Fast growing hybrid poplars---the product of selective breeding of native cottonwoods---are being widely planted by agriculture to supplement the diminishing supply of natural hardwoods. As effective biofilters, these trees are also being increasingly used to treat agricultural runoff and municipal wastewaters. Given such uses, the cultivation of hybrid poplars in floodplain habitats is expected to increase significantly. This report discusses the major biological distinctions between hybrid poplars and native cottonwoods, and explores some of the potential management issues associated with their cultivation near riparian corridors. In general, despite the widespread planting of non-native poplars throughout the West, this review finds that their influence on the genetics and ecology of native cottonwoods has been limited. Likewise, their overall impact on groundwater and streamflows is found to be comparable to other tree species and agricultural crops. Recommendations for further reducing any impacts and for improving the habitat values of such tree crop are provided, along with recommendations for future research. The report also emphasizes the critical role of native cottonwoods in the structure and function of riparian corridors, and urges the conservation and study of remnant stands of these important trees.

"EPA 910-R-99-002" "EPA Project Manager: Thomas E. Wilson." "March, 1999"