Responses of spring phenology in temperate zone trees to climate warming: A case study of apricot flowering in China uri icon

abstract

  • The timing of spring phenology in most temperate zone plants results from the combined effects of bothautumn/winter cold and spring heat. Temperature increases in spring can advance spring phases, butwarming in autumn and winter may slow the fulfilment of chilling requirements and lead to later onsetof spring events, as evidenced by recent phenology delays in response to warming at some locations.As warming continues, the phenology-delaying impacts of higher autumn/winter temperatures mayincrease in importance, and could eventually attenuate - or even reverse - the phenology-advancingeffect of warming springs that has dominated plant responses to climate change so far. To test thishypothesis, we evaluated the temperature responses of apricot bloom at five climatically contrasting sitesin China. Long-term records of first flowering dates were related to temperature data at daily resolution,and chilling and forcing periods were identified by Partial Least Squares (PLS) regression of bloom datesagainst daily chill and heat accumulation rates. We then analyzed the impacts of temperature variationduring the chilling and forcing periods on tree flowering dates for each site. Results indicated that incold climates, spring timing of apricots is almost entirely determined by forcing conditions, with warmersprings leading to earlier bloom. However, for apricots at warmer locations, chilling temperatures werethe main driver of bloom timing, implying that further warming in winter might cause delayed springphases. As global warming progresses, current trends of advancing phenology might slow or even turninto delays for increasing numbers of temperate species

publication date

  • 2015
  • 2015