Accurate modelling of electrical tree growth is dependent upon a physical and chemical understanding of the insulation and degradation processes on the scale of the tree branches. While imaging techniques for the physical elements of tree growth have improved in recent years, those for the chemical regime are lagging behind. In this paper AFM-IR (Atomic Force Microscopy - Infrared Spectroscopy) is applied to a non-conducting tree channel grown in epoxy resin. This provides chemical analysis with a spatial resolution of 50 nm. The distinct chemistries from within buried channels, exposed channels and the epoxy bulk are revealed for the first time.