Assessing the Vertical Structure of Forests Using Airborne and Spaceborne LiDAR Data in the Austrian Alps

Vertical structure is an important parameter not only for assessment of the naturalness a forest and several functional parameters, such as biodiversity or protection from avalanches rockfall, but also estimating biomass/carbon content. This study analyses options assessing vertical by using airborne (ALS) spaceborne LiDAR data (GEDI) in mountainous near-natural Austrian Alps. Use GEDI waveform (L1B) still heavily underexploited assessments. Two indicators explaining are investigated this study: foliage height diversity (FHD) number layers (NoL). For estimation NoL, two different approaches were tested: break-detection algorithm (BDA) expert-based (EBA). The results showed that FHD can be used to separate three structural classes; separability slightly better ALS than on 25 m diameter plot level. EBA clearly outperformed BDA terms overall accuracy (OA) almost 20%. A OA NoL was achieved (49.5%) rather (44.2%). In general, limited difficult terrain forests with high structure. usability waveform-based parameters is, nonetheless, promising should further tested larger areas, including managed simpler stands.