Environmental applications of poplars and willows
Poplars and willows have been planted for environmental purposes for millennia. There are reports that poplars were planted to improve the human environment 4000 years ago in the third dynasty of Ur, for streamside stabilization 2000 years ago in what is now the south-western USA by native North Americans and for urban amenities by the early Chinese dynasties (see Chapter 1, this volume). Early settlers in Europe and North America planted poplars and willows (and other species) to provide shelter and to protect crops. There were also a significant number of linear plantings of poplars in cities for protection, visual screens and aesthetics (FAO, 19 80; Isebrands and Karnosky, 2001).