Forest dynamics in relation to multi-decadal late-Holocene climatic variability, eastern Ontario, Canada

Pollen profiles from two lakes, Tawny Pond (44°48′59″N, 77°10′54″W, 276 m) and Stoll Lake (44°58′16″N, 77°17′22″W,303 m) in Addington Highlands, eastern Ontario, Canada were analyzed to determine the effects of late-Holocene climate change and European settlement on eastern Ontario's forests. Both lakes were analyzed at high temporal resolution and record vegetation dynamics over the last 1000 years. Throughout the past 1000 years, Pinus, Tsuga, Betula, Quercus, Acer and Fagus were the dominant taxa in the pollen record. From 950-1550 AD the forest was dominated by Tsuga, Fagus and Acer. Between 1550 and 1730 AD Pinus and boreal tree species became more abundant and/or had increased relative pollen production. Low pollen influx to the sediment, high values of Pinus and relatively low values of Tsuga and hardwoods between 1730 and 1870 AD suggest colder temperatures. Since 1870 AD, herbaceous plants (weeds) increased in abundance, whereas softwoods decreased and hardwoods increased, due to landscape changes associated with European settlement. A comparison of the temperature reconstruction based on the pollen assemblages and the Toronto and Ottawa climate records shows a close correspondence, suggesting pollen records can record decadal-scale climate fluctuations.