C‑DRONE
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C-DRONE GUIDE · 28 JULY 2026

Farm hedgerow mapping by drone: length, CAP subsidy, price

A poorly measured hedgerow can be costly: under-declaring its length cuts into a farm's subsidy payments, over-declaring it exposes the holding to an inspection and a conditionality penalty. Since the 2023-2027 CAP reform, hedges, coppices and ponds are landscape features protected under BCAE 8: they cannot be grubbed up without compensation, cannot be cut between 16 March and 15 August, and some holdings must devote a share of their arable land to agroecological infrastructure that includes hedges. At the same time, the hedgerow pact launched in late 2023 targets a net gain of 50,000 km of hedges by 2030, while France currently loses around 20,000 km a year. Between a maintenance obligation and a valuation opportunity, a reliable, dated hedge inventory becomes a management document in its own right. Here is what drone mapping brings, how it unfolds, and prices observed in 2026.

Published on 28 July 2026, reviewed on 5 August 2026 — regulations in force as of August 2026.

BCAE 8, a constraint measured to the metre

Since 2023, CAP subsidy conditionality has required farmers to maintain declared landscape features — hedges under ten metres wide, coppices, ponds under half a hectare — and bans grubbing them up without compensation or cutting them during the nesting period, from 16 March to 15 August. Holdings with more than ten hectares of arable land that are not mostly under grass must also devote at least 4% of their arable area to agroecological infrastructure — hedges, coppices, fallow, grassed strips — or 7% when catch crops and nitrogen-fixing crops are included.

The length declared in the land parcel register is the reference for any inspection: a significant gap between the real and the declared length, in either direction, exposes the holding to a subsidy correction. Many farms still work from an inherited length, never re-checked since the initial declaration, even though hedges change over time: dieback, an unreported partial removal, regrowth after planting. It is the same periodic-update need as the business park inventory run by local authorities, applied to farmland instead.

What the drone measures: length, height, continuity

A photogrammetric flight over the holding produces an orthophoto and a canopy height model: the length of each hedge can be measured directly from these vectors, without ground surveying plot by plot. The height model also tells a continuous, well-stocked hedge apart from one with gaps or degraded sections — information that satellite remote sensing, limited in resolution, struggles to deliver at farm scale. A study by Marcin Smigaj and Rachel Gaulton published in 2021 in Remote Sensing in Ecology and Conservation demonstrated the drone's ability to capture hedge structure and flowering abundance with a precision useful for field inventories (see the study on Google Scholar).

A drone pass also settles points that are often disputed: a hedge's actual width (the ten-metre BCAE 8 threshold), continuity across a field entrance or access track, and telling a hedge apart from a row of isolated trees. On holdings already using precision agriculture, the same campaign usually already serves other purposes — plot mapping, crop monitoring — which keeps the marginal cost of the hedge survey low.

The hedgerow pact: from a constraint to a valued project

The hedgerow pact, presented by the Ministry of Agriculture in late September 2023, is not limited to protecting the existing network: it targets a net gain of 50,000 kilometres of hedges across France by 2030, with a dedicated budget exceeding €100 million from 2024, to reverse a trend that currently loses around 20,000 km a year. In practice, holdings that plant or replant hedges under this scheme have an interest in precisely documenting the starting state and tracking establishment — the same monitoring logic as forest replanting monitoring, applied to farmland hedges.

A dated survey also serves as evidence during an inspection: it establishes that a hedge existed on a given date, with a given width and height, and documents any natural degradation (dieback, disease) that sets it apart from an unreported deliberate removal.

Method and deliverables

The flight is planned outside the nesting period so as not to disturb wildlife that depends on hedgerows, and preferably in winter or early spring: without dense foliage, the network's structure — trunks, gaps, actual width — reads more clearly, while an additional summer pass assesses vigour and flowering, useful for holdings valuing the ecological role of their hedges in an agri-environmental scheme application. The flight is flown under the open category most of the time, over open rural land, subject to checking the aeronautical chart for plots near an agricultural aerodrome or a military zone.

Deliverables include a vectorised length broken down by hedge section, usable directly in CAP declaration software or handed to the local chamber of agriculture's advisor, a dated orthophoto, and optionally a canopy height model to give an objective view of the hedge's condition. On holdings engaged in an ecological compensation scheme or an agri-environmental contract, the same dataset serves as the baseline for multi-year monitoring.

Prices observed in 2026

Ranges observed in 2026 (excl. VAT), for a farm holding rather than a full local authority campaign:

Pooling costs across a farming group or cooperative significantly lowers the per-holding cost, in the same way a chamber of agriculture might commission one campaign for several member farms in the same area. Request a quote stating the holding's area, approximate hedge length and intended use (CAP declaration, planting project, agri-environmental scheme).

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