By Jim Stirling

Unpredictable and extreme weather patterns have become routine. Consistently warmer and drier years are placing new strains on forest ecosystems. Trees are becoming increasingly stressed and dehydrated by the prolonged changes, making them more vulnerable to attack from beetles, rusts and other pests and ripe for the ravages of wildfires.

There are more than 8,000 forest fires each year in Canada. In many cases their behaviours are changing with the climate. Their ferocity and changeability ushers new definitions of catastrophe. The Fort McMurray inferno last spring is one chilling example.

Those charged with containing and extinguishing wildfires are testing and investing in an increasingly technology-driven arsenal of tools. Unmanned aerial vehicles—or drones—are one example.

Larry McCulloch had his moment of drone epiphany when he witnessed a drone undergoing testing in Alaska a few years ago. “I knew immediately it offered a range of practical forestry applications,” he recalled. And so it has proved. McCulloch is principal with L.M. Forest Resource Solutions Ltd., based at Smithers in west central British Columbia. The company has been offering a range of resource management services to its clients since 1986.

The acquisition of and experience with drones during the last three years offer a new range of opportunity and potential for forest and other natural resource managers requiring precise, detailed information in close to real time. The ability of a drone carrying purpose-designed cameras delivers the types of information that give wildfire control managers an advantage in allocating resources safely and more effectively.

McCulloch’s company operates three types of drone to suit different applications. There’s a DJI S900 hexacopter (six rotary blades) manufactured in China and teamed with a 36 megapixel Sony A7R full frame camera. McCulloch says the S900 can operate for about 15 minute assignments. The latest acquisition to the company’s fleet is a DJI Matrice 600 which can operate for about 30 minutes at speeds around 60 kilometres per hour. The Turboace Matrix E drone with Sony A7 camera represents less of a payload and can work for about half-an-hour at speeds up to 100 kilometres per hour.

Transport Canada regulations control the use of drones. The devices have become increasingly popular for a wide variety of recreational and other users. L.M. Forest Resource Solutions has been granted a special flight operations certificate from Transport Canada to operate its drones commercially.

Drone use is typically limited to a height of around 100 metres with a visual line of sight maintained. An advantage of flying higher is that more ground can be covered, but the trade-off is the images produced by the cameras have less resolution. McCulloch says the high resolution cameras he employs on his drones can deliver on-ground accuracies from less than one centimetre per pixel to three centimetres. By way of comparison, when the B.C. Forest Service flies an area to update forest inventory information, the imaging collected is in about 20-30 centimetres per pixel range, he says.

The thermal sensing imagery directed by a drone has several applications for the B.C. Wildfire Management Service in terms of suppression and detection.

“We can get accurate temperatures of a fire as it’s burning and identify hot spots in the mop-up stages,” explains McCulloch.

Wildfires will frequently follow root systems and can persist underground for months. They can then flare up again when temperatures and ground conditions allow. Detecting and dealing with the fire risk initially can prevent a lot of later grief.

“The drones can also scout out areas too dangerous for people to access,” adds McCulloch. “They can provide critical information about the behaviour at the head of the fire and check out things like available water sources.”

Accurately interpreting the data collected by the drone’s cameras is key. Computerized software can produce detailed three-dimensional models of a given area. The height, species and diameter of individual trees can be calculated along with information like their crown areas, he continues. A wealth of detailed forest land information can be gleaned from the drone’s imagery. Road grade details and timber volumes, for example, along with the volumes of materials like gravel in a given location. A model can be produced that strips tree and surface cover to reveal the nature of the bare earth beneath. “It’s amazing what you can do with the technology.”

McCulloch says L.M. Forest Resource Solutions is working with the B.C. Forest Service to incorporate drone-delivered image technology to provide accurate forest fuel loading data. The amounts of on-ground fibre affect the speed and intensity of forest fire development. The information is useful in many ways including being able to better predict fire behaviour and in helping indicate areas where “fire-proofing” communities or infrastructure is most required.

Forest Pest detection is a further intriguing potential for a drone fitted with a multi spectral camera, reckons McCulloch. The technology could be applied to identify the presence of stem rusts, for example, before changes in colour occur. And similarly, the camera could pinpoint trees under attack from the spruce bark beetle. The spruce beetles, unlike their mountain pine counterparts, stay within a tree, undetected by any outward signs until the infestation is well advanced. A drone with the appropriate camera could provide an early warning system for where an infestation lurks and from that, where it might be reasonably anticipated to spread.