Electron Spin Resonance (ESR) measurements were performed on particle size fractions of high and low humifiedSphagnum fuscumandCarex rostrata. Each peat sample was divided into seven particle size groups, where the size varies between >2.0 andCarexpeat type class and the low humifiedSphagnumpeat, slightly worse with the high humifiedCarexpeat and the high humifiedSphagnumpeat types. Many of the dependent variables were well modeled, and unknown test samples were correctly predicted