Planting trees in the Aleutians

摘要

From Bering's expeditions to present time, naturalists, botanists and foresters have pondered the treeless landscape of the Aleutians. In his "Journal of a Voyage with Bering 1741-1742," Georg Wilhelm Steller, the first European explorer and naturalist to describe the coastal flora and fauna of northwest America, attributed the absence of woodland vegetation in the Aleutians to several factors. These included the northeast-southwest orientation of the islands, their disproportionate length relativeto width, the north-south openness (exposure) of the lands to extreme storms, and the cooling effects of wind and wetness (Frost 1988, Golder 1968) (Fig. 1). Nearly a century later, Veniaminov (1840) noted the relatively recent formation of soils and arrival of vegetation in the Aleutians. He concluded that time was a major factor in the arrival and establishment of forests because the vast expanse of oceans between the islands and forested mainland to the northeast slowed the migration of trees. Unfavorable prevailing winds during the autumn also reduce seed dispersal along the southwest coast and offshore islands of the Alaska Peninsula (Fernow 1902), and well-established tundra inhibits tree seedling establishment, also slowing tree migration.