The Pachistima and Phyllodoce types, which were 

 dominated by shrubs, generally experienced interme- 

 diate levels of impact. Of these two, the Pachistima 

 type, which had taller and stouter shrubs, was sub- 

 stantially more resistant. These shrub types, and 

 Phyllodoce in particular, were initially the most resis- 

 tant to height reduction. They were not very resiUent, 

 however. One year after trampling, the Phyllodoce 

 type clearly was the most heavily impacted of all four 

 vegetation types. Aside from an increase in species 



richness, little recovery occurred over the year. The 

 Pachistima type continued to show substantial cover 

 loss and an evident trail on the 500-pass lanes, but 

 vegetation height, species richness, and species com- 

 position were close to the original conditions. 



Individual Species Responses 



Relative cover could be calculated for nine species 

 of vascular plants and for mosses as a group (fig. 6). 



Carex nigricans Mosses Pachistima myrsinites 



200 500 700 200 500 200 



Phyllodoce empetriformis Vaccinium membranaceum Mitella breweri 



200 500 200 500 200 500 200 500 



Number of Passes 



Figure 6 — Relative cover after trampling and after 1 year of recovery for abundant species in four 

 vegetation types in Washington's Cascade Mountains. 



12 



