The importance of incorporating traditional ecological knowledge (TEK) and traditional resource management (TRM) into resource management plans is increasingly recognized, but little quantitative data exists on the ecological and economic implications of these systems. We quantitatively evaluate the TEK and TRM associated with the nontimber forest species, Aechmea magdalenae, in indigenous Chinanteco communities in Mexico. Two TRM systems for A. magdalenae are described and their effects on growth rates of individuals and populations are measured. Simulations using matrix population models combined with yield experiments reveal that one management system is higher yielding and less costly than the other. Thinning and transplanting are two of the most important management practices that enable populations to withstand higher rates of harvest than those predicted in a management plan that was not based on TRM. Quantitative evaluation of Chinanteco TEK is used to discuss how it may be best combined with science in management plans for nontimber forest species.