This study, located in the Itcha - Ilgachuz area of the west Chilcotin Plateau, is part of a research program designed to develop and test silvicultural systems that will maintain caribou winter range while allowing some level of timber harvesting. An important aspect of such silvicultural systems is the maintenance of as much terrestrial forage lichen as possible. Past studies have indicated that lichens in clearcuts after 30 years have not returned to preharvest abundance levels. In this project, one uncut control and three harvest treatments were applied: 30% removal (group selection); 70% removal (clearcutting with small group retention); and 70% removal (clearcutting with large island retention). Three years after harvesting, the two 70% volume removal treatment units had higher levels of lichen mortality and lower forage lichen abundance than did the 30% removal and the uncut control area. Controlling slash build-up proved to be critical to the maintenance of forage lichen abundance: plots with more than 50% slash cover had 85% less forage lichen than plots with no slash loading. Lichen species richness was lowest in plots in the clearcut with large islands. While clearcutting greatly reduced forage lichens, reserve islands provided some lichen habitat. These tree islands may serve as dispersal sources from which the new surrounding forest can be inoculated with lichen propagules. These islands can also provide partial shading for lichens growing in clearcuts immediately adjacent to the reserve.
Working Paper 56 (382 KB)
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Updated July 24, 2015