Increased heat requirement for leaf flushing in temperate woody species over 1980-2012: effects of chilling, precipitation and insolation
Yongshuo Fu, Shilong Piao, Yann Vitasse, Hongfang Zhao, Hans De Boeck, Qiang Liu, Hui Yang, Ulrich Weber, Heikki Hänninen & Janssens Ivan A.
| Résumé |
Recent studies have revealed large unexplained variation in heat
requirement-based phenology models, resulting in large uncertainty
when predicting ecosystem carbon and water balance responses to
climate variability. Improving our understanding of the heat
requirement for spring phenology is thus urgently needed. In this
study, we estimated the species-specific heat requirement for leaf
flushing of 13 temperate woody species using long-term phenological
observations from Europe and North America. The species were defined
as early and late flushing species according to the mean date of
leaf flushing across all sites. Partial correlation analyses were
applied to determine the temporal correlations between heat
requirement and chilling accumulation, precipitation and insolation
sum during dormancy. We found that the heat requirement for leaf
flushing increased by almost 50% over the study period 1980–2012,
with an average of 30 heat units per decade. This temporal increase
in heat requirement was observed in all species, but was much larger
for late than for early flushing species. Consistent with previous
studies, we found that the heat requirement negatively correlates
with chilling accumulation. Interestingly, after removing the
variation induced by chilling accumulation, a predominantly
positive partial correlation exists between heat requirement and
precipitation sum, and a predominantly negative correlation between
heat requirement and insolation sum. This suggests that besides the
well-known effect of chilling, the heat requirement for leaf
flushing is also influenced by precipitation and insolation sum
during dormancy. However, we hypothesize that the observed
precipitation and insolation effects might be artefacts
attributable to the inappropriate use of air temperature in the
heat requirement quantification. Rather than air temperature,
meristem temperature is probably the prominent driver of the leaf
flushing process, but these data are not available. Further
experimental research is thus needed to verify whether insolation
and precipita- tion sums directly affect the heat requirement for
leaf flushing. |
| Mots-clés |
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| Citation | Fu, Y., Piao, S., Vitasse, Y., Zhao, H., De Boeck, H., Liu, Q., Yang, H., Weber, U., Hänninen, H., & Ivan A., J. (2015). Increased heat requirement for leaf flushing in temperate woody species over 1980-2012: effects of chilling, precipitation and insolation. Global change biology, 21(7), 2687-2697. |
| Type | Article de périodique (Anglais) |
| Date de publication | 1-7-2015 |
| Nom du périodique | Global change biology |
| Volume | 21 |
| Numéro | 7 |
| Pages | 2687-2697 |
| URL | http://onlinelibrary.wiley.com/doi/10.1111/gcb.12863/full |