T252 Lakes of the World through Time and Space II

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

RECONSTRUCTED HIGH-RESOLUTION FOREST DYNAMICS, CLIMATE AND HUMAN IMPACTS FROM ÉTANG FER-DE-LANCE, SOUTHEASTERN QUÉBEC, CANADA, FOR THE LAST TWO MILLENNIA

Paper number: T252-8
Program: Technical Sessions
Time: 11:35 AM – 11:50 AM

Authors

Abstract

We used a high-resolution lacustrine pollen record from Étang Fer-de-Lance (45°21'21.9"N, 72°13'35.3"W), southern Québec, Canada, together with microcharcoal, to infer forest dynamics, climate and human impacts over the past 2300 years. The lake is located in the sugar maple-basswood domain of the Northern Temperate Forest. We found that Fagus grandifolia (American beech) and Tsuga canadensis (eastern hemlock) significantly declined over the past 700 years. Over the last millennium, Picea glauca (white spruce), Picea mariana/rubens (black and red spruce), and Pinus strobus (eastern white pine) significantly increased. Using the modern analog technique (MAT), we found a warm and dry first millennium AD, a somewhat less warm and less dry Medieval Climate Anomaly, and a cold and wet Little Ice Age. The signal for human modification of the landscape first appeared at ~AD 1550-1650 as increases in Ambrosia (ragweed) and Poaceae (grasses) from Indigenous agriculture. The signal of European settler landscape modification appeared at ~AD 1770 as the beginning of a steep, “classic” Ambrosia rise. It intensified over the subsequent 250 years as further increases in non-arboreal pollen taxa and early successional Acer (maple) species. Microcharcoal analysis showed that fire is a natural part of the sugar maple-basswood domain with a mean fire return interval of 515 years.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-359028

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