This study presents a numerical investigation into the fire resistance of thermo-mechanically densified Spruce wood using a kinetic pyrolysis model. Unlike conventional approaches that rely on simplified or generalized thermal degradation models developed for untreated bulk wood, this research emphasizes the necessity of incorporating the specific thermal decomposition behavior of wood’s primary constituents (hemicellulose, cellulose, and lignin). The densification process significantly alters the wood’s internal structure by reducing its moisture content and porosity, thereby changing its fire response characteristics. To accurately simulate these effects, a user-defined subroutine (UMATHT) was implemented in Abaqus to model heat transfer and material degradation under various heat flux conditions. The results demonstrate that the kinetic pyrolysis model provides a more realistic and reliable prediction of the degradation process in densified wood, offering valuable insights for fire-oriented design and performance-based safety assessments in structures utilizing engineered wood materials.