Using LiDAR for forest and fuel structure mapping: options, benefits, requirements and costs

Abstract

Understanding fuel structure is important for assessing suppression difficulty, risk of damage from bushfires, monitoring fuel build up and planning hazard reduction programs. Technologies such as airborne Light Detection and Ranging (LiDAR) can provide precise information about fuel structure over larger areas. However, the use of LiDAR by fire managers is still in the early stages and has not been implemented through any routine operational program in Australia. This report aims to address this situation by describing and evaluating the maturity and suitability of airborne LiDAR to derive the different types of information needed in forest fuel assessment. It does so through a set of questions scoped in consultation with fire managers through the Bushfire and Natural Hazards CRC project ‘Mapping bushfire hazard and impacts’. The language and technical detail is aimed at a wide audience with fields of expertise outside LiDAR. This report first covers some of the basic principles on LiDAR and then focuses on the analysis of the information content and accuracy of airborne LiDAR to retrieve the forest fuel attributes that are important for fire management. The information that can be derived about the height, cover fraction and density of different over‐ and understorey layers is assessed, along with other useful information that may be derived. Additional measurements that help to make more optimal use of airborne LiDAR data are presented, including terrestrial laser scanning, UAV‐borne LiDAR, and airborne imaging. Guidance is provided on discovering existing LiDAR data, factors determining the cost of new LiDAR data acquisition, and options for processing the data. Finally, the current and future development in the use of LiDAR for fire management are discussed. Summarising, airborne LiDAR may be considered a mature data product that is commercially available, using established data standards. However, standardised data specifications and processing methods for applications in fuel mapping do not yet exist. Essential aspects to consider are the type of fuel information, accuracy and spatial detail desired. Greater data density can increase accuracy and spatial detail, but will also increase the cost of acquisition. In forests with a dense overstorey canopy high data density may be the only way to obtain information on the understorey. In small‐scale applications, field or UAV‐mounted LiDAR systems may be a suitable alternative for airborne LiDAR. Priority areas for research and development to achieve more cost‐effective and successful use of LiDAR by the fire management community were identified. This includes the development of standardised methods to acquire and process airborne LiDAR data for fuel mapping, the validation of these methods using field measurements, and investigation of full‐waveform airborne LiDAR as a promising alternative to current LiDAR data collection methods. The Bushfire and Natural Hazards CRC project ‘Mapping bushfire hazard and impacts’ is working with end users to pursue each of these lines of enquiry Show more