What is LiDAR?

LiDAR, short for light detection and ranging, measures distance with laser pulses. Wikipedia describes it as "a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the optical receiver". Fired many thousands of times a second from an aircraft, drone or ground scanner, the pulses build a three-dimensional point cloud of whatever they hit.

In forestry

A LiDAR point cloud of a forest captures canopy height, tree positions, crown shapes and the ground beneath. From it, models estimate stand attributes: height, density, basal area and volume. Airborne scans cover whole ownerships. Mobile and terrestrial scanners measure individual stems in detail.

There are two main ways to turn the cloud into inventory. An area-based approach relates point cloud statistics to field plot measurements, then predicts across the whole area. An individual tree approach finds each tree in the cloud and measures it.

How accurate it is

It depends on what it is checked against. A 2025 trial by Sparks and colleagues notes that "few studies have quantified errors in field sampling- and airborne laser scanning (ALS)-derived inventories at the stand level". In one mixed conifer forest, it checked a field cruise and LiDAR inventories against logs scaled at the mill, and found "similar errors". The LiDAR methods ranged from minus 8 to 6%, the cruise from minus 16 to 6%.

Mill scale isn't a perfect reference either. It measures merchantable logs after bucking and breakage, from what was harvested, while an inventory estimates what stood. Our piece on LiDAR accuracy in published trials covers this in more depth.

What it isn't

LiDAR isn't an inventory on its own. On its own it measures structure, not species or grade, and it needs field data and models to turn points into volumes. Nor is it the only remote sensing method: optical satellite imagery covers larger areas more often, at lower detail.

What to check

Ask what reference any accuracy figure used, field plots or harvested volume. Ask whether the figure is per plot or per stand. And where you have scale tickets linked to stands, check the inventory against them after harvest.

Quarri for forest management is built around how a forest operation runs, from the cruise to the settled account.

Quarri is an AI-native data platform for the timber supply chain. It connects buying, production, sales and inventory for forest management, sawmill, wood products and pulp, paper and packaging operators.