Rapid assessment of forest regeneration using unmanned aerial vehicles (UAVs) is likely to decrease the cost of establishment surveys in a variety of resource industries. This research tests the feasibility of using UAVs to rapidly identify coniferous seedlings in replanted forest-harvest areas in Alberta, Canada. In developing our protocols, we gave special consideration to creating a workflow that could perform in an operational context, avoiding comprehensive wall-to-wall surveys and complex photogrammetric processing in favor of an efficient sampling-based approach, consumer-grade cameras, and straightforward image handling. Using simple spectral decision rules from a red, green, and blue (RGB) camera, we documented a seedling detection rate of 75.8 % (n = 149), on the basis of independent test data. While moderate imbalances between the omission and commission errors suggest that our workflow has a tendency to underestimate the seedling density in a harvest block, the plot-level associations with ground surveys were very high (Pearson’s r = 0.98; n = 14). Our results were promising enough to suggest that UAVs can be used to detect coniferous seedlings in an operational capacity with standard RGB cameras alone, although our workflow relies on seasonal leaf-off windows where seedlings are visible and spectrally distinct from their surroundings. In addition, the differential errors between the pine seedlings and spruce seedlings suggest that operational workflows could benefit from multiple decision rules designed to handle diversity in species and other sources of spectral variability.
Related Resources
2BT Science Note 18: Planting the Right Trees in the Right Places in Forests and in Cities: Adaptability of Red Oak to Climate Change
Resource Date:
2023
Organization
2BT Science Note 17: Tools to Facilitate Forest Planting and Seed Transfer Under Climate Change
Resource Date:
2023
Organization
2BT Science Note 15: The Application of Wood Ash and Effects on Tree Growth Rate
Resource Date:
2023
Organization
2BT Science Note 14: Utilizing Remotely Sensed Data to Support Effective Planning and Monitoring of Forestation Efforts in Newfoundland and Labrador
Resource Date:
2023
Organization
2BT Science Note 13: Tree Planting 101 in the Northwest Territories
Resource Date:
2023
Organization
Was this helpful?
|