Estimating Riparian Vegetation Geometry and Biomass from LiDAR Point Clouds

In non -arid environments, the evolution of rivers and floodplains is an eco-morphodynamic process conditioned by riparian vegetation dynamics and continuous feedback among plants, water, and sediments. Because of these mutual interactions, proper quantification of vegetation geometry and biomass in riparian corridors is needed to carry out realistic eco-morphodynamic fluvial modeling and support the management of riverine ecosystems. The use of remote sensing in river sciences has notably increased in recent years, emphasizing the application of Light Detection And Ranging (LiDAR) at different scales, from single fluvial bars up to river reaches. Nevertheless, despite forestry having a long experience in LiDAR-based vegetation inventory, the transfer of knowledge to eco-morphodynamic applications still needs to be addressed appropriately. The present work aims to explain why LiDAR has started to be employed for vegetation inventory and how it may support eco-morphodynamic modeling. After introducing the different approaches to performing plant inventory with LiDAR point clouds, we present two methodologies that we have recently defined to map and measure individual trees and shrubs along rivers and highlight their strengths and weaknesses. These methods integrate targeted field measurements with LiDAR datasets and can be combined in a single innovative procedure. By referring to the Orco River case in northwest Italy, we show the procedure applications, opening up for discussion about future developments in this direction.