/ Practically no information exists on the impact of human trampling on tropical rain forest vegetation. We studied three trails with varying periods of use and recovery in a tropical rain forest in Costa Rica. Human impact on trailside plants was curvilinearly related to use, as found by other workers in temperate zone vegetation. Recovery in a period of two years and eight months had been rapid, and herbs and seedlings were more abundant along the recovering trail than in undisturbed forest. The results imply that a shifting mosaic of trails, analogous to the mosaic created by light gaps, may be the best management technique to minimize the impact of human visitors in tropical rain forests.Although the literature on the impact of truman trampling on the vegetation and soils along trails is substantial (Kuss and Graefe 1985, Kuss 1986, Cole and Schreiner 1981, none of the hundreds of studies deal with tropical rain forests. Nearly all the published papers were done in the temperate zone, especially in the western United States. Of 348 papers on the subject reviewed by Cole and Schreiner in 1981, every single one came from a north-temperate-zone country, and since then only two have been added from tropical or subtropical regions: the study of Liddle and Thyer (1986) in subtropical eucalyptus forest in Australia, and the work of Jim (1987) on the parks of Hong Kong.With the development of ecotourism leading to in-