For deforestation-avoidance initiatives, uncertainty is especially high regarding the number of
hectares that has been or would be saved by a
given project. The shapes of the probability density curves associated with bene®t per hectare and area of avoided deforestation are expected to be quite dierent: the
curve representing benefit per hectare would be a
bell-shaped normal probability distribution while the corresponding curve for the number of hectares of deforestation avoided would
have a peak at zero to represent a large chance
that nothing would be achieved and a tail on the
upper side extending to very high values.