E-mail : francois.girard.4@ulaval.ca

Origin and distribution of spruce lichen woodlands within the commercial boreal forest
 
Supervisor : Serge Payette
Co-supervisor : Réjean Gagnon, Université du Québec à Chicoutimi

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The boreal forest occupies the majority of the forested region of Québec and can be divided into three zones: the forest tundra, the open forest, and the closed forest. The open forest zone is comprised primarily of spruce lichen woodlands located on well-drained podzolic soils. The forest tundra zone contains the northernmost spruce lichen woodlands and extends up to the northern tree limit. The closed forest zone is characterized by a spruce-moss forest with a continuous arborescent cover. The occasional patche of open forest (spruce lichen woodlands) can, however be found within the closed forest zone. These open environments possess a tree density < 40% of the total cover and are characterized by a lichen ground cover (Cladina and Cladonia species) and ericaceous shrubs (Kalmia, Vaccinium, and Rhododendron). These open areas are considered to be fragile and unproductive, and thus silvaculture practises are not permitted. Recent research, however, has shown that some of these open areas within the commercial boreal forest were once closed black spruce forests that transformed into open forests as a result of successive disturbances (e.g., fire, insect epidemics, outbreaks). In the closed forest zone, where most forestry activities occur, the area of the closed forests is gradually being reduced while that of the open forest areas increases. The dynamics of these forests as a function of latitude has yet to be explained. This project aims to better understand the spatial distribution and the mechanisms that create the spruce lichen woodlands. The principal objectives of this project are: i, to evaluate the spatial distribution of the spruce lichen woodland/spruce-moss forest ratio along a latitudinal gradient extending from the southern limit of the spruce lichen woodlands to the northern limit of the closed forest zone, ii, to determine the origin of the closed and open forests along the gradient, iii, to determine the regeneration potentials of the open forests along the gradient, iv, to identify the disturbance factors responsible for the state of the spruce lichen woodlands, and v, to create an index of stability and resilience for the closed forests along the latitudinal gradient in regards to both natural and anthropogenic disturbances.

Publications

Girard, F., Payette, S., Gagnon, R. 2009. Origin of the lichen-spruce woodland in the closed-crown forest zone in eastern Canada. Global Ecology and Biogeography, 18: 291-303.

Girard, F., Payette, S., Gagnon, R. 2008. Rapid expansion of lichen woodlands within the closed-crown boreal forest zone over the last 50 years caused by stand disturbances in Eastern Canada. Journal of Biogeography, 35: 529-537.