Elucidation of turnover, preservation and stabilization pathways of C and N in the forest litter – soil organic matter (SOM) continuum are long standing questions central to terrestrial science. Managed forest plantations provide the structure to ask: do forest species, their litters and silvicultural treatments affect the site C balance differentially? And are these differences related to utilization or preservation of litter substrates? To address these questions Currie-point Pyrolysis-Gas Chromotography/Mass Spectrometry-Isotope Ratio Mass Spectrometry (PY-GC/MS-IRMS) and a replicated in-situ forestry experiment are employed to track the fate of biomolecules labeled with 13C and 15N liberated from forest litters to soil after 6 years in-situ. Six experimental treatments of individual litters (4-pine and ceanothous either labeled with 13C or unlabeled control) and litter mixtures (2-13C pine-15N ceanothous or visa versa) supply a structure to clarify litter quality affects on soil C dynamics. Findings from initial soil incubation and one year in-situ studies show that individual and mixed litters had very different affect on C and N mineralization rates and C stabilization of existing soil C and newly added substrates. The pine only treatment had greater CO2 evolution, DOC production and increased mineralization of existing SOM. Mixed litters showed less CO2, DOC and indicated increased stabilization of new substrate C to SOM. This experiment and PY-GC/MS-IRMS method enable classification and tracking of individual compounds and functional groups (sugars, simple alcanes, aromatic compounds) by analyzing undecomposed litter, 6yr decomposed litters and SOM through three soil depth (0-5. 5-15 and 15-30 cm). Sample analysis has begun with preliminary PY-GC/MS-IRMS results developed over the summer and fall of this year for this poster presentation. Tracking compounds will supply the resolution to clarify C and N dynamics and enhance our understanding of broad ecological questions and those more specific to management, vegetation and SOM.