted it?

Any neighbor within the pollinators' reach or the belt's lee, and whoever draws water from the creek below. They receive the flow without paying the trees for it.

## next

The next case moves into the city, where the stock is a park and the flow lands on a sale price: [do parks increase property values](/guide/do-parks-increase-property-values?from=guide).

If you farm with trees and can name the neighbor or the creek that depends on them, [landowners](/solutions/landowners?from=guide&topic=flows-across) shows what we coordinate for working land, from easements that keep it in agriculture to certificates tied to the natural assets on it, and you can [tell us which](/contact?from=guide&topic=flows-across).

## sources

USDA Agricultural Research Service, windbreak and shelterbelt research — adjacent crop yields raised by about 15% in semi-arid systems.

Agroforestry literature on shade-tree systems and overyielding — understory crop temperatures moderated 2–4°C; runoff reduced 20–50%; overyielding measured as a land equivalent ratio above 1.

Kremen, C. et al. 2002, *PNAS*; Kremen, C. et al. 2007, *Ecology Letters*. — Natural habitat within about 1 km stabilizes pollination.

[Garibaldi, L.A. et al. 2013. Wild pollinators enhance fruit set of crops regardless of honey bee abundance. *Science*.](https://doi.org/10.1126/science.1230200) — 41 crop systems.

## the series

1. [what is a spillover effect in nature](/guide/what-is-a-spillover-effect-in-nature?from=guide)
2. [do marine protected areas help fisheries](/guide/do-marine-protected-areas-help-fisheries?from=guide)
3. [what retention forestry actually does](/guide/what-retention-forestry-actually-does?from=guide)
4. [what agroforestry does for the field beside it](/guide/what-agroforestry-does-for-the-field-beside-it?from=guide)
5. [do parks increase property values](/guide/do-parks-increase-property-values?from=guide)
6. [what a positive externality is](/guide/what-a-positive-externality-is?from=guide)