C‑DRONE
Top-down orthophoto-style view of farmland parcels captured by drone

C-DRONE GUIDE · 2 AUGUST 2026

Log pile volume by drone: measuring a roundwood stock at a sawmill or in the forest, method and price

A sawmill's timber yard or a forest roadside landing accumulates tens, sometimes hundreds of cubic metres of stacked logs — a volume that directly determines the price paid to the supplier, the stock's inventory value or the amount of an insurance payout after a loss. The reference method — measuring each log with a tape and applying a cubing table — stays reliable piece by piece but becomes endless and labour-intensive once a whole pile is involved. Drone photogrammetry changes the scale: a flight of a few minutes around the pile is enough to reconstruct a 3D model whose volume is computed directly. Here is the method, its limits compared with unit cubing, the applicable regulatory framework and the prices charged in 2026.

Published on 2 August 2026, reviewed on 6 August 2026 — regulations in force as of August 2026.

Traditional cubing: accurate piece by piece, a source of disputes at pile scale

Cubing a single log remains a well-mastered gesture: diameter measured with a tape or forestry calliper at mid-length, length recorded, then a cubing table (Grandval-Deswarte, Schaeffer) or a geometric formula converts these measurements into commercial volume. This is the method required for selling high-value shaped timber — an oak or wild cherry log destined for veneer is still cubed piece by piece, on value.

The problem appears at stock scale: cubing the hundreds of logs in a sawmill's timber yard or a forest roadside landing one by one keeps an operator busy for hours, sometimes days, with a cumulative error risk that grows with the number of pieces measured hastily. This gap between the volume declared by the supplier and the volume found on receipt is a recurring source of commercial disputes between forest operators, cooperatives and sawmills — every party has an interest in a fast, independent and traceable measurement of the whole pile.

Drone photogrammetry: a 3D model of the pile in a few minutes

The principle is the same as the one detailed in our guide to drone stockpile volume measurement at quarries, with a difference in nature that changes the calculation: an aggregate pile forms a continuous surface, whereas a pile of stacked round logs leaves gaps between the individual logs and under the bark. The drone flies over the pile on an orbital pattern or in parallel strips, capturing dozens of photos with heavy overlap; photogrammetry software (Pix4D, DroneDeploy, Metashape) reconstructs a dense point cloud and then a digital surface model, whose raw volume is computed by difference against a ground reference plane.

This raw volume does not directly match the volume of solid wood: a stacking coefficient (or void ratio) specific to round timber must be applied, depending on the logs' average diameter, whether they are debarked and how regularly they are stacked — a parameter first calibrated by comparison with a reference unit cubing, then reused for later measurements of the same type of wood. A study published in 2023 in the journal Remote Sensing by Đuka, Papa, Lovrinčević, Bumber, Poršinsky and Tomljanović, from the forestry faculty of the University of Zagreb, compared classic terrestrial cubing with drone-based photogrammetric measurement on oak logs: it concludes that the drone approach is viable as an alternative to terrestrial methods, with a clear speed advantage on a felling site (see the study on Google Scholar). To guarantee the model's absolute accuracy, an RTK or PPK drone remains recommended once the stock carries significant commercial value: our guide to RTK/PPK, when to require it covers this choice.

Regulatory framework and professional use cases

A forest roadside landing is most often far from any person and more than 150 m from residential areas: the flight then takes place in open-category subcategory A3, with no particular constraint beyond registering the operator on AlphaTango and checking restricted zones on the Géoportail map. A sawmill yard, by contrast, often sits next to buildings, moving handling equipment and staff: the flight then falls under subcategory A2, which requires the remote pilot to hold the matching certificate, or under a specific-category scenario if the site configuration demands it — our guide to the open versus specific drone category covers these thresholds.

Those requesting this type of mission are first forest operators, cooperatives and timber merchants, who want an objective sale or purchase volume without tying up a team for several days; sawmills, for a periodic inventory of their timber yard, useful for both cash management and reporting; and insurance experts, called on to value a stock loss after a fire or storm, a situation where measurement speed matters as much as reliability. Drone measurement complements the standing-stand inventory already covered by our guides to forestry management by drone and forest carbon inventory by LiDAR, applying this time to timber already felled and stored — a distinct link in the chain, from the crown to the sawmill yard.

Limits compared with unit cubing, and 2026 prices

The drone does not replace unit cubing of a high-value log intended for individual sale: it gives a global, reliable volume for a pile, not the individual valuation of an exceptional cherry or oak log, which is still measured with a tape. It also requires a pile that is clear and visible from the air — a landing under dense forest cover limits photogrammetric reconstruction — and a stacking coefficient calibrated for the type of wood involved, without which the computed solid volume loses reliability. It should also be distinguished from thermal monitoring of wood-chip stockpiles, which addresses a fire-safety issue on a processed product, different from the commercial cubing of raw logs.

Orders of magnitude observed in France in 2026 (excl. VAT):

Our guide to how much a drone service costs details the parameters that make these amounts vary. This service falls under our drone surveying and photogrammetry offering; request a quote stating the pile's area, the wood species and the logs' average diameter.

Frequently asked questions

Does the drone replace manual log cubing?

Not for a high-value log sold individually, which is still cubed with a tape. The drone, however, suits the overall measurement of a whole pile, where unit cubing would become too slow and costly — the two methods complement each other depending on the value and scale of the measurement.

What accuracy can be expected from a drone-based cubing?

With an RTK/PPK drone and a stacking coefficient properly calibrated for the type of wood measured, accuracy approaches that of a reference terrestrial cubing. Without prior calibration or precision positioning, the gap with the actual measurement can be significant.

How often should a timber stock be measured at a sawmill?

That depends on how fast the timber yard turns over: a monthly or quarterly check is enough for routine management monitoring, while a high-turnover sawmill or a strategic stock justifies more frequent visits, even weekly monitoring during periods of high activity.

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Put it into practice

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