Tree fodders are important components of ruminant diets in many less developed countries and tannins are an important factor in determining their nutritive value. This paper explores an indigenous knowledge system that relates to the quality of tree fodder used by farmers in Nepal. The results suggest that the knowledge of tree fodder quality possessed by farmers is quite consistent with the information that may be generated from laboratory analyses. Of the 2 distinct indigenous quality scales used, one (obanopan) appeared to relate to digestibility of tree fodder (as predicted by an in vitro test) and the other (posilopan), that was perceived as an indicator of general nutritional quality, may relate to the ability of a tree fodder to promote the supply of protein at the duodenum. However, the relationship between obanopan and in vitro digestibility indicated that Nepalese farmers preferred to feed less digestible fodder. Nepalese farmers keep animals for a range of objectives, not just milk and meat production. Manure production and the need to fill animals at times of feed shortage are also important. This observation highlights the importance of interpreting nutritional information against farmers' objectives for a given set of circumstances.