Sherwood Pines mapped in 3D.

By Roberto Vargas, 3D Laser Mapping

As global temperatures rise, wildfires are becoming more common and intense. South Africa is particularly prone to such events, including the recent outbreak in Knysna last year. Nine people were reported dead and over 10,000 people were evacuated in fires following the Cape Town region’s worst drought in a century. Increasing temperatures and decreasing rainfall, combined with natural grassland, fynbos and indigenous forests, all make South Africa a prime candidate for such wildfires and that is not set to change. Mapping the effects of wildfires has long been a tool to measure damage, yet new technology is now available to help make wildfire prevention more of a reality.

Creating fuel models to simulate fire behaviour can be critical when it comes to mitigating loss of life and property damaged by fire. In commercial forestry operations, wildfires can also devastate a plantation in a matter of hours, with years of hard work going up in smoke. Light Detection and Ranging (LiDAR) is one of the latest technologies being used to help map, monitor and manage the spread and damage caused by wildfires.

Additionally, LiDAR is a tool which is starting to see widespread use for precision forestry and agricultural applications, as well as in civil engineering and infrastructure management. The technique uses pulsed light from a laser to take accurate measurements of the surrounding environment, with the ability to create 2D and 3D representations of a topographical area. Measurements are calculated by how long it takes for the pulsed light to return to the scanner, with additional geographical positioning being provided by an Inertial Measurement Unit (IMU) and GNSS.

For forestry applications, LiDAR’s most important attribute is its ability to scan through dense vegetation. Airborne systems such as ROBIN +WINGS are capable of collecting a million measurements, or returns, per second, providing detailed information from the top of the tree canopy, down to the forest floor.

Forest by height to show canopy dynamics and Leaf Area Index (LAI).

This enables accurate measurements of the three-dimensional structure of the canopy and stands to give an efficient estimation of fuel characteristics. These calculations can help create simulated fuel models for both preventing the spread of fires, and carrying out more controlled clearance fires.

Mobile mapping systems offer the opportunity to scan difficult to reach areas either on foot, from a vehicle or from the air. Scanners can be mounted on a backpack, all-terrain vehicle and/or a helicopter, producing a three-dimensional digital terrain model. Now more than ever, geospatial and forestry experts are able to gather critical biomass information to the most accurate degree possible.

Laser scanning systems are also useful for creating 3D maps of vulnerable critical infrastructure such as powerlines and highways, which can help when forestry operations encroach on urban areas. Airborne LiDAR systems provide insight as to how such infrastructure could be affected or protected in the event of a wildfire, limiting the risk of permanent damage or allowing response crews to plan routes and evacuation procedures in advance.

Drones
Another disruptive technology helping to fight devastating fires are drones, also known as Unmanned Aerial Vehicles. UAVs are helping fire and rescue crews to fight domestic and natural fires across the globe, thanks to the ability to assess the affected area remotely. Emergency services, specifically fire services, are benefitting greatly from the ability to assess situations from the air, without having to pose danger to the lives of pilots, or risk fanning the flames even further. Integrated cameras provide real-time information to show the spread and scale of a fire to allow crews to strategise with more clarity. Another benefit of UAVs is the speed at which they can be deployed following an incident. A UAV can take to the air and provide immediate intelligence, moments after first responders arrive at the scene. Drones also provide a cost-effective way of collecting data to create fire models prior to an incident, with the ability to monitor the ever-changing landscape on a more regular basis.

Digital Terrain Model to show terrain changes.

Advancements in drone technology has also seen them become capable of carrying heavier payloads than previously possible, making UAV LiDAR systems a viable reality. Using a combination of multispectral imaging and LiDAR data, an immeasurable visual picture can now be created to assist in fire strategy and management. Photogrammetry techniques alone are often not accurate enough to provide all of the intelligence needed in an area at risk of forest fires. The precision provided by LiDAR can make all the difference when it comes to accurately predicting fire behaviour.

UAVs and LiDAR both hold significant benefits for any forestry operation, outside of just fire prevention and management. Both systems offer the ability to remotely capture data for a variety of uses, from canopy detail in hard to reach areas to critical biomass information to assess the health and stability of an operation. While natural disasters such as forest fires can and will happen, the ability to deploy technology to minimise the risk as much as possible is of huge importance. The operational intelligence and scope for the use of LiDAR in the forestry sector also presents a real opportunity to map and model the spread of wildfires for a safer and more profitable future for all.

Info
3D Laser Mapping provides 3D technology across the UK, South Africa, USA and Australia via its network of branch offices and international distributors.
Email: dan.trussell@tankpr.co.uk / scott.giles@tankpr.co.uk

*First published in SA Forestry magazine, March 2018