courriel :

Impact of forest cover on permafrost of wooded palsas, Boniface River area, northern Quebec.

Direction : Serge Payette


Palsas are peat or mineral mounds having a permafrost core. Palsas are widespread in the circumpolar discontinuous permafrost zone. Wooded palsas are periglacial features which have not been extensively studied. This study takes place in the Boniface River area (57° 45' N; 76° 20' O), where wooded palsas are colonised by arborescent and shrubby black spruce (Picea mariana (Mill.) B.S.P.). The major goal of this research is to assess the impact of the forest cover on the thermal regime by its influence on the snow cover, albedo and solar radiation on the ground. This project aims also to evaluate the role of vegetation and snow cover on thickness of the active layer during summer. To achieve this, data are taken at 7 wooded and non wooded, organic and mineral, palsas. Active layer thickness is measured at regular intervals during summer. At each site, tree height, inferred snow thickness, organic horizon thickness, and vegetation are recorded. Ground and air temperature measurements are recorded all year long by sensors buried at depth of 50 and 100 cm. Snow cover is monitored at one site by pictures taken during winter by a solar powered photographic system.