Abstract
Measurements of total height and frequency of frost damage on 5-year-old trees demonstrated moderate to large variation associated with seed origin. Total height was measured at three nurseries in Wisconsin and Minnesota. Frost damage was measured at one nursery in central Wisconsin. The tallest seedlings were from eastern provenances. The seedlings least damaged by spring frost were from Wisconsin and Michigan provenances. Periodic measurements of shoot elongation indicated that variation in rate of elongation was the chief determinant of variation in total shoot elongation. Variation in time of shoot growth initiation was one cause of observed variation in frequency of frost damage. Variation among maternal progenies from six populations in Wisconsin and Michigan was similar to variation among range-wide provenances.