Assessment of the Live Tree Retention Targets of the Williamson’s Sapsucker Best Management Practices

Abstract

Best Management Practices (BMPs) for timber harvesting in Endangered Williamson’s Sapsucker Critical Habitat were published in 2014. These established several live tree (>17.5-cm dbh) retention targets in cutblocks (with a minimum of 85 live tree stems per ha (sph) and a maximum of over 225 sph) to maintain suitable habitat of Williamson’s Sapsucker. We first reviewed the rationale for the targets and found them well supportednby analyses of independent datasets. These datasets included locations of nests in cutblocks relative to sph, direct observations of adults foraging from nests, foraging stand preferences based on radio-telemetry, tree densities at nests versus unoccupied sites, and breeding occupancy of cutblocks. Williamson’s Sapsucker avoided stands with <100 sph and >400 sph. Examination of 113 cutblocks approved after 2014 that contained Critical Habitat for Williamson’s Sapsucker found that 62% did not retain even the minimum 85 sph targetsnof the BMPs, largely because application had been voluntary. The live tree retention targets will need to be met by selection harvesting and silvicultural systems at the hectare scale, i.e., not averaged over whole cutblocks, because any portions of cutblocks with <100 sph would be lost habitat that could not be replaced by averaging over portions of the block that may be more densely treed.