In the fire-prone tropical savanna landscapes of northern South America, forest edge effects significantly shape tree structural integrity and functional traits, with implications for ecosystem resilience, carbon storage, and biodiversity. This study examines how the edge effect, intensified by fire, affects species dominance, forest structure, and functional trait distributions in this region. Using non-metric multidimensional scaling (NMDS) and generalized additive mixed models (GAMMs), we analyzed changes in species abundance and structural variables (biomass, basal area, tree height, and wood density), as well as leaf (leaf thickness, leaf moisture, leaf dry matter content (LDMC), and specific leaf area (SLA)) and stem (bark and stem thickness and stem-specific density) traits across edge-to-interior gradients. The key findings indicate significant reductions in tree height (F = 19.27, p < 0.01), basal area (F = 6.52, p < 0.01), and biomass (F = 5.44, p < 0.01) near the edges. Leaf moisture (F = 11.8, p < 0.01) and specific leaf area (SLA, F = 7.02, p < 0.01) increased at the edges, reflecting microenvironmental gradients, with heightened fire sensitivity seen in traits like bark thickness (F = 11.88, p < 0.01). Fire-affected areas displayed intensified adaptive trait shifts, suggesting a compounded resilience but potential functional convergence, limiting adaptive capacity under climate stressors. These findings emphasize the ecological significance of edge–fire interactions, advocating conservation strategies to enhance structural and trait diversity for ecosystem stability. Our study underscores the need for targeted management to bolster resilience and biodiversity within these dynamic landscapes as climate pressures intensify.

Changes in land use, climate, and socio-ecology drive altered fire regimes that in turn reshape global ecosystems. Rapid afforestation with commercial tree plantations is transforming fire-prone savannas and grasslands globally and particularly in tropical South America, yet its effects on fire dynamics remain poorly understood. Using hierarchical models, we analyzed trends in annual burned area within concentric buffers (1–6 km) around each of 44 plantation and 52 grassland sites in Colombia’s Orinoquia region—a savanna grassland forest mosaic undergoing major land-use transitions from the expansion of commercial tree plantations. Plantations reduced burned areas in two ways: order-of-magnitude increases in plantation area reduced burnt area by 15% and plantation sites reduced their burnt area by 2% each year; both results consistent with trees replacing more inflammable grassland vegetation. While the mechanisms behind divergent savanna/plantation fire dynamics remain unresolved and could involve active fuel management and fire response, increased canopy cover, or some combination thereof, this study provides spatially explicit, context-sensitive evidence on how land-use transitions interact with fire regimes with direct relevance for savannas and grasslands management and climate adaptation policy in South America.