Among other important factors, vegetation cover strongly affects the hydrological processes in mountain catchments. In this paper, we present the results of field infiltration measurements at the location of various vegetation covers, together with an estimation of the infiltration characteristics of a small mountain forest catchment. Measured steady infiltration rate values were extrapolated on the basis of the dominant plant species distribution in the catchment. We determined which plant species are dominant, and infiltration tests were carried out where these species were located in selected sites in the catchment. The characteristic steady infiltration rates were averaged for each dominant vegetation species. The percentages of dominant plant species were determined for established points placed in a regular network throughout the basin. An extrapolation of the directly measured infiltration values to these established points was calculated using (1) percentages of the dominant plant species determined at these points, and (2) characteristic infiltration rates averaged for these species. An infiltration map was created from the infiltration values calculated for the established points.