Florian Hartig Theoretical Ecology & Ecological Data Science

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Chilling and forcing temperatures interact to predict the onset of wood formation in Northern Hemisphere conifers

Nicolas Delpierre, Ségolène Lireux, Florian Hartig, J. Julio Camarero, Alissar Cheaib, Katarina Čufar, Henri Cuny, Annie Deslauriers, Patrick Fonti, Jo\v zica Gričar, Jian-Guo Huang, Cornelia Krause, Guohua Liu, Martin de Luis, Harri Mäkinen, Edurne Martinez del Castillo, Hubert Morin, Pekka Nöjd, Walter Oberhuber, Peter Prislan, Sergio Rossi, Seyedeh Masoumeh Saderi, Vaclav Treml, Hanus Vavrick, Cyrille B. K. Rathgeber

Global Change Biology, 25(3), 1089–1105 (2019)
Cite this
@article{delpierre2019chilling,
  author = {Nicolas Delpierre and Ségolène Lireux and Florian Hartig and J. Julio Camarero and Alissar Cheaib and Katarina Čufar and Henri Cuny and Annie Deslauriers and Patrick Fonti and Jo\v zica Gričar and Jian-Guo Huang and Cornelia Krause and Guohua Liu and Martin de Luis and Harri Mäkinen and Edurne Martinez del Castillo and Hubert Morin and Pekka Nöjd and Walter Oberhuber and Peter Prislan and Sergio Rossi and Seyedeh Masoumeh Saderi and Vaclav Treml and Hanus Vavrick and Cyrille B. K. Rathgeber},
  title = {Chilling and forcing temperatures interact to predict the onset of wood formation in Northern Hemisphere conifers},
  journal = {Global Change Biology},
  volume = {25},
  number = {3},
  pages = {1089–1105},
  year = {2019},
  doi = {10.1111/gcb.14539},
}

DOI: 10.1111/gcb.14539
Cited by 143 (Google Scholar) · 124 (OpenAlex), as of 07 September 2026

View article (DOI)

Abstract

The phenology of wood formation is a critical process to consider for predicting how trees from the temperate and boreal zones may react to climate change, but compared to leaf phenology, the determinism of wood phenology is still poorly known. Here we compared for the first time three alternative ecophysiological model classes (threshold models, heat-sum models and chilling-influenced heat-sum models) and an empirical model in their ability to predict the starting date of xylem cell enlargement in spring, for four major Northern Hemisphere conifers (Larix decidua, Pinus sylvestris, Picea abies and Picea mariana). We fitted models with Bayesian inference to wood phenological data collected for 220 site-years over Europe and Canada. The chilling-influenced heat-sum model received most support for all four studied species, predicting validation data with a 7.7-day error, within one day of the observed data resolution, and showed virtually no spatial bias whichever the species, despite the large environmental gradients considered. We conclude that both chilling and forcing temperatures determine the onset of wood formation in Northern Hemisphere conifers, and that the spring onset of wood formation is far less affected by local adaptation than by environmentally driven plasticity. In a context of climate change, we therefore expect rising winter-spring temperature to exert ambivalent effects on the spring onset of wood formation, tending to hasten it through the accumulation of forcing temperature, but imposing a higher forcing temperature requirement through the lower accumulation of chilling.

What the paper shows and why it matters (AI-generated)

Wood-formation phenology has received far less modelling attention than leaf phenology, despite mattering just as much for how conifers will respond to warming. Comparing four model classes against 220 site-years of European and Canadian data, the authors find that spring wood formation depends on both cold winter (chilling) and warm spring (forcing) signals jointly — meaning warming's effect on timing is genuinely ambivalent, hastening growth via forcing while simultaneously raising the forcing threshold needed to compensate for reduced chilling, not the simple “warmer means earlier” story a leaf-phenology model would predict.