Mapping natural forest stands with low cost drones

Thomas Williams, Brian Williams, Bo Song, Jeremy Forsythe, Thomas L O'Halloran


We used a low cost hobby drone to produce high resolution aerial photographs of a 12 ha mature longleaf pine (Pinus palustris) stand. The photos were combined into orthophoto mosaics and digital surface models to produce repeatable crown maps. Repeated flights allowed the use of tree phenology to separate longleaf from loblolly (Pinus taeda) and pond (Pinus serotina) pines, as well some hardwood species. Aerial crown maps and field measured stems did not produce 1:1 correspondence. However, average stems and crown area/basal area ratio of 15 m radius plots produced correlation coefficients comparable to open single tree measures. Height of tallest trees also was relatively well correlated for larger longleaf trees but had a positive bias greater than 1 m. The most difficult problems were determining the number of stems associated with a mapped crown area and determining a correction for the true ellipsoid height of the camera.


Structure from Motion, tree delineation, plot inventory, longleaf pine, southeast US

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