The elaboration of an assessment method - in economic terms - of the forest capacity to stop soil erosion

摘要

Researches have been carried out in order to set up a method addressing the evaluation of the opportunity cost of having less forest into a watershed. Two procedures have been developed: the first one allows the assessment of the opportunity cost which is being internalized by the forest administration in terms of torrent control works, the latter is being focused on the externalized costs of having damages due to floods likely to occur downstream. The first procedure consists of a regression analysis, having the value of works as regressands, along with the percentage of forest and watershed morphometric features as regressors. The latter procedure breaks down the value of damages per hectare of catchments area according to runoff coefficients and area associated to different land uses, thus allowing for a sensitivity analysis of downstream damages likely to occur whenever the percentage of forest would have been reduced.