Extended Data Figure 9: Changes in chilling accumulation and modelled correlation between chilling and apparent temperature sensitivity of leaf unfolding.
From: Declining global warming effects on the phenology of spring leaf unfolding
a, Chilling accumulation for individual species and for combined totals for all species with 15-year moving windows from 1980 to 2013. The chilling accumulation was calculated as chilling days when daily temperature was between 0 °C and 5 °C from 1 November to the average date of leaf unfolding. The black line indicates the average across all species, and the grey area indicates one s.d. either side of the mean. The dotted line indicates the linear regression. b, Same as Fig. 2b, but chilling accumulation was calculated as chilling days when daily temperature was below 5 °C from 1 November to the average date of leaf unfolding. The asterisks indicate significant differences at P < 0.05. c, The modelled (unified model) ST under different artificial winter warming conditions. The temperature in winter, defined as the period from the 1 November to 31 January, was warmed by +1 °C to +5 °C over the period 1980–2013. The points with most chilling days indicate the real winter temperatures, and each of the other points indicate one winter warming treatment. The lines indicate simple linear regressions.
