The success of hybrid poplar planting programs depends on the selection of clones with desirable growth properties, matched to specific environmental conditions. Traditionally, tree geneticists have employed early height growth as an indicator of rotation age volume production. This approach was evaluated against selection functions based upon easily measured mensurational and morphological traits. A mixed planting of 12 clones of three Populus species was analyzed during three years of growth. Clonal and moisture regime variation and co-variation were examined for numerous measured and derived traits. A procedure was developed employing canonical correlation analysis to construct selection functions based on multiple mensurational and morphological traits. Results suggest that simple selection functions based upon easily measured traits are superior to early height growth for ranking hybrid poplar clones for total tree volume production. Copyright (C) 1996 published by Elsevier Science Ltd.