Relationship of White Spruce to Lenses of Perennially Frozen Ground, Mount McKinley National Park, Alaska

Résumé

Reports investigations of perennially frozen mounds beneath individual trees growing in silty clay on a terrace of the McKinley River. Climate, vegetation and parent material of the spruce stand are described. The mounds, 2-4 m in diam, contain a frozen lens-shaped core. The permafrost results from lower temperatures under the trees due to less snow cover and a thicker moss layer. A proposed cycle of development and collapse of the tree mounds is outlined.