Helps determine success of projects
Knowing what a forest is really like – the size and spacing of trees, and how needles, branches and woody material are scattered on the ground – is essential information for understanding forest health and wildfire risk. But it’s not efficient to survey hundreds or thousands of acres on the ground or from a clearing in the forest.
Last month, the Washington Department of Natural Resources (DNR) tested new technology using a drone and cutting-edge LIDAR technology to obtain a detailed bird’s-eye view of the forest around Virginia Ridge and Wolf Creek.
The drone – not a common consumer model, but a powerful instrument about 4 feet in diameter – carried a special camera and laser for LIDAR modeling to produce images of the forest floor that can be viewed from all angles, according to the representative from an Alabama-based LIDAR company in town to show DNR the technology.
Getting this in-depth look at the forest around Wolf Creek was also an opportunity for DNR to evaluate the success of a 670-acre forest health project and timber sale completed two years ago.
One goal was to see if the agency met the overall goals of the treatment – leaving trees in irregular clumps to look more natural and to increase fire resistance, DNR Communications Manager Ryan Rodruck said.
Traditional modeling is done on the ground at a handful of field plots to look at trees, woody material and grasses, but that covers only a small fraction of an area, DNR Forest Health Scientist Derek Churchill said. DNR used the drone to survey 50 acres of the treatment, providing a clearer picture of the whole area.
By analyzing data from the LIDAR imagery, DNR foresters can determine the effectiveness of the treatment. This detailed information also lets them adapt their approach when planning future forest health treatments and prescribed burns.
Because the sensor is relatively heavy, batteries can keep the drone aloft for only 17 minutes at a time, meaning the operator has about eight minutes before it has to turn around, Churchill said. The drone is designed to return home immediately if it’s running low on battery power.
Detailed monitoring is part of DNR’s 20-Year Forest Health Strategic Plan, to evaluate how stands are growing back after treatment and whether additional treatments are necessary, Churchill said.