Understanding soil microbial responses to wildfires is critical for climate adaptation and ecosystem recovery. This study spans the Chilean Coastal Cordillera, from the Atacama Desert (arid) to a temperate forest, a fire-prone climatic gradient. We hypothesized that soil texture and porosity determine the resilience of microbial reactivation and enzyme activity following a wildfire. This study examined the impact of short-term (20 min) heating at 300, 600, or 900 degrees C on enzyme activity (beta-glucosidase, urease, peroxidase, and phosphatases), microbial biomass, and reactive oxygen species in four Chilean soils: arid, semi-arid, Mediterranean, and temperate. Furnace heating simulated near-surface wildfire exposure and was contextualized with a 1-D conduction model that yielded temperature-time profiles and cumulative thermal load (degree-hours). Responses scaled with thermal load, with higher exposure increasing soil organic matter (SOM) loss, reducing Vmax and biomass, and raising H2O2. After heating, the soils were cooled and incubated for 48 h under sterile conditions to isolate residual activity and early reactivation. At 900 degrees C, SOM retention was higher in temperate clay-rich soils (0.68%) than in arid sandy soils (0.02%). Within 48 h of heating at 300-600 degrees C, microbial biomass recovered to similar to 70% in temperate soils but remained <10% in arid soils. At 900 degrees C, the thermal load ranged from similar to 336 to similar to 1368 kJ across soils. Hydrogen peroxide concentration peaked at 3.5 mu mol g(-1) in semi-arid soils, indicating elevated oxidative stress. Peroxidase retained similar to 90% of its catalytic efficiency at 300 degrees C in temperate soils, whereas beta-glucosidase activity in arid soil dropped below 10% after heating at 900 degrees C. These findings confirm that higher porosity and SOM buffer the impact of heat, accelerate microbial reactivation, and mitigate oxidative stress. After accounting for initial soil C, N, and pH, texture effects persisted, reinforcing the need for targeted interventions in coarse-textured low-OM soils.