Genetic and environmental influences on cold hardiness of native and introduced riparian trees

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To explore latitudinal genetic variation in cold hardiness and leaf phenology, we planted a common garden of paired collections of native and introduced riparian trees sampled along a latitudinal gradient. The garden in Fort Collins, Colorado (latitude 40.6°N), included 681 native plains cottonwood (Populus deltoides subsp. monilifera) and introduced saltcedar (Tamarix ramosissima, T. chinensis, and hybrids) collected from 15 sites from 29.2 to 47.6°N in the central United States. In the common garden, both species showed latitudinal variation in fall, but not spring, leaf phenology. This suggests that latitudinal gradient field observations in fall phenology are a result, at least in part, of the inherited variation in the critical photoperiod. Conversely, the latitudinal gradient field observations in spring phenology are largely a plastic response to the temperature gradient. Populations from higher latitudes exhibited earlier bud set and leaf senescence. Cold hardiness varied latitudinally in both fall and spring for both species. Although cottonwood was hardier than saltcedar in midwinter, the reverse was true in late fall and early spring. The latitudinal variation in fall phenology and cold hardiness of saltcedar appears to have developed as a result of multiple introductions of genetically distinct populations, hybridization, and natural selection in the 150 years since introduction.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Genetic and environmental influences on cold hardiness of native and introduced riparian trees
Year Published 2012
Language English
Publisher USDA Forest Service, Rocky Mountain Research Station
Contributing office(s) Fort Collins Science Center
Description 5 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title National Proceedings: Forest and Conservation Nursery Associations – 2011
First page 82
Last page 86
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