Most study sites are situated within the Lake
Duparquet Research and Teaching Forest, located
south of Lake Abitibi (48”30’N, 79”2O’W, altitude
about 300 m>, close to the Quebec-Ontario border
(Fig. 1). The area is characterized by the presence of
extensive clay deposits originating from the
proglacial Lake Barlow-Ojibway (Veillette, 1994)
and low rocky hills, the bases of which are covered
with reworked tills (Bergeron et al., 1983). The
climate is cold (annual average temperature 0.6”C)
and continental (annual average precipitation 822.7
mm). The average frost-free period is 64 days although
frosts may occur any time during the growing
season (Anonymous, 1982).