Appropriate citations include:

Thornley J (1998). “Modelling shoot : root relations: the only way forward?” Annals of Botany, 81(2), 165-171. doi:10.1006/anbo.1997.0529.

Higgins S, O’Hara R, Bykova O, Cramer M, Chuine I, Gerstner E, Hickler T, Morin X, Kearney M, Midgley G, Scheiter S (2012). “A physiological analogy of the niche for projecting the potential distribution of plants.” Journal of Biogeography, 39(12), 2132-2145. ISSN 1365-2699.

Higgins S, Conradi T, Muhoko E (2023). “Shifts in vegetation activity of terrestrial ecosystems attributable to climate trends.” Nature Geoscience, 16(2), 147+. doi:10.1038/s41561-022-01114-x.

Higgins S, Burkhardt A, Conradi T, Muhoko E (2025). “TTR.PGM: An R package for modeling the distributions and dynamics of plants using the Thornley transport resistance plant growth model.” Methods in Ecology and Evolution, 100(1), 000-000.

The TTR model was proposed and described by Thornley 1988. Higgins et al. 2012 added environmental forcing to the TTR model and interpreted it as a species distribution model. Higgins et al. 2023 interpret the TTR model as a time series model. Higgins et al. 2025 describe the R package.

Corresponding BibTeX entries:

  @Article{,
    title = {Modelling shoot : root relations: the only way forward?},
    author = {J H M Thornley},
    journal = {Annals of Botany},
    year = {1998},
    volume = {81},
    number = {2},
    pages = {165-171},
    month = {FEB},
    doi = {10.1006/anbo.1997.0529},
  }

  @Article{,
    title = {A physiological analogy of the niche for projecting the
      potential distribution of plants},
    author = {Steven I. Higgins and Robert B. O’Hara and Olga Bykova
      and Michael D. Cramer and Isabelle Chuine and Eva-Maria Gerstner
      and Thomas Hickler and Xavier Morin and Michael R. Kearney and
      Guy F. Midgley and Simon Scheiter},
    journal = {Journal of Biogeography},
    year = {2012},
    volume = {39},
    number = {12},
    pages = {2132-2145},
    issn = {1365-2699},
  }

  @Article{,
    title = {Shifts in vegetation activity of terrestrial ecosystems
      attributable to climate trends},
    author = {Steven I. I. Higgins and Timo Conradi and Edward Muhoko},
    journal = {Nature Geoscience},
    year = {2023},
    volume = {16},
    number = {2},
    pages = {147+},
    month = {FEB},
    doi = {10.1038/s41561-022-01114-x},
  }

  @Article{,
    title = {TTR.PGM: An R package for modeling the distributions and
      dynamics of plants using the Thornley transport resistance plant
      growth model},
    author = {Steven I. Higgins and Arne Burkhardt and Timo Conradi and
      Edward Muhoko},
    journal = {Methods in Ecology and Evolution},
    year = {2025},
    volume = {100},
    number = {1},
    pages = {000-000},
  }