6/17/2023 0 Comments Agisoft license![]() ![]() Because the material and operational cost of lightweight UAVs is low, they can acquire digital photographs at a lower cost than a manned aerial vehicle with increased spatial and temporal resolution. Lightweight unmanned aerial vehicles (UAVs) may be a suitable platform for acquiring digital aerial photographs for small areas at low cost. The dominant tree type improved estimation accuracy. Thus, a lightweight UAV photogrammetric point cloud could accurately estimate forest biophysical properties, and a spectral variable was not necessarily required for the estimation. The model including a spectral variable alone yielded much lower estimation accuracy than that including a height variable. The model including a height variable alone yielded the second highest accuracy. The root-mean-square errors (RMSEs) for the best model for V, H L, H A, and H M, were 118.30, 1.13, 1.24, and 1.24, respectively. The model including a height variable and dominant tree type was the best for all biophysical property estimations. The addition of a dominant tree type to the above data sets was also tested. We developed three independent variable sets, which included a height variable, a spectral variable, and a combined height and spectral variable. We estimated four biophysical properties: stand volume ( V), Lorey’s mean height ( H L), mean height ( H A), and max height ( H M). Here, we investigated the capabilities of a lightweight unmanned aerial vehicle (UAV) photogrammetric point cloud for estimating forest biophysical properties in managed temperate coniferous forests in Japan, and the importance of spectral information for the estimation.
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