Photobleaching experiments with water-extracted dissolved organic matter (wDOM) from uncharred or charred grass (SG25 and SG400), softwood (EC25, AJ25, EC400, and AJ400), and hardwood (HM25 and HM400) biomass revealed that photodegradation proceeds along an energy-dependent, component-specific trajectory dictated by the nature of the aliphatic attachments associated with single-ring aromatic domains. Trends in wDOM photobleaching for both uncharred [EC25 = AJ25 (94%) > SG25 (46%) ≥ HM25 (43%)] and charred [EC400 = AJ400 (76%) > HM400 (55%) > SG400 (44%)] biomass pointed to biomass type and chemistry and its response to processing (here, charring) as key factors controlling photodegradation. Specifically, photobleaching was lower in wDOM where aliphatic attachments to the aromatic backbone had shorter alkyl chain lengths, was involved in heterocyclic ring formation, or was more oxidized. Photobleaching behavior, across the wDOMs, was captured by a three-component, UVA photoenergy (E UVA-V )based model comprising a fast, wDOM f , component requiring a mean E UVA-V flux of 42−204 kJ m −2 for photobleaching; a slow, wDOM s , component requiring a 3−24-fold higher E UVA-V flux; and a photobleaching resistant, wDOM res , component. Combining long-term daily E UVA-V across the State of Texas, the statewide distribution of vegetation types used in this study, and our photobleaching model suggested that an increase in the number of vegetation fires is likely to decrease photodegradative contributions to wDOM cycling in the conifer-dominated east, have no effect in the grass-dominated central regions, and increase contributions in the hardwood shrub-dominated west.