Geographic variation in young red maple grown in north central United States.
Seedlings, from seed collected from 51 natural stands of Acer rubrum in the eastern states of the USA and Canada, were established in plantations in Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin, USA, and evaluated for several characters five years after sowing. Significant differences in height between seed lots were observed in all plantations, the tallest trees being those from seed collected from the north-central and east-central portions of the species range. Seed collected in New York, Michigan, Wisconsin and areas further north resulted in trees with the most intense leaf coloration in autumn; these trees also had medium to straight stem form. Trees from seed of more southerly provenance tended to have a crooked stem form. This is considered to result from susceptibility to damage of the growing points by cold conditions in winter.