Mapping Understory Vegetation Density in Mediterranean Forests: Insights from Airborne and Terrestrial Laser Scanning Integration

Abstract

The understory is an essential ecological and structural component of forest ecosystems. The lack of efficient, accurate, and objective methods for evaluating and quantifying the spatial spread of understory characteristics over large areas is a challenge for forest planning and management, with specific regard to biodiversity and habitat governance. In this study, we used terrestrial and airborne laser scanning (TLS and ALS) data to characterize understory in a European beech and black pine forest in Italy. First, we linked understory structural features derived from traditional field measurements with TLS metrics, then, we related such metrics to the ones derived from ALS. Results indicate that (i) the upper understory density (5–10 m above ground) is significantly associated with two ALS metrics, specifically the mean height of points belonging to the lower third of the ALS point cloud within the voxel (HM1/3) and the corresponding standard deviation (SD1/3), while (ii) for the lower understory layer (2–5 m above ground), the most related metric is HM1/3 alone. As an example application, we have produced a map of forest understory for each layer, extending over the entire study region covered by ALS data, based on the developed spatial prediction models. With this study, we also demonstrated the power of hand-held mobile-TLS as a fast and high-resolution tool for measuring forest structural attributes and obtaining relevant ecological data.

Digital Forests: innovations and opportunities

“…Più sofisticato è l'impiego del Terrestrial Laser Scanning (TLS), in modalità fissa o mobile, che può fornire informazioni dettagliate (con precisione centimetrica e subcentimetrica) e 3D sulla posizione, dimensione e forma dei fusti arborei, nonché dati sulla struttura dell'intero popolamento forestale (Puletti et al 2021a, Ferrara et al 2023) (Fig. 1).…”

crossing3dforest: an R package for evaluating empty space structure in forest ecosystems

“…The assessment of the attributes beneath the forest canopy is becoming increasingly important in understanding forest ecosystem processes and services, but it is challenging to capture in traditional forest surveys (Ferrara et al, 2023). Although conventional measurements are essential for pre-standardized management decisions, TLS nowadays can significantly improve quantitative monitoring issues in forest environments.…”

Low-Cost 3D Virtual and Dynamic Reconstruction Approach for Urban Forests: The Mesiano University Park

“…Traditional data acquisition systems are based on two separate procedures, inventory and mapping, but this division is a limitation [6]; for example, it does not allow changes in time and space to be observed. Digital procedures for data acquisition could overcome the limitations of traditional systems [13,14].…”