RATES OF MIGRATION

Rates of migration also vary directly between species (E.C. Pielou, 1991).

White Pine migrates at 300 to 350 m/yr.

Hemlock migrates at 200 to 250 m/yr.

Maple migrates at 200 m/yr.

Chestnut migrates at 100 m/yr.

The first three all have winged seeds, and as a result they tend to migrate faster. This is not always the case though, it is highly dependent on wind speed and strength.

EXAMPLE: The migration of white spruce varied in speed across North America. In the east it shows a steady pace of 300 m/year but in the west there is evidence of a sudden "sprint" 2000 km north to the Beauford Sea, ten times faster than in the east. This advance took place approximately 9k B.P when the Laurentide ice sheet lay over what is now Hudson's Bay. It is thought that fierce southerly wind blowing clockwise around the sheet resulted in the rapid dispersal of the winged seeds of white spruce (E.C. Pielou, 1991).