The timing of bud break in warming conditions: variation among seven sympatric conifer species from Eastern Canada
Phenological changes are expected with the ongoing global warming, which could create mismatches in the growth patterns among sympatric species or create synchrony with insect herbivores. In this study, we performed a comparative assessment of the timings of bud break among seven conifer species of Eastern Canada by evaluating seedling development in growth chambers under different temperatures (16, 20 and 24 °C). Bud break occurred earliest in Larix laricina, while Pinus strobus and Pinus resinosa had the latest. Warmer conditions advanced bud break, with the greatest effects being observed at the lower temperatures. Mixed models estimated that one additional degree of temperature produced advancements of 5.3 and 2.1 days at 16 and 20 °C, respectively. The hypothesis of an asynchronous change between species under warming was demonstrated only for the last phenological phases (split buds and exposed shoots), and principally in pines. Abies balsamea showed changes in bud break comparable with the other species analysed, rejecting the hypothesis of mismatches under warmer conditions. The observed non-linear responses of the timings of bud break to warming suggest that the major changes in bud phenology should be expected at the lowest temperatures.
KeywordsBud burst Temperature Boreal forest Non-linear relationship
This work was funded by grants from Natural Resources Canada, Consortium de Recherche sur la Forêt Boréale Commerciale, and Canada Foundation for Innovation. The authors thank S. Carles, J. Gravel-Grenier and V. Néron for technical support and A. Garside for editing the English text.
- Dhont C, Sylvestre P, Gros-Louis M-C, Isabel N (2010) Field guide for identifying apical bud break and bud formation stages in white spruce. Natural Resources Canada, QuebecGoogle Scholar
- IPCC (2013) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UKGoogle Scholar
- Nord EA, Lynch JP (2009) Plant phenology: a critical controller of soil resource acquisition. J Exp Biol 60:1927–1937Google Scholar
- Park YS, Fowler DP (1982) Effects of inbreeding and genetic variances in natural population of tamarack (Larix laricina) (Du Roi) K. Koch in eastern Canada. Silvae Genet 31:21–26Google Scholar
- Rossi S, Isabel N (2017) Bud break responds more strongly to daytime than night-time temperature under asymmetric experimental warming. Glob Chang Biol. 23:446-454Google Scholar
- Rossi S, Deslauriers A, Anfodillo T, Carrer M (2008) Age-dependent xylogenesis in timberline conifers. New Phytol 177:199–208Google Scholar
- Wolkovich EM et al (2012) Warming experiments underpredict plant phenological responses to climate change. Nature 485:494–497Google Scholar