Northern Research and Demonstration Farm
Fast-growing tree species, such as cottonwood (Populus spp.) and willow (Salix spp.), grow naturally throughout the Midwest, primarily along streams, and are excellent candidates for a new crop to grow on floodable sites. Other species, such as certain hybrid cottonwoods, are well suited to highly erodible lands (HELs). All of these species might be productive on normal agricultural soils. These types of trees can be used to establish plantings that can be harvested in 8 to 10 years and will re-sprout after harvest to produce another crop.
Iowa State University
Mize, Carl, "Tree Biomass Productivity Project" (2003). Iowa State Research Farm Progress Reports. 1526.