E-mail : sarah.auger.1@ulaval.ca

Structural dynamics of an ancient spruce lichen woodland at the northern forest limit
Supervisor : Serge Payette 



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At the end of the last glaciation, after the glaciers and the Tyrrell Sea retreated, black spruce (Picea mariana) forests colonized northern Québec. Some of these forests, which are currently found at the tree limit, have never been affected by fire, and have maintained themselves vegetatively for at least 1000 to 2000 years. These forests are therefore considered ancient. The principal goal of this research project is to study the temporal variations in the age and height structures of black spruce along with soil dynamics in an ancient spruce lichen woodland at the northern forest limit (Boniface River region; 57° 45' N ; 76° 20' W). The manner in which the trees establish (through cloning or seed germination), use and modify soils, and the time periods for which they can maintain themselves, either in clonal or individual form, will be studied. A paleoecological study of the environment, including the dendrochronological analysis of subfossil wood and the radiocarbon dating of soils and wood charcoal, will be conducted in order to determine how the forest has evolved since its establishment and determine if it is in equilibrium with its environment. The influence of certain ecological factors, including snowpacks, windfalls, and fire, on the forest will also be evaluated. A fine spatial analysis will be conducted within a quadrant established within the forest. All living and dead black spruce will be mapped, described, and measured. Only dead individuals will be sampled (cut) for dendrochronological analysis in the laboratory. Age structure curves for the forest will then be constructed in order to determine if the forest is in equilibrium with its environment. To describe the soils, several soil pits will be dug systematically within the quadrant and numerous soil samples will be obtained in order to evaluate soil characteristics in the laboratory. Finally, the data will be analyze using statistical tests in order to determine the different spatial correlations between the soil and the vegetation.

Publication

Auger, S. & S. Payette, 2010. Four millennia of woodland structure and dynamics at the arctic treeline of eastern Canada. Ecology, 91:1367-1379.