Highly productive polar forests from the Permian of Antarctica

Two stratigraphically closely spaced bedding planes exposed at Lamping Peak in the Upper Buckley Formation, Beardmore Glacier area, Antarctica contain abundant in situ stumps (n = 53, n = 21) and other plant fossils that allow reconstruction of forest structure and biomass of Glossopteris forests that thrived at similar to 75 degrees S paleolatitude in the Permian. Mean trunk diameter is 14 and 25 cm, corresponding to estimated mean maximum heights of 12 and 19 m. Basal areas are 65 and 80 m(2) ha(-1). The above ground biomass was calculated using allometric equations for Ginkgo biloba, yielding biomasses of 147 and 178 Mg ha(-1). Biomass estimates based on comparison with biomass of modern forests with equivalent basal areas are higher (225-400 Mg ha(-1)). The amount of above ground biomass added each year (annual net primary productivity), based on biomass estimates and growth rings in silicified plant material from the Buckley Formation nearby, is poorly constrained, ranging from similar to 100-2000 g m(-2) yr(-1). Compared to modern forests at all latitudes, the Permian forests have high basal areas and high biomass, exceeded in both only by forests of the U.S. Pacific northwest and Sequoia forests. The estimated range of productivity (ANPP) is within that of many very productive modem forests. The Lamping Peak forests' basal areas and calculated biomass are also larger than younger high paleolatitude fossil forests except for Arctic Cenozoic forests. The presence of these highly productive fossil forests at high paleolatitude is consistent with hothouse conditions during the Late Permian, prior to the eruption of the Siberian flood basalts. (C) 2015 Elsevier B.V. All rights reserved.