Climate Science

The Way They Were

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Science  27 Apr 2012:
Vol. 336, Issue 6080, pp. 393
DOI: 10.1126/science.336.6080.393-a
CREDIT: ISTOCKPHOTO.COM

During much of the Eocene, from about 55 to 45 million years ago, vast conifer forests existed north of the Arctic Circle where no such vegetation exists today. Some paleobotanical studies have led to suggestions that the forests of eastern Asia are a good modern analog for those ancient woods, based on the similarity of tree types. However, more recent studies of environmental conditions such as mean annual precipitation and productivity in the Eocene have led others to conclude that the Arctic forests were more like those of the modern Pacific Northwest. Schubert et al. present reconstructions of the seasonality of paleoprecipitation, based on high-resolution intra-ring carbon isotope measurements of fossil wood, to show that the Eocene Arctic forests experienced around three times more precipitation during summer than during winter, unlike in the Pacific Northwest, where summer precipitation is much less abundant than winter precipitation. Therefore, the temperate forests of eastern Asia probably are the best modern analog for the Eocene Arctic forests.

Geology 10.1130/G32856.1 (2012).

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