Long-term peat accumulation in temperate forested peatlands (Thuja occidentalis swamps) in the Great Lakes region of North America

Document Type

Article

Publication Date

1-1-2016

Abstract

© 2016 International Mire Conservation Group and International Peat Society. Peatlands are being mapped globally because they are one of the largest pools of terrestrial carbon (C). Most inventories of C have been conducted in northern Sphagnum dominated peatlands or tropical peatlands. Northern white-cedar (cedar, Thuja occidentalis L.) peatlands are amongst the most common peatland types in the Great Lakes Region of North America, yet there is no information on their C pool sizes or rates of C accumulation. Therefore, the main objectives of this study were to determine: 1) the ages of cedar peatlands; 2) the amount of C stored in the peat profile; and 3) the apparent long-term rate of C accumulation. We sampled 14 cedar peatland sites across northern Minnesota and the Upper Peninsula of Michigan, USA. Cedar peat was found to be derived mostly from wood and to have an average thickness of 1.12 m (range 0.3–3.25 m). Basal dates indicated that cedar peatlands were initiated between 1,970 and 8,590 years ago, and they appear to have been continuously occupied by cedar. Long-term apparent rates of C accumulation (LARCA) ranged from a low of 6.4 g C m-2 yr-1 to a high of 39.7 g C m-2 yr-1, averaging 17.5 g C m-2yr-1. Cedar peatlands tend to be shallower than Sphagnum peatlands in the region but, due to their higher bulk density (average 0.16 g cm-3), they contain high amounts of C with our sites averaging ~80 kg C m-2. Thus, they represent a regionally important pool of C.

Publication Title

Mires and Peat

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