C-DRONE GUIDE · 21 SEPTEMBER 2026
Reblochon AOP and drones: mapping alpine-pasture biomass after the 2026 drought, price
Granted a French appellation d'origine contrôlée as early as 1958 and a European appellation d'origine protégée in 1996, Reblochon is produced exclusively in the mountains of Haute-Savoie and the Val d'Arly valley in Savoie, by around 620 dairy farms overseen by the Syndicat interprofessionnel du Reblochon (SIR), based in Thônes. The specification caps stocking density at 1.5 livestock units per hectare of usable farmland and requires cows' feed to come almost entirely from forage grown within the zone. The summer 2026 drought put that last point under strain: three orders published in the Official Journal on 1 September 2026 temporarily relaxed the rules for Reblochon, Cantal and Fourme d'Ambert, cutting the minimum summer grazing period to 120 days (against 150 in a normal year) and lowering to 75% the share of forage that must come from the geographic area (against 100%). Against that backdrop, drone-based biomass mapping of alpine pasture documents one precise thing: where usable grass still stands, alpage by alpage. Here is what it brings, and what it cannot settle.
Published on 21 September 2026, reviewed on 21 September 2026 — regulations in force as of September 2026.
Reblochon AOP: an alpine-pasture sector under derogation in 2026
Reblochon owes its name to an old practice of « reblocher » — a discreet second milking carried out as early as the 13th century to dodge a tax calculated on the first milk. Granted a French appellation d'origine contrôlée on 7 August 1958, then a European appellation d'origine protégée in 1996, it can only be produced within a defined zone: the mountains of Haute-Savoie and the Val d'Arly valley, straddling Savoie. The sector today brings together around 620 dairy farms, overseen by the Syndicat interprofessionnel du Reblochon (SIR), headquartered in Thônes. The specification caps stocking density at 1.5 livestock units per hectare of usable farmland, and grants a 50% volume bonus to farms operating on two distinct sites within the same year — a valley farm and an alpine-pasture farm — thereby recognising summer transhumance as an integral part of the system.
Summer 2026 put that system under strain. A lack of rain dried out pastures earlier and more severely than usual, threatening two central obligations of the specification: the minimum grazing period and the share of forage that must come from the zone. Three orders published in the Official Journal on 1 September 2026 temporarily relaxed the rules for Reblochon, as well as for Cantal and Fourme d'Ambert: the minimum summer grazing period drops to 120 days instead of 150, and the share of the zone's forage in cows' base ration falls to 75% instead of 100%. A derogation that gives farmers more room to manoeuvre, but does not remove the need to know, alpage by alpage, where usable grass still stands.
What drone biomass mapping documents on an alpine pasture
The principle behind drone biomass mapping is already covered in our guide on grassland biomass and grass-height estimation by drone: a photogrammetric height model or vegetation indices from a multispectral camera, calibrated against a few reference cut-and-weigh samples. On an alpine pasture, that principle runs into much sharper relief than on flat land — slopes, ledges, cast shadows — which makes the spatial variability of grass growth even more pronounced than on a valley meadow.
A German team led by Anne Schucknecht, Bumsuk Seo, Alexander Krämer, Sarah Asam, Clement Atzberger and Ralf Kiese published a 2022 study in the journal Biogeosciences dealing directly with pre-Alpine grasslands, comparable in relief and vegetation to Savoie's alpine pastures: comparing two low-cost drone-borne multispectral sensors (Parrot Sequoia and MicaSense RedEdge-M) and several statistical models, the authors estimated both available dry biomass and plant nitrogen concentration — an indicator directly linked to forage nutritive value (see the study on Google Scholar). Applied to an alpine pasture in the Val d'Arly or the mountains of Haute-Savoie, the same principle can pinpoint, sector by sector, where grass remains plentiful enough to justify keeping the herd there, and where it has thinned to the point that moving the herd is needed — a reading particularly useful in a summer where every extra grazing day counts toward the 120-day threshold. Pairing this survey with a thermal herd headcount also checks, in the same pass, that the actual stocking density stays consistent with the available grass area and with the specification's 1.5 LU/ha cap.
The honesty clause: a biomass map proves neither eligibility nor forage quality
The honesty clause. However precise it is, a biomass map does not settle the central question raised by the 2026 derogation: it does not count days. Eligibility for the relaxed 120-day grazing threshold rests on a declarative record — alpine-pasture entry and exit dates logged in the herd's grazing register, checked by the SIR and the INAO — not on an aerial image, however often repeated. A drone can document that grass was available on a given date in a given sector; it does not replace the register attesting that the herd actually grazed there for the required number of days.
Nor does the map say much about the forage's actual nutritive value: the Schucknecht et al. study itself makes the point — drone-estimated nitrogen concentration remains a statistical approximation, not a laboratory analysis. On a drought-stressed meadow, visually abundant grass can still be poor in energy value — only a laboratory forage analysis settles that question, one that matters for adjusting the herd's supplementary feed. Finally, the derogation allows up to 25% of forage from outside the zone: mapping a farm's own alpine pasture obviously says nothing about the origin or composition of that purchased forage, whose traceability remains a separate declarative obligation, checked independently by the SIR.
Who commissions this service, and 2026 prices
Demand comes from the Syndicat interprofessionnel du Reblochon, the sector's cheese-making cooperatives, the chambers of agriculture of Haute-Savoie and Savoie, and the groupements pastoraux that jointly manage numerous alpine pastures. The Alpine massif's airspace imposes its own constraints: relief that degrades GPS coverage, proximity to restricted zones around the Mont-Blanc massif, and mountain aerodromes and altiports — the Géoportail drone zone map remains the first reflex before any campaign, and our regional guide on drone missions in Auvergne-Rhône-Alpes covers the region's whole airspace picture.
Ranges observed in France in 2026, excluding VAT:
| Service | Observed price (excl. VAT) |
| Biomass mapping of one alpine pasture (up to 15 hectares, access and relief factored in) | €350 to €600 |
| Additional pass per extra 10 hectare block | €120 to €200 |
| Adding a thermal herd headcount to the same flight | €90 to €150 |
| Seasonal monitoring (several passes over the summer grazing period) | a declining package, often €250 to €450 per pass |
These figures cover the flight and delivery of a usable map, but neither the pasture's declarative register nor a laboratory forage analysis. A single groupement pastoral managing several neighbouring alpine pastures noticeably cuts the cost per hectare by pooling the drone operator's travel. Request a quote stating the number of alpine pastures, their area and the summer grazing period targeted.