Determination of Riparian Vegetation Biomass from an Unmanned Aerial Vehicle (UAV)

The need to rely on accurate information about the wood biomass available in riparianzones under management, inspired the land reclamation authority of southern Tuscany to developa research based on the new remote sensing technologies. With this aim, a series of unmanned aerialvehicle (UAV) flight campaigns flanked by ground-data collection were carried out on 5 zones and15 stream reaches belonging to 3 rivers and 7 creeks, being representative of the whole area undertreatment, characterized by a heterogeneous spatial distribution of trees and shrubs of differentsizes and ages, whose species' mix is typical of this climatic belt. A careful preliminary analysis ofthe zones under investigation, based on the available local orthophotos, followed by a quick pilotinspection of the riverbank segments selected for trials, was crucial for choosing the test sites. Theanalysis of a dataset composed of both measured and remotely sensed acquired parameters alloweda system of four allometric models to be built for estimating the trees' biomass. All four developedmodels showed good results, with the highest correlation found in the fourth model (Model 4, R2 =0.63), which also presented the lowest RMSE (0.09 Mg). The biomass values calculated with Model4 were in line with those provided by the land reclamation authority for selective thinning, rangingfrom 38.9 to 70.9 Mg ha-1. Conversely, Model 2 widely overestimated the actual data, while Model1 and Model 3 offered intermediate results. The proposed methodology based on these newtechnologies enabled an accurate estimation of the wood biomass in a riverbank environment,overcoming the limits of a traditional ground monitoring and improving management strategies tobenefit the river system and its ecosystems.