The present invention provides chimeric gene constructs for modulating expression and activity of endogenous Auxin Response Factors (ARFs) in plants, especially ARF2 and/or ARF18, and method of employing the chimeric genes to modulate one or more plant phenotypes including modifications to xylem structure and function. The invention is particularly suited to the production of plants having improved pulp or paper milling properties and improved water use efficiency, resistance to water deficit stress, and recovery from water deficit stress.
