Poplars and willows have been used for environmental applications throughout human history. There is archaeological and historical evidence of their use for cooking, heating, and shelter in ancient times in China and the Middle East. Native Americans used them in riparian zones for irrigation over 2000 years ago. Explorers in North America also used them for fuel and shelter, and pioneers used them for windbreaks and shelterbelts as they settled the West. In the 17th century European settlers admired native North American poplar and willow and took specimens back to Europe for their gardens. Spontaneous hybrids arose with European poplar and willow that proved handsome and productive thereby prompting breeding efforts. Soon American and Canadian geneticists patterned their breeding programs after European breeding successes. Poplar and willow are valued for traits including wide adaptation, rapid growth rate, cross-ability, deep rooting, ease of rooting, and large leaf areas that allow them to take up large quantities of water and nutrients. The “Oil Embargo” of 1973 led to an explosion of basic research by worldwide organizations in the use of poplar and willow for bioenergy. This research included multiple breeding programs and the advent of short rotation woody crops. During the environmental movement of the 1980’s, researchers’ efforts turned to environmental applications of poplar and willow. The interest in using “green technology” led to the emergence of phytoremediation (phyto) in the early 1990’s; the science of using plants for cleaning up contaminated soils and water. Poplar and willow are used in multiple phyto applications including buffers, vegetative filters, in situ plantings and vegetative landfill caps. There are promising opportunities for using poplar and willow for wastewater re-use, riparian buffers, landfill leachate recycling, animal confinements, carbon sequestration and urban amenities. Lessons can be learned from the long history of poplar and willow use for environmental applications. Bioenergy opportunities have fluctuated greatly since 1973, reflecting oil prices and production costs. But, new biotechnologies have recently been discovered that will expand our opportunities for environmental applications of poplar and willow. Many challenges remain including the costs of biomass products, market values of those products, lack of funding, climate change and resulting disease/insect problems, regulatory issues, public policies and politics, GMO issues, and public awareness problems.
This project is supported by an Agriculture and Food Research Initiative Competitive Grant no. 2011-68005-30407 from the USDA National Institute of Food and Agriculture (NIFA).