Competition modulates growth in Pinus canariensis plantations: Implications for precision thinning

: Competition is a key driver of tree growth and stand dynamics; yet, in managed forests, its structural dimension remains insufficiently understood. Here, we analyzed how competition intensity and structure modulate growth responses to thinning in Pinus canariensis plantations and assessed the potential of light detection and ranging (LiDAR)-derived metrics to upscale competition-driven processes for precision forestry. Using individual-tree data from a long-term thinning experiment, we combined multiple competition indices that capture vertical, spatial, and size-related interactions, and fitted generalized linear models with a Gamma distribution to explain post-thinning basal area. We further characterized the structure of competition using a proxy for competitive entropy and linked field-based indices with LiDAR-derived structural metrics. LiDAR data were not collected before thinning. Treatments included control and three thinning intensities (30%, 60%, and 70% of basal area removal). Thinning enhanced basal area increment (BAI, mm 2 ·tree −1 ·year −1 ), with positive effects for all intensities. Intermediate thinning, with 60% basal area removal, produced the most consistent BAI gains, whereas higher intensity treatment showed increased interannual growth variability. Competition indices representing vertical structure (RK 4 ) and spatial crowding (Braathe) provided the best performance (pseudo- R 2 ≈ 0.85–0.86) in models of post-thinning BAI, highlighting the dominant role of canopy stratification. Competitive entropy indicated moderate but heterogeneous competition, with a marginal treatment effect ( p = 0.088), suggesting that thinning reshapes competition. Management zones based on dominant competitive processes were delineated using LiDAR metrics. Our approach allows thinning to be targeted according to competition structure, thereby moving towards precision interventions. Growth responses to thinning were found to be primarily driven by the structure of vertical competition for light. Therefore, precision thinning should focus on canopy structure to enhance resilience to drought. Similar frameworks could integrate growth and competition metrics with LiDAR-based measurements to provide a tool for precision thinning aimed at enhancing drought resilience, optimizing stand productivity, and promoting structural heterogeneity through spatially variable thinning prescriptions.