Date of this Version
Cellulosic Energy Cropping Systems, First Edition. Edited by Douglas L. Karlen.
Populus consists of 25–35 species and among them hybridization is common. The genus itself has a large genetic diversity with some species growing 50 m tall with trunks of up to 2.5 m in diameter. All Populus species from family Saliceae are common in temperate climate zones but they are limited in tropical zones because the maximum temperature they can tolerate is approximately 30◦C. Among the various species, Populus alba grows primarily in southern and central Europe, P. tremula in Europe and Asia (mainly in India), and P. tremuloides in North America with their northern border being Alaska. There are some reports concerning Populus deltoides growing in India , and although some Populus genotypes can be successfully grown on saline-sodic and alkaline soils, some tested clones could not survive those soil and climatic conditions in Uttar Pradesh province. In an age of globalization there is an increasing tendency for farmers, foresters, and owners of recreation areas to introduce different poplar species in non-native environments. Therefore, numerous Populus species are often found outside their natural borders. In Europe, for example, the most frequently grown poplar is hybrid Populus × euroamericana (Populus deltoides × P. nigra).