Recent events in California highlighted the increasing risk wildfires pose to urban areas in a world where the impacts of climate change are becoming obvious.  In many regions of Australia, the urban fringe is especially vulnerable to bushfire, given the proximity of human habitation to highly combustible vegetation. 


Figure 1 The 2025 wildfires in California serve are a tragic reminder of the threat bushfires pose to the urban fringe of large cities.


With increased rainfall associated with the La Nina conditions of recent years, there has been significant vegetation growth across Australia’s eastern seaboard where over 80 percent of the population resides.  In particular, these conditions have seen a dramatic increase in potential bushfire fuel loads in the peri urban areas.  As such, there is an increasingly urgent need for action by local authorities to better identify and assess the potential threat to lives and property and to implement appropriate strategies to mitigate the risk in these urban fringe areas.

LiDAR data has long been relied upon by local authorities as a key dataset for disaster mitigation. Most notably it is used as the fundamental data for modelling and assessing the flooding and storm surge risk of populated areas due the ability to derive accurate terrain data over large areas.  It has also been utilised for assessing bushfire risk with its ability to not only model terrain but to provide detail of the vegetation of an area.  The latest generation of LiDAR systems offer a significant improvement in both resolution and accuracy and advance the effectiveness of LiDAR as a tool that provided critical metrics for vegetation structure, biomass density and fuel loads compared to the older generation of broadacre LiDAR scanners.

This think piece explores why the latest generation of aerial LiDAR, specifically the Riegl VUX-160 scanner operated by Bennett + Bennett, provides improved calculation of biomass and more reliable assessment of bushfire risk for Australia’s urban fringe areas. It will also highlight the unique capabilities of the VUX-160, demonstrating how it outperforms traditional broadacre LiDAR scanners in providing the best available data for use by professionals undertaking bushfire risk analysis.
Biomass and Bushfire Risk 

Biomass, the total mass of living and dead organic material, plays a key role in bushfire dynamics. Vegetation density, height, and structure along with vegetation species, directly influence the behaviour of a fire. Dense, multi-layered vegetation provides more fuel, resulting in larger and more intense fires that spread rapidly. In the urban fringe, where residential areas abut fire-prone bushland, high biomass levels can mean the difference between a manageable fire and a catastrophic event.

Figure 3 Most LiDAR sensors used for aerial capture have capability to measure multiple returns (or echo) per pulse.  This allows for capture of detail below vegetation canopy such as vegetation structure, understory canopies and terrain.

LiDAR operates by emitting laser pulses toward the ground, which bounce back to the sensor when the path of the beam is interrupted by an object such as vegetation, built structures or the ground. By measuring the time-of-flight, it takes for the laser to return, and combining this with GPS position data, LiDAR can generate a highly accurate 3D representation of the terrain and vegetation know as a point cloud. 

This point cloud data offers several advantages for bushfire risk assessment in the urban fringe:
1. High-Resolution Data: LiDAR provides high-accuracy data with fine spatial resolution, capturing even subtle variations in vegetation structure. This level of detail allows for the accurate calculation of biomass and the identification of areas with high fuel loads, which are critical for determining bushfire risk.

2. Vertical Vegetation Structure: Unlike traditional aerial and satellite imagery, which only captures the tops and the horizontal spread of vegetation, LiDAR data provides detailed information about the vertical structure of vegetation. The height and density of tree canopies, shrubs, and undergrowth are critical factors for understanding fire intensity. LiDAR data can identify these structural components and their potential to fuel bushfires.

3. Mapping of Canopy Gaps and Connectivity: LiDAR can map gaps in vegetation, such as open spaces between trees, which are crucial for understanding how fires will propagate. Fires spread more slowly in areas with canopy gaps or sparse low vegetation, while dense, continuous canopy areas and dense undergrowth create conditions for faster-moving and more intense fires.

4. Rapid and Cost-Effective Coverage: Aerial LiDAR can cover vast areas of difficult-to-access terrain quickly and at a fraction of the cost of traditional ground-based surveys. This is particularly valuable for large and sprawling urban fringe regions, which may be otherwise inaccessible for regular monitoring or manual biomass assessments.

