International Journal of Biometeorology

, Volume 55, Issue 6, pp 775–787

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

  • Jonathan M. Friedman
  • James E. Roelle
  • Brian S. Cade
Original Paper

DOI: 10.1007/s00484-011-0494-6

Cite this article as:
Friedman, J.M., Roelle, J.E. & Cade, B.S. Int J Biometeorol (2011) 55: 775. doi:10.1007/s00484-011-0494-6


To explore the roles of plasticity and genetic variation in the response to spatial and temporal climate variation, we established a common garden consisting 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 at 29.2–47.6°N in the central United States. In the common garden both species showed latitudinal variation in fall, but not spring, leaf phenology, suggesting that the latitudinal gradient in fall phenology observed in the field results at least in part from inherited variation in the critical photoperiod, while the latitudinal gradient in spring phenology observed in the field is 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. For cottonwood, cold hardiness began earlier and ended later in northern than in southern populations. For saltcedar northern populations were hardier throughout the cold season than southern populations. 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.


Cold hardinessLatitudePhenologyRapid evolutionPopulus deltoidesTamarix

Supplementary material

484_2011_494_MOESM1_ESM.docx (14 kb)
Online Resource 1A table showing collection locations and number of individuals planted on 16 August 2005, for plains cottonwood and saltcedar grown in the common garden in Fort Collins, Colorado. (DOCX 13 kb)
484_2011_494_MOESM2_ESM.docx (48 kb)
Online Resource 2A figure showing variation in climate among collection locations. (DOCX 48 kb)
484_2011_494_MOESM3_ESM.docx (17 kb)
Online Resource 3A table showing mean values of phenological characters by latitude of origin. (DOCX 17 kb)
484_2011_494_MOESM4_ESM.docx (33 kb)
Online Resource 4A figure showing overwinter survival in the first year (2005–2006) for plains cottonwood and saltcedar in the common garden as a function of latitude of origin. (DOCX 32 kb)

Copyright information

© US Government 2011

Authors and Affiliations

  • Jonathan M. Friedman
    • 1
  • James E. Roelle
    • 1
  • Brian S. Cade
    • 1
  1. 1.US Geological Survey, Fort Collins Science CenterFort CollinsUSA