Poplars genetically modified not to harm air quality grow as well as non-modified trees

Field trials in the Northwest and Southwest show that poplar trees can be genetically modified to reduce negative impacts on air quality while leaving their growth potential virtually unchanged, says an Oregon State University researcher who collaborated on the study.

The findings, published today in the Proceedings of the National Academy of Sciences, are important because poplar plantations cover 9.4 million hectares globally – more than double the land used 15 years ago. Poplars are fast-growing trees that are a source of biofuel and other products including paper, pallets, plywood and furniture frames.

A drawback of poplar plantations is that the trees are also a major producer of isoprene, the key component of natural rubber and a pre-pollutant.

Increases in isoprene negatively affect regional air quality and also unbalance the global energy budget by leading to higher levels of atmospheric aerosol production, more ozone in the air and longer methane life. Ozone and methane are greenhouse gases, and ozone is also a respiratory irritant. Poplar and other trees including oak, eucalyptus and conifers produce isoprene in their leaves in response to climate stress such as high temperatures.

A research collaboration led by scientists at the University of Arizona, the Institute of Biochemical Plant Pathology in Germany, Portland State University and OSU genetically modified poplars not to produce isoprene, then tested them in three-year trials at plantations in Oregon and Arizona.