The impact of forest paths upon adjacent vegetation: effects of the path surfacing material on the species composition and soil compaction

This paper describes the vegetation which develops around forest paths (closed to public motor vehicles) in a 4383 ha-beech forest in central Belgium. The main purposes of these investigations were to analyse how far into the forest stands, paths have an influence on the surrounding plant species composition; and to acquire more specific information on the particular effect of some types of surfacing materials. The results show that forest paths have a significant effect on the surrounding plant assemblages. Some species are significantly associated with one particular type of surfacing material. Globally, the presence of a path results in an increase in the number of ruderal species, disturbance indicators, nitrogen-demanding species and indicators of basic conditions. Eutrophication and pH increase, as inferred from the plant composition, are perceptible up to a minimum distance of 10 m from the path. The consequences for long-term conservation of the woodland flora are discussed.