Modelling interception loss for two sparse eucalypt and pine forests in central Portugal using reformulated Rutter and Gash analytical models

Gross rainfall, throughfall and stemflow were measured in Eucalyptus globulus Labill, and Pinus pinaster Ait. stands in central Portugal over two and a half years (from January 1992 to July 1994). The results show that the interception loss is higher in the pine stand (17% of gross rainfall) than in the eucalypt stand (11% of gross rainfall). Interception loss was also simulated by the Rutter model and Gash's original analytical model, but both models overestimated the interception loss from these Mediterranean sparse forests by 29-44%. To improve the description of the rainfall interception from sparse forests, the Rutter model was reformulated. This new version of the Rutter model and a previously reformulated version of Gash's analytical model greatly improved the accuracy of the simulation for both forests, resulting in estimates of the interception loss within 3% of the measured values.