| Unconstrained ordination (DCA) on 604 stands of combined vegetation data from independent surveys, including post-fire, post-clear-cut and carefully-logged boreal forest understorey communities, showed primary trends associated with soil nutrient and moisture regimes. Clear-cut stands appeared to represent a change in community/ecosystem characteristics from the pre-logged condition. Understorey vegetation of the carefully logged stands were similar to postfire oligotrophic forests.; Among the 48 carefully-logged stands only, canonical correspondence analysis (CCA) and partial (P)CCA confirmed the primary importance of soil nutrient and moisture conditions. PCCA indicated that the level of canopy retention, the extent of canopy removal, post-harvest herbicide treatment and age since harvest were minor contributors to the overall plant community variability among stands.; Clear-cutting disrupts the forest floor, changes the soil conditions and precipitates community change. Careful-logging, when carried out only in winter, retains the integrity of the organic forest floor. Consequently, no detectable understory plant community change ensues. |
