Holocene history of forest trees in southern Ontario.

Three new Holocene pollen percentage and accumulation rate diagrams for S Ontario are presented. In the earliest Holocene, the forests were dominated by Picea, which was replaced by first Pinus banksiana - resinosa and then Pinus strobus. In extreme S Ontario, Pinus strobus was replaced by Acer saccharum and Fagus grandifolia, but in the area east of Georgian Bay, Tsuga canadensis became the dominant, and near Mattawa, Betula (probably lutea). Late Holocene stability of forests is considered to be a function of the lack of taxa better able to compete than those already present. -from Author