Products · VTOL Fixed-Wing

VTOL Configuration for Forestry Resource Survey

Forestry survey has one dominant variable: canopy. It changes both the terrain model you can derive and the visibility of what you are trying to measure.

5 of 10Method note

Overview

Decide whether you need bare-earth terrain or a canopy surface — they are different products from the same flight.
Dense canopy means the visible surface is the canopy, so area and height metrics describe trees, not ground.
Fly in leaf-off season if the objective needs ground visibility, and record the season with the data.
Report accuracies are relative to ground control density; state the control spacing alongside any accuracy figure.

Forestry survey is a sampling problem before it is a flight problem

The mistake most often made in forestry survey is to treat it as a mapping task and fly the whole area at a uniform specification. Forested terrain is large, often remote, and frequently of uneven commercial value; uniform high-resolution acquisition over all of it is expensive in a way that rarely pays back. The correct framing is a sampling problem: what needs to be measured everywhere, what needs to be measured on a sample, and what can be inferred from the sample.

That three-tier structure drives the whole configuration. Canopy height and extent are usually needed across the whole area and can be acquired at moderate resolution. Species composition, health indicators and understorey condition are usually needed on representative plots and require higher resolution or a different sensor. Volume and yield estimates are then built from the plot data extrapolated across the area using the wall-to-wall canopy layer.

This matters because it changes what the aircraft has to do. Wall-to-wall moderate coverage is exactly what a VTOL fixed-wing does efficiently; plot-level detailed acquisition is a short-duration, high-quality task that may be better served by a multirotor or by a slower, lower pass. Mixing both into one sortie profile usually compromises both.

Sensor selection against the forest structure

A visible-light camera delivers canopy surface information: extent, colour, texture, gaps and, through photogrammetric reconstruction, a canopy height model. That is sufficient for a surprising amount of forestry work and it is the cheapest data per hectare. Its limitation is structural — it sees the top of the canopy and infers what is below.

Where the deliverable concerns terrain beneath the canopy, or stem-level structure, a LiDAR payload becomes relevant because it penetrates gaps and returns multiple elevations per pulse. The trade is mass, power, cost per hectare, and a calibration and processing workload substantially heavier than photogrammetry. Decide on the deliverable: if you need a ground surface under closed canopy, camera photogrammetry cannot give it to you at any resolution.

Multispectral data adds information on vegetation vigour and species discrimination, which is valuable for health assessment and, in some contexts, for species classification. It is not a substitute for either of the above; it answers a different question. Our multispectral integration assessment note covers what it does and does not resolve.

Seasonality, weather and the access reality

Seasonality is not a detail in forestry survey; it is a design parameter. Leaf-on and leaf-off acquisition measure different things, and for any programme that will be repeated, the season must be fixed so epochs remain comparable. Decide which state answers your question — for terrain and stem structure, leaf-off is usually better; for species and health, leaf-on usually is — and hold it across years.

Remote forest terrain brings a specific set of operational constraints: limited launch sites, poor or absent connectivity, long transit, and weather that changes quickly with elevation. Connectivity matters more than teams expect, because it affects whether data can be verified on site or only after return. Plan for offline verification: enough onboard storage, a field check procedure that does not require a network, and a clear rule about re-flying uncertain sorties.

Wind over forest behaves differently from wind over open ground, with shear and turbulence at the canopy edge. Launch and recovery sites should be clearings with enough separation from the canopy, and the flight plan should account for the fact that the air at cruise altitude may be moving quite differently from the air at the launch point.

From raw capture to a usable inventory

The gap between acquired imagery and a forestry deliverable is larger than inmost survey disciplines, because the deliverable is a set of derived metrics rather than a map. Canopy height models, plot-level metrics, species classification and volume estimates eachrequire their own processing chain and their own accuracy assumptions, and each can fail independently of the flight.

Ground truth is the part most often omitted and most often regretted. A set of measured field plots, tied to the airborne data, is what turns a canopy model into a calibrated estimate rather than a relative one. Plan for field plots from the start — they are a ground task with real cost, and treating them as an afterthought is the difference between an inventory and a picture of a forest.

Decide the output format early. Forestry deliverables usually have to enter an existing inventory or GIS system with its own schema and tolerances. Our GIS platform integration work covers the adaptation required when the airborne output does not match the receiving system's expectations.

Configuring a forestry programme

The configuration we would propose separates wall-to-wall canopy acquisition from plot-level detailed acquisition, uses the sensor that the deliverable actually requires rather than the most capable one available, and fixes the season and the geometry so that future epochs remain comparable. Field plots are scoped as part of the programme, not added later.

Where the requirement includes non-standard sensors, specific inventory schemas, or survey designs that differ from a standard block, treat it as engineering scope. Our custom forestry survey systems track covers that path from requirement discovery through field testing.

Send your area, the metrics you need, the deliverable schema, the season you can fly, and your access constraints to our engineering team. We will propose the tiered acquisition design, the sensor set and the sortie estimate, and we will say plainly where a standard configuration is sufficient and where it is not.