Evaluating the effect of tree position on crown area, height, and crown asymmetry in Silvopastoral systems using drone laser scanning (DLS)-based segmentation

Silvopastoral systems (SPS) represent a promising approach to sustainable land use by integrating trees with livestock production. In SPS, the spatial arrangement of trees plays a significant role in crown development. Edge trees, located at the plantation perimeter, are particularly important in alley arranged SPS, as they are the most prevalent and exhibit distinct structural characteristics. The study evaluates the effects of tree position on crown asymmetry, Crown Area (CA), and height (Ht) in a triple-row silvopastoral system using Drone Laser Scanning (DLS) data. The research was conducted on two Eucalyptus grandis stands, 3 and 10 years old. Inverted watershed segmentation method was used to estimate dendrometric variables such as CA and Ht, and trees were classified based on their position within the triple-row arrangement into three categories: external east (EE), external west (EW), and middle (M). Crown asymmetry was analyzed using six indices (CAI4, CAI5, CAI10, CAI13, DistTC, Dist/CA). Results demonstrated significantly larger CA in external trees (EE and EW) compared to middle trees, reaching differences of up to 39% in the 10-year-old stand. In contrast, tree height showed minimal positional differences (1–3%). Crown asymmetry indices (CAIs) were strongly correlated (Spearman’s ρ = 0.83–0.99), with CAI13, CAI10, and CAI4 showing particularly high consistency. This research highlights the importance of tree position in determining crown structure and demonstrates the effectiveness of remote sensing technologies for precise dendrometric assessments, informing better management and design of sustainable silvopastoral systems.