Trampling Effects on Vegetation of the Trail Corridors of North Rocky Mountain Forests

Abstract

The management of trails should be based on knowledge of the effects of humans on them; most of the available information has been reviewed by Speight (1973), Stankey & Lime (1973), and Liddle (1975). Observations of existing trails suggest the following conclusions. (1) Vegetation cover is reduced by trampling and some plants are more resistant to trampling than others (Speight 1973; Liddle 1975; Dale & Weaver 1974; Davidson & Fox 1974). (2) Trail width increases linearly with increasing slope, wetness, roughness and the logarithm of the number of users (Bayfield 1973; Dale & Weaver 1974), but decreases linearly with the logarithm of the roughness of trailside vegetation and terrain (Bayfield 1973). Vegetation more than 2 m from the edge of a trail is often little effected (Dale & Weaver 1974). (3) Trail depths depend on compaction and erosion and therefore on climate, vegetation type, soil and substrate type, slope, and type of user (Helgath 1975; Dale & Weaver 1974). (4) Soil compaction is usually greater, i.e. bulk densities average 02-06 g cm-3 greater, in trampled areas than in untrampled areas. Several experimental studies .have shown the quantitative effects of wear on vegetation (Bell & Bliss 1973; Liddle 1975; Liddle & Greig-Smith 1975; Rogova 1976) but there has been no experimental comparison of the effects of different modes of trail travel. The experiments reported below compare the effects of hiker, motorcycle, and horse trampling on level and sloping sites in both a meadow and a forest with a dwarf shrub understorey.