C-DRONE GUIDE · 17 JULY 2026
Forestry Drones: Inventory, Mapping and Health Monitoring
France has 17.6 million hectares of forest, three-quarters of it privately owned and often split into small, hard-to-reach plots: inventorying a stand, quantifying storm damage or monitoring a forest's health remains, for many owners and forest managers, a heavy field burden. A drone fitted with a multispectral camera or a LiDAR sensor changes part of the equation: stem counts, canopy height, storm-damage mapping in a handful of flights instead of days of walking. Here is what the technology can really do, what it does not replace, and what it costs in 2026.
Published on 17 July 2026, reviewed on 18 July 2026 — regulations in force as of July 2026.
Why French forests need an aerial eye
According to the IGN's 2025 national forest inventory, forest covers 32% of mainland France, and the area keeps expanding every year. But that scale hides considerable fragmentation: in western France — Pays de la Loire, Nouvelle-Aquitaine, Brittany — more than 90% of the forest is privately owned, often in plots of a few hectares, with no vehicle track and dense undergrowth that makes walking slow and visibility close to nil beyond a few metres.
For an owner, a forest expert or a municipal woodland manager, that raises a very concrete problem: how do you inventory a stand, estimate standing timber volume, or simply know where a plot starts and ends, without spending weeks on it? After a storm, the question becomes urgent: quantifying windthrow to organise salvage logging and limit health risks (insects breeding in downed timber) cannot wait for an exhaustive ground walkthrough. That context — large area, difficult access, fragmentation, post-disaster urgency — is what opened the door to drones in the timber sector.
What a forestry drone actually measures: photo, multispectral, LiDAR
Three sensor types complement each other in forestry. Standard photography, processed through photogrammetry, produces an orthophoto and a surface model: canopy gaps, trees downed by storms, tracks, plot boundaries. But it measures the visible surface of the canopy, not the ground beneath it — a point covered on our drone surveying and photogrammetry page.
The multispectral camera (NDVI, NDRE) goes further: it picks up water stress and a drop in vigour across a stand before either is visible to the naked eye, on the same principle as vine-vigour monitoring described in our guide to mapping vine vigour by drone. LiDAR, in turn, sends out laser pulses that partially penetrate the canopy: some echoes return from the ground, reconstructing a terrain model beneath the canopy, measuring actual tree height and estimating stand density — what photogrammetry alone cannot do in wooded terrain.
One point should not be oversold: early detection of bark beetle outbreaks (the insect behind spruce dieback) by remote sensing, drones included, still runs into real limits. The available research confirms it: neither satellites, drones, nor aircraft-mounted cameras can today reliably spot infested trees early enough to act before the outbreak spreads; ground control — patrols, pheromone traps — remains irreplaceable. Where a drone excels is mapping damage that is already visible (browning crowns, dead trees) once an outbreak has been confirmed.
How a mission unfolds for an owner or forest expert
The mission almost always starts with a conversation with the owner or manager — forest expert, cooperative, or the French national forestry office for public woodland — about the goal: a full inventory, a targeted health diagnosis, windthrow volume assessment, or monitoring over time. The pilot then checks access to the site (tracks, permission to use private paths) and coordinates the time slot with the owner, particularly during hunting season, when the presence of outsiders in the woods needs to be flagged for everyone's safety.
The flight itself is planned as an automated grid, at a height that depends on the sensor: lower for fine multispectral detail, higher for LiDAR covering a large area in a single flight. On a stand of several dozen hectares, the day's flying is often followed by a second pass a few weeks later to confirm a change (an outbreak spreading, a felling operation progressing). Processing the data then takes several days: reconstructing the point cloud, computing heights and volumes, cross-referencing with the multispectral data. The final deliverable — orthomosaic, digital terrain model, stem count, vigour or damage map — is handed to the owner and, where relevant, their forest expert for the silvicultural interpretation: the drone supplies the data, the forest expert or forestry-office manager makes the diagnosis and the prescription.
What a forestry drone mission costs in 2026
Prices vary considerably with the sensor used and the area covered — LiDAR remains noticeably more expensive than standard photogrammetry, given the sensor and point-cloud processing involved. Ranges observed in France in 2026:
| Mission | Observed price (excl. VAT) |
|---|---|
| One-off small-plot diagnosis (photo + orthophoto, up to 5 ha) | €350 to €550 |
| Multispectral vigour mapping (up to 20 ha, analysis report) | €700 to €1,100 |
| Forestry LiDAR survey (height, density, under-canopy terrain model, up to 50 ha) | €1,400 to €2,200 |
| Post-storm survey (windthrow mapping and indicative volume, urgent) | €600 to €1,000 |
| Multi-year campaign on a large estate (grouped ownership, forestry office) | on quotation |
What moves the quote: the sensor (LiDAR versus RGB/multispectral), canopy density (a dense high forest needs more laser power and post-processing than an open stand), how remote the site is, and the number of passes needed for monitoring over time. For a small property, pooling the flight with neighbouring plots or ordering through a forest-owners' association often brings the per-flight cost down.
Regulation: flying over private forest, category and precautions
Flying over private forest does not require the owner's permission as far as airspace goes — nobody owns it — but accessing the land to take off or use the tracks still needs their agreement, just like any professional work on private property. Most forestry missions fall under the open category, subcategory A3 (far from any person, drones up to 25 kg): forest tracts are by nature remote from inhabited areas, which simplifies operations compared with a flight in a town. A specific-category authorisation (STS-01/STS-02) only becomes necessary for large public forest tracts flown BVLOS, or for LiDAR drones exceeding the open category's weight thresholds.
Before every flight, the pilot checks the Géoportail drone map — forest tracts regularly overlap military low-altitude flight zones or sensitive natural areas, which impose time slots or restrictions; our guide to reading the Géoportail drone zone map covers this check in detail. Flight height stays capped at 120 metres without authorisation, and the operator must be registered on AlphaTango with an FRA number and carry aerial liability insurance under Regulation (EC) No 785/2004. One point to watch in summer: during periods of high wildfire risk, some prefectural orders restrict activity in forests, drones included.
Frequently asked questions about forestry drones
Can a drone detect every bark beetle outbreak before it spreads? No, and be wary of any provider claiming otherwise without qualification: the available research shows that remote sensing, drones included, does not reliably spot infestations early enough. A drone remains very useful for mapping how far an outbreak has spread once the first symptoms are confirmed on the ground.
LiDAR or multispectral: how do you choose? LiDAR is the right tool for measuring stand structure beneath the canopy — height, density, timber volume, natural terrain in closed forest. Multispectral answers a different question: tree vigour and stress. For a full inventory, the two sensors are often combined in a single flight.
How accurate is a drone-estimated timber volume? On a homogeneous stand well sampled on the ground as a complement, LiDAR volume estimates reach an accuracy comparable to traditional inventory methods, with the advantage of covering the whole plot rather than isolated sample points. The report should always state its method and its margin of uncertainty.
Do you need the forestry office's agreement to fly over state-owned forest? Yes: beyond the standard flight authorisation, an agreement with the national forestry office is required to work on public forest, whether for an inventory, health monitoring or filming.