Lidar technology for scalable forest inventory

5 June 2023
Evaluating the trade-offs between the various platforms

There is a critical need for rapid, rigorous, reproducible and scalable forest inventory tools to support data-driven policies and management practices in response to challenges including deforestation and climate change. Lidar technology offers an alternative for automated forest inventory at various scales, but each platform has trade-offs in terms of cost, efficiency, coverage, resolution or more. So, what is the solution?

Forest inventory programmes are varied in their scope and quality around the world Therefore, there is a critical need for rapid, rigorous, reproducible and scalable inventory tools.

With advances in sensor and algorithmic technologies, remote/near-proximal/proximal sensing – including imaging and Lidar systems onboard space/aerial vehicles, stationary terrestrial laser scanners (TLS) and terrestrial mobile Lidar – has recently been explored as an alternative for automated forest inventory at various scales.

These sensors/platforms have trade-offs in terms of cost, field survey efficiency, spatial coverage, spatial resolution and level of detail of the acquired information. Figure 1 shows two examples of potential data acquisition systems (near proximal and proximal) for fine-scale forest inventory.

Space imagery and airborne Lidar

Space imagery and Lidar data facilitate global and national forest inventory. However, limited spatial and temporal resolution would not allow for fine-scale inventory at the single tree level. Photogrammetric processing of images acquired by spaceborne and crewed aerial systems has attracted the attention of the forestry research community for estimating inventory attributes such as tree height, stem volume and basal area.

However, image-based point cloud generation is challenged by the difficulty in identifying corresponding points in overlapping images over forest landscape during both leaf-on and leaf-off conditions. Moreover, derived point clouds from imagery only capture the outer envelope of the forest canopy. Airborne Lidar provides large spatial coverage, fine resolution and the ability to represent the outer envelope and below-canopy structure.

Lower canopy mapping is facilitated by the fact that Lidar energy can travel through gaps among the trees/leaves and derive returns from tree trunks and terrain. Such ability makes Lidar an attractive modality for deriving ground slope and aspect, stem map, canopy height, crown dimension and leaf area index (LAI), to name but a few traits.

The large majority of airborne Lidar systems are based on linear Lidar technology, which is characterized by a high-power signal emission and a low-sensitivity receiver for detecting echo returns. Linear Lidar is based on emitted laser pulses with some nanosecond pulse width at wavelengths from 500nm (for bathymetric Lidar) to 1.5μm (for topographic Lidar).

The echo returns are then digitized by the receiver. To discriminate signal return from noise, linear Lidar utilizes a single-detector receiver that requires a flux of hundreds or thousands of photons. Such characteristics of linear Lidar impose constraints on the flying height, platform speed and lateral distance between neighbouring flight lines to ensure the delivery of point clouds with reasonable point density.

More >>

Source: gim-international

Read More

“Worlds-first” drive-by wireless charging for electric trucks

A world-first project will attempt to recharge heavy-duty electric trucks as they drive along roads in regional Australia, in a development researchers say could help accelerate adoption of low-emission transport. The AU$8.2 million project could also be used to wirelessly ...
Read more

JOUAV unveils advanced airborne Lidar sensor

JOUAV has released the JoLiDAR-1000 Lidar sensor designed specifically for uncrewed aerial vehicles (UAVs or ‘drones’) as the latest addition to its array of high-performance Lidar sensors for use in UAV applications such as GIS, surveying and precision powerline inspections. ...
Read more

Blenheim company turning wood chips into graphite

In New Zealand, a Blenheim company is turning wood chips and sawdust into graphite to be used in EV batteries. CarbonScape was founded in 2006 – with a focus on making carbon products using waste biomass like wood chips to ...
Read more

Boost to electrify Australian trucking fleets

Australian start-up NewVolt has revealed plans to build an electric truck charging network along the east coast of Australia, enabling the decarbonisation of the country’s major road freight routes and potentially saving billions of dollars spent on imported diesel a ...
Read more

30,000 machine milestone

Tigercat Industries is pleased to announce that it has built and shipped its 30,000th machine in January 2024, just over 30 years into its existence. From humble beginnings in 1992 when Tigercat had a single product, very little dealer representation, and produced just a handful of machines, the company has grown steadily, expanding both its production capacity and product breadth. A few quick facts Tigercat debuted the 726 feller buncher in April 1992 at a forestry equipment show in Quitman ...
Read more

Komatsu & Williams Racing reignite partnership

Leading heavy equipment manufacturer Komatsu has signed a multi-year deal with Williams Racing to become the Principal Partner of the British team from the start of the 2024 FIA Formula One World Championship (F1) season. Komatsu was a key partner ...
Read more