White Spruce above and Beyond Treeline in the Arrigetch Peaks Region, Brooks Range, Alaska

White spruce trees occur in the Arrigetch Creek valley and its tributaries at great distances above and beyond current treeline, which is at 760 m elevation. The highest tree found is at 1465 m elevation on a south-facing limestone slope. Trees also occur up to 5.0 km beyond treeline on granitic parent rock. These trees appear to occur at the highest elevation north of the Arctic Circle in North America and include some of the highest trees in Alaska.Key words: Brooks Range, Alaska, treeline, white spruce, seed dispersal