The multivarible geographic coordinates and ecological factors were reduced to a single element by using the principle and technology of canonical correlation. Two ecological gradient axes (EGA) were suggested: EGA(CA) and EGA(r²). These two EGA were calculated among twenty provenances of American elm. The average correlation coefficients between the two EGA and six environmental factors were 0.8551 and 0.8604.The multiple correlation coefficients were 0.9998 and 0.9985,respectively All environmental factor...