Temporary carbon storage and substitution benefits of harvested wood products (HWPs) aid in mitigating global warming. However, the extent of this effect remains unclear. Current studies typically rely on a simple summation of the annual carbon sink. This method overlooks the fact that, due to radiative forcing delay, each ton of carbon sequestered has an impact on global warming, which dynamically changes year by year. Such an oversight could lead to an underestimation of HWPs' contribution to global warming mitigation. This study focused on a forestry resource-based city in Northeast China and utilized the Carbon Budget Model for the Canadian Forest Sector (CBM-CFS3) and dynamic life cycle assessment (DLCA) to quantify the dynamic global warming impact (DGWI) of forestry biogenic carbon. The results indicate that: 1) From 2020 to 2120, the maximum DGWI could reach −42.70 Mt CO2e. Enhancing the collection and utilization of harvesting residues and promoting products with longer lifespans and higher substitution potential can further increase these benefits. 2) The DLCA method, integrating substitution effects, offers a more precise evaluation of forestry's climate mitigation benefits. Across all scenarios and periods in this study, HWPs' contribution to mitigating global warming, as calculated by the DLCA method, exceeds that estimated by the simple carbon sink summation method by 7.70 %–560.72 %. These findings help to delve deeper into the role of forests in emission reduction and carbon sequestration, providing important references for achieving sustainable forestry management.