Many forest communities possess considerable knowledge of the natural resources they use. Such knowledge can potentially inform scientific approaches to management, either as a source of baseline data to fill information gaps that cannot otherwise be addressed or to provide alternative management approaches from which scientists and managers might learn. In general, however, little attention has been given to the relevance of quantitative forms of such knowledge for resource management. Much discussion has focused on the integration of traditional ecological knowledge (TEK) into management, but less attention has been paid to identifying specific areas where it is most useful and where it may be most problematic. We contrasted scientific data with information from TEK in the context of a threat to the sustainable harvesting of a nontimber forest product (NTFP) of livelihood importance in southern India, specifically, a fruit tree infected by mistletoe. The efficiency of deriving information from NTFP harvesters compared to scientific field studies was assessed. We further evaluated the potential of TEK to provide novel solutions to the management problem in question, the degree to which TEK could provide quantitative information, and the biases that might be associated with information derived from TEK. TEK complemented previously gathered ecological data by providing concordant and additional information, but also contradicted some results obtained using a scientific approach. TEK also gave a longer-term perspective with regard to NTFP harvesting patterns. Combining information on historical and current harvesting trends for the NTFP with official data suggests that current assessments of sustainability may be inaccurate and that the use of diverse information sources may provide an effective approach to assessing the status of harvested resources