Biomass productivity improvement for eastern cottonwood

Abstract

Eastern cottonwood (Populus deltoides Marsh.) is grown in plantations by MeadWestvaco for use at its Wickliffe Kentucky Fine Papers Mill1. Genetic and productivity research over the past two decades have led to significant increases in biomass yield while reducing production costs. Initially, genetic research identified fast growing clones for sites along the Mississippi River alluvial floodplain near Wickliffe, Kentucky. Clone recommendations are refined continuously through testing, and we add new clones to the program to broaden the genetic base. Breeding and selection allow us to combine traits important to the paper making process in select clones. In 1996, a fiber farm was established, and additional genetic testing was needed to develop clones for this radically different production system. Biotechnological advances such as the use of genetic markers and transformation have proven their value for cottonwood, but regulatory approval is needed to commercialize this technology. Over the past five years, our plantation productivity research has reduced fiber production costs by defining optimal management regimes for alluvial and fiber farm sites. As research identifies the best herbicides, rates, and application times, chemical weed control use is increasing and gradually substituted for mechanical cultivation. Studies on planting dates and cutting length showed that successful plantations can be established in July to avoid spring floods, and long cuttings grow faster than shorter ones. Water, nutrient, and spacing studies indicated that initial fiber farm management regimes could be improved substantially. In addition, research on cottonwood leaf beetle showed that damage was minimized during the critical plantation establishment phase using an insecticide that is new to forestry.