5. Fuel Load Identification: LiDAR point clouds provide an accurate estimate of the volume of vegetation, which is essential for determining fuel loads. High fuel loads indicate higher bushfire risk. LiDAR data allows fire agencies to quickly and accurately identify areas that require fuel reduction such as cool burns or other mitigation strategies.


The Riegl VUX-160 LiDAR Scanner

The Riegl VUX-160 is a state-of-the-art airborne LiDAR scanner that provides superior data quality compared to traditional broadacre LiDAR systems. While other LiDAR systems are efficient at scanning large areas at low resolutions, the VUX-160 excels in delivering high-resolution, highly accurate point clouds, making it an ideal tool for assessing bushfire risk, particularly in complex urban fringe environments.

The Riegl VUX-160 stands apart from other broadacre LiDAR systems:

1. Higher Point Density and Precision: The Riegl VUX-160 has a higher point density than traditional LiDAR scanners. This means it can collect ultra-high point densities, providing finer detail and better resolution of vegetation structure. This is particularly important for accurately capturing the biomass and vertical structure of vegetation in fire-prone areas.

2. Improved Accuracy in Dense Vegetation: The VUX-160 is specifically designed to perform well in challenging environments, including densely vegetated areas. The scanner’s high precision allows it to accurately capture tree height, canopy density, and even lower vegetation layers, which are critical for bushfire risk assessments.


Figure 4 LiDAR point cloud data of the same vegetation displayed by return number.  The point cloud on the right shows the increased point cloud density and detail offered by the VUX 160  compared to LiDAR sensors optimised for broadacre capture.


3. Longer Range and Better Penetration: The VUX-160 has an extended range compared to many LiDAR systems operated by drone, allowing it to capture data from higher altitudes and penetrate through dense tree canopies. This enables the scanner to capture data over larger areas of bushland while still maintaining high accuracy. This is particularly useful in areas where access is difficult or where the vegetation is especially dense.

4. Efficiency in Large-Scale Surveys: In addition to its high precision, the VUX-160 can conduct large-scale surveys quickly, making it more efficient than other systems. This makes it ideal for surveying the expansive and often rugged urban fringe areas, where large-scale coverage is required.

5. Terrain Modelling under Tree Canopy: Understanding the topography is critical to understanding bushfire behaviour at a location.  The capability of the VUX-160 to capture high levels of detail even in areas covered by tree canopy vastly improves the modelling of elevation, slope and aspect consistently across large areas.

6. Real-Time Data Processing: The Riegl VUX-160 can process data in real time, which is critical for urgent bushfire risk assessments. Quick data processing means that fire managers can receive timely, actionable insights to make informed decisions about fire mitigation and response.


Practical Applications for Bushfire Risk in the Urban Fringe

In the context of bushfire risk in Australia's urban fringe, the Riegl VUX-160 LiDAR scanner offers several valuable applications:
1. Biomass Calculation, Fuel Load Mapping and Analysis
2. Fire Behaviour Prediction and Modelling
3. Bushfire Risk Mitigation
4. Post-Fire Assessment (Controlled burn assessment)
5. Visualisation, Community Awareness and Preparedness

Aerial LiDAR technology, particularly Bennett + Bennett’s Riegl VUX-160 scanner, represents a game-changing tool for biomass calculation and bushfire risk assessment in Australia's urban fringe. By providing high-resolution, accurate, and real-time data, LiDAR enables better informed decision-making for fire management, fuel reduction, and urban planning. Once captured. the data also has the added benefit to be used for other risk mitigation (flood studies, slope stability and geotechnical investigations) as well as being a standard resource that can be relied upon by local authorities and professionals that manage and maintain our towns and cities.

With the potential for the frequency and scale of bushfires to increase due to climate change and as our cities continue to expand creating new and increasing the footprint of peri urban areas, technologies like the Riegl VUX-160 will be essential for improving our understanding of fire behaviour, reducing risk, and protecting both lives and property in the urban fringe.


If you would like more information or wish to discuss your requirements please contact Bill Farry at Bennett + Bennett on 0482 909 096 or bfarry@bennettandbennett.com.au