Following initial combustion of carbon (C) pools, fire can alter watershed C dynamics for decades to come. Fire transforms landscapes by altering soil organic matter (OM), vegetative community composition, hydrologic pathways, and, thus, the processing of C. This study investigates how shifts in terrestrial C dynamics affect the export and fate of OM within streams draining mesic montane landscapes. Stream OM chemistry, C isotopic composition, and metabolism metrics were characterized in streams draining three watersheds within the 2002 Hayman and Schoonover burn scars and two watersheds unaffected by fire. Water yield increased significantly with the extent of watershed burned (%) as burned landscapes experience less evapotranspiration and generate more runoff. While soil in burned areas contains ~73% less OM, stream dissolved organic carbon (DOC) concentrations were not different between landscapes and DOC yield increased with burned extent. This suggests that a larger fraction of soil OM is exported from burned soils. The δ13C of stream DOC and DIC reveals a dominance of terrestrially derived sources. DOM exported by burned landscapes is less aromatic, indicating a difference in dominant terrestrial sources. Stream metabolism metrics, calculated using continuous in situ sensors, indicate that streams are predominantly heterotrophic systems, dominated by ecosystem respiration (ER). Variations in δ13C-DIC, estimated ER, and DOC aromaticity indicate temporal shifts in C sources and fate in forested watersheds, which are absent in burned watersheds. The greater fraction of C exported in burned watersheds may be another positive feedback, inhibiting recovery. Thus, warmer, drier climatic conditions may lead to new steady state ecosystems on fire impacted landscapes; shifting mesic montane landscapes to those consisting of grasses and forbs with little tree growth.