The difficulty involved in performing an agronomic diagnosis of a tree crop is obtaining an accurate picture of current and past cultivation practices, to be able to assess their impacts on the agro-ecosystem as well as on sustainability. As latex harvesting involves tapping the bark, which leaves scars on the trunk, we hypothesised that these morphological traces would be good indicators of current and past practices and would thus enable a diagnosis based on the economic lifespan of plantation. To this end, we formalized a tapping panel diagnosis that involved reproducing the scars on tapping panel diagrams, and analysing them using two indicators: the amount of virgin bark consumed and the number of tapping years that remained. We characterised eight tapping management systems reflecting different levels of tapping intensity. Assessment of the respective share of each tapping practice on virgin bark consumption revealed major effects of tapping frequency and of shaving thickness. We showed that, used as a decision support tool, the tapping panel diagnosis can increase remaining tapping years. To conclude, the tapping panel diagnosis will be a useful support for the participatory development of innovating tapping management schemes involving both technicians and smallholders.