Effects of partial cutting on forage lichens for caribou in a subalpine forest: the Pinkerton Mountain silvicultural system trial revisited 10 years after harvesting

"Partial cutting systems have often been proposed as a means of maintaining canopy lichen abundance and diversity in managed forests. However, most assessments of the effectiveness of specific harvest practices in maintain canopy lichens are based on immediate post-harvest measurements. Fewer assessments extend beyond the immediate 2-3 year post-harvest period. We anticipate that changes in lichen community composition will occur for many decades after harvesting, as lichens respond over time to changes in canopy microclimate and substrate availability. We can now report on the response of canopy lichen communities 10 years after partial cutting at Pinkerton Mountain, in B.C.’s central interior, where 30% of the timber volume had been removed in a side-by-side comparison of two partial-cut harvesting treatments: one in which trees were removed in patches, as part of a group selection silvicultural system, and one in which trees were removed singly from throughout the harvest unit, as part of a single tree selection silvicultural system. Our measurements show a shift in canopy lichen genus composition, with the proportion of Bryoria – the preferred winter forage of the red-listed mountain caribou – gradually increasing in relation to Alectoria. However, it will still be many decades before overall forage lichen loading in the partial cut harvest stands approaches that of uncut adjacent old-growth forests. Thus, although partial cut harvesting is an effective strategy for maintaining winter forage for mountain caribou, it cannot substitute for maintaining core habitat in a natural state."