Canadian Forest Service Publications
Lichen conservation in heavily managed boreal forests. 2013. McMullin, R.T.; Thompson, I.D.; Newmaster, S.G. Conservation Biology 27(5):1020-1030.
Available from: Great Lakes Forestry Centre
Catalog ID: 34929
CFS Availability: PDF (request by e-mail)
Available from the Journal's Web site. †
† This site may require a fee
Lichens are an important component of the boreal forest, where they are long lived, tend to accumulate in older stands, and are a major food source for the threatened woodland caribou (Rangifer tarandus caribou). To be fully sustainable, silvicultural practices in the boreal forest must include the conservation of ecological integrity. Dominant forest management practices, however, have short-term negative effects on lichen diversity, particularly the application of herbicides. To better understand the long-term effects of forest management, we examined lichen regeneration in 35 mixed black spruce (Picea mariana) and jack pine (Pinus banksiana) forest stands across northern Ontario to determine recovery following logging and postharvest silvicultural practices. Our forest stands were 25–40 years old and had undergone 3 common sivilcultural treatments that included harvested and planted; harvested, planted, and treated with N-[phosphonomethyl] glycine (glyphosate); and harvested, planted, and treated with 2,4-dichlorophenoxyacetic acid (2,4-D). Forest stands with herbicide treatments had lower lichen biomass and higher beta and gamma diversity than planted stands that were not treated chemically or control stands. In northwestern Ontario, planted stands that were not treated chemically had significantly greater (p < 0.05) alpha diversity than stands treated with herbicides or control stands. Our results show that common silvicultural practices do not emulate natural disturbances caused by wildfires in the boreal forest for the lichen community. We suggest a reduction in the amount of chemical application be considered in areas where lichen biomass is likely to be high and where the recovery of woodland caribou is an objective.
Plain Language Summary
Lichens are a major food source for the threatened woodland caribou. Forest management practices, particularly herbicide application, can have a negative effect on lichen diversity. We examined lichen regeneration in 35 mixed black spruce and jack pine forest stands in northern Ontario. We compared naturally regenerated stands with planted stands 25-40 years old. Some planted stands had also been treated with 2,4-D or glyphosate herbicide. Our analysis showed that stands treated with herbicide had lower lichen biomass. In northwestern Ontario, these stands also had a lower diversity of lichen species. Our results show that common silvicultural practices do not emulate natural disturbances caused by wildfires in the boreal forest for the lichen community. We suggest a reduction in the use of chemical herbicides be considered in areas where the recovery of woodland caribou is an objective and where lichen biomass is likely to be high.