An Early Tree-line Experiment by a Wilderness Advocate : Bob Marshall's Legacy in the Brooks Range, Alaska

... Already in the 1930s, Bob Marshall was working on the question of the tree line and tree-line advance in the Koyukuk country of northern Alaska's Brooks Range. His theory was that trees did not have enough time after the last glaciation to occupy their potential growth range. The seed dispersal mechanism, in his view, prevented a fast advance of white spruce into tundra. He calculated the advancement rate of the northern tree line at 1 km per 150 years .... This was, as we now know, a strong underestimation. To test his hypothesis, Marshall sowed white spruce seeds north of the tree line in three separate watersheds (Grizzly Creek, Barrenland Creek, and Kinnorutin Creek). Here we present the rediscovery in 2001 of one of his plots - Barrenland Creek. ...