Influences of riparian logging and in-stream large wood removal on pool habitat and salmonid density and biomass: a meta-analysis

We conducted a meta-analysis using data from 37 studies to assess whether the effects of streamside clear-cut logging on large wood (LW), pool size and number, and summertime salmonid density and standing crop biomass were influenced by stream size and gradient, time since logging was last conducted (1-100 years), and removal of in-stream LW. Age-specific (age 0 (fry) and age 1 + (juveniles)) and species-specific (coho salmon (Oncorhynchus kisutch), cutthroat trout (Oncorhynchus clarki), and steelhead and rainbow trout (Oncorhynchus mykiss)) comparisons were also made. The majority of studies reported negative postlogging responses for LW and pool habitat but positive responses for salmonid density and biomass, with the greatest reductions in all variables generally associated with a thorough removal of in-stream LW. The magnitude of postlogging responses was largely independent of stream size, gradient, and time since logging last occurred. In terms of density and biomass, juveniles were more negatively affected by logging than fry. Of the surveyed species, steelhead trout appeared to be most resilient to riparian logging. Within the time frame covered by the analyses, streams whose riparian zones have been logged may be able to sustain salmonid populations (and even exceed preharvest levels) as long as rigorous removal of LW is not undertaken.