Soil nutrient differences between two krummholz-form tree species and adjacent alpine tundra

Above treeline at Goliath Peak, Colorado, Pinus aristata (bristlecone pine) and Picea engelmannii (Engelmann spruce) grow as krummholz tree forms. Due to the harsh alpine climate, these trees are dwarfed in size (approximatel y 0.5 to 3.0 m tall) and root along a horizontal stem. Soil nutrients, incl uding carbon, nitrogen, and phosphorus fractions were examined to 10-cm dep th beneath P. aristata krummholz and P. engelmannii krummholz, as well as f rom adjacent, undisturbed alpine soils. Plant available phosphorus was high er under P. engelmannii than P. aristata, suggesting that although these tw o species exist in the same environment, they have a different effect on th e availability of labile soil phosphorus. Mineral soils under P. aristata w ere not significantly different than under P. engelmannii for total carbon, total nitrogen, and total phosphorus. Soil phosphorus differences are impo rtant in this ecosystem because of the proposed P limitation in some alpine ecosystems. (C) 2001 Elsevier Science B.V. All rights reserved.