Use of the UAV technology in post-fire monitoring

A monitoring protocol for burned forest areas is described on the ground with phytosociological surveys and remotely with aerial photography in RGB with UAV. The study area, Monte Pisano in NW Tuscany, Italy (43°42’26” N; 10° 31’ 30”), was hit by a large forest fire in September 2019. The forest matrix of the study area was historically represented by Pinus pinaster forests of anthropogenic origin containing species of Quercion ilicis, especially Quercus suber, Quercus ilex, Arbutus unedo and Erica arborea. The repetition of fires has led to the disappearance of the pine forest and its replacement mainly by Q. suber forest. The use of the UAV at a low altitude (25 m, 0.45 mm pixel resolution) in inaccessible areas has proved to be of great utility in monitoring vegetation recovery. The use of high-definition orthophotos made it possible to recognize and measure the main shrub and tree species. Moreover, aerial photo processing with dedicated software and the development of dense point clouds enabled the description of the physiognomy of the phytocoenoses (height of the surviving trees, development of the shrub layer, size of the foliage) without the need for ground measurements.