Inherent Variations in the Response of Aspen to Frost Damage

Aspen: Ecology and management in the western United States

“…Observing shoot development of 60 aspen clones from 9,800 to 10,200 feet (3,000 m to 3,100 m) in elevation, on a southeast facing slope in northern Colorado, Egeberg (1963) found that more than 3% weeks elapsed between the times the first and last clones flushed out. This wide clonal variation in timing of bud break resulted in clonal differences in susceptibility to frost damage.…”

“…Almost every conceivable combination of morphological and phenological characteristics has been reported' in aspen clones (Cottam 1954, Egeberg 1963, Morgan 1969, Strain 1961. 'Montgomery, D. H. 1957.…”

“…Marked differences in timing of leaf flushing between clones have been observed (Baker 1921, Barnes 1969, Cottam 1954, Egeberg 1963, Strain 1966. The clonal variation does not result entirely from genetic differences between clones; site has a considerable effect on leaf flushing, also.…”

“…The clonal variation does not result entirely from genetic differences between clones; site has a considerable effect on leaf flushing, also. Egeberg (1963) sampled 60 clones on one Colorado hillside. all at similar elevations and facing the same direction.…”

“…This begins just below the leaf buds when they begin to swell. Egeberg (1963) reported twigs killed by 6 days of severe freezing in April, in Colorado. Cayford et al (1959) reported similar frost damage in Canada following 7 days of unseasonably warm April weather which had caused leaf buds to swell.…”