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Abstract Stemflow is a conduit for the transport of canopy-derived dissolved organic matter (DOM) to the forest floor. This study examined the character of stemflow DOM for four tree species over four phenophases (leafless, emergence, leafed, and senescence for deciduous species and leafed-winter, emergence, leafed- spring/summer, and senescence for coniferous species) occurring in temperate forests; namely,Betula lentaL. (sweet birch),Fagus grandifoliaEhrh. (American beech),Liriodendron tulipiferaL. (yellow poplar), andPinus rigidaMill. (pitch pine). American beech exhibited the lowest average specific UV absorbance at 254 nm (SUVA₂₅₄) values, while yellow poplar displayed the highest values. SUVA₂₅₄values were largest in senescence and smallest in emergence. The spectral slope ratio was lower for pitch pine than the deciduous tree species. Humification index (HIX) values decreased across all species during the emergence phenophase. The developed and validated stemflow-specific four-component parallel factor analysis (PARAFAC) model demonstrated the combined influence of interspecific and temporal fluctuations on the composition of humic and protein-like substances within stemflow. By separating and examining stemflow DOM independent of throughfall, our study provides fresh insights into the spatiotemporal dynamics of stemflow inputs to near-trunk soils that may inform hot spots and hot moments theories.