1. G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 500 10th Street NW, Atlanta, GA 30332-0620, USA
2. Renewable Bioproducts Institute, Georgia Institute of Technology, 500 10th Street NW, Atlanta, GA 30332-0620, USA
3. Department of Forest Genetics and Plant Physiology, Umea Plant Science Center (UPSC), Swedish University of Agricultural Science (SLU), 901-83 Umea, Sweden