Stem cycle analyses help decipher the nonlinear response of trees to concurrent warming and drought
High-resolution analysis of stem radius variation can quantify the impact of warming and drought on stem water balance and stem growth in black spruce [ Picea mariana (Mill.) B.S.P.)]. Drought affected plant water status and stem growth. However, warming affects the components of the circadian stem cycle differently if the impacts occur in the daytime or nighttime. The interactive effect of abiotic stresses had less impact on the circadian stem cycle than when the stresses occurred independently.
Warming and recent droughts in boreal regions reflect the multiple dimensions of climate change. How these climate-related stresses will affect the stem growth of trees remains to be described. Plant water relations can detect the dynamics of stem depletion and replenishment under conditions of climate-forced stress.
This study aimed to verify the impacts of a combination of asynchronous warming (nighttime versus daytime warming) and drought on stem water balance and stem growth in black spruce [Picea mariana (Mill.) B.S.P.)].
We investigated the water status and variations in stem radius of black spruce saplings growing in a controlled environment from May through August. We grew four-year-old saplings in warmer conditions either during the day (DW) or night (NW) at temperatures ca. 6 °C warmer than the ambient air temperature (CT). We then simulated a one-month drought in June. Automatic point dendrometers provided a high-resolution analysis of variations in stem radius, and we also monitored leaf water potentials and volumetric soil water content during the entire experimental period.
We detected significant reductions in stem radius variation under water deficit conditions. In the daytime warming scenario, we observed a significant increase in the duration of contraction and a decrease in expansion of the stems. The amplitude of this contraction and expansion was reduced under the nighttime warming conditions. The main effect of warming was to enhance drought stress by accelerating soil water depletion. Changes in predawn water potential drove the duration of stem circadian cycles under conditions of daytime warming, whereas irreversible growth dynamics drove these cycles under nighttime warming conditions due to the midday water potential. The interaction of night/daytime asynchronous warming and drought reduced the amplitude rather than the duration of stem contraction and expansion.
Water deficit decreased stem growth during the growing season. Asymmetric warming (as a single independent treatment) affected the timing and magnitude of stem circadian cycles. Under daytime warming scenarios, the duration of contraction and expansion were regulated mainly by predawn water potential, inducing longer (shorter) durations of contraction (expansion). Under nighttime warming, the smaller amplitudes of stem contraction and expansion were associated with midday water potential. Therefore, the interaction of abiotic stresses had less of an impact on the circadian stem cycle components than when these stresses were applied independently.
KeywordsAsynchronous warming Water deficit Point dendrometer Water status Saplings Black spruce
warmer conditions during the day at a temperature ca. 6 °C higher than CT
warmer conditions during the night at a temperature ca. 6 °C higher than CT
predawn leaf water potential (MPa)
midday leaf water potential (MPa)
volumetric water content (%)
We thank H. Morin, F. Gionest, G. Savard, and D. Gagnon for their support and technical advices. We give special thanks to M. Hay for checking the English text.
This study was funded by the Natural Sciences and Engineering Research Council of Canada and the Consortium Ouranos.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bauweraerts I, Ameye M, Wertin TM, McGuire MA, Teskey RO, Steppe K (2014) Water availability is the decisive factor for the growth of two tree species in the occurrence of consecutive heat waves. Agric For Meteorol 189-190:19–29. https://doi.org/10.1016/j.agrformet.2014.01.001 CrossRefGoogle Scholar
- Chan T, Hölttä T, Berninger F, Makinen H, Nojd P, Mencuccini M, Nikinmaa E (2016) Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal. Plant Cell Environ 39:233–244. https://doi.org/10.1111/pce.12541 CrossRefPubMedGoogle Scholar
- Deslauriers A, Morin H, Urbinati C, Carrer M (2003) Daily weather response of balsam fir (Abies balsamea (L.) Mill.) stem radius increment from dendrometer analysis in the boreal forests of Quebec (Canada). Trees-Struct Funct 17:477–484. https://doi.org/10.1007/s00468-003-0260-4 CrossRefGoogle Scholar
- Ellison D, Morris CE, Locatelli B, Sheil D, Cohen J, Murdiyarso D, Gutierrez V, Noordwijk M, Creed IF, Pokorny J, Gaveau D, Spracklen DV, Tobella AB, Ilstedt U, Teuling AJ, Gebrehiwot SG, Sands DC, Muys B, Verbist B, Springgay E, Sugandi Y, Sullivan CA (2017) Trees, forests and water: cool insights for a hot world. Glob Environ Chang 43:51–61. https://doi.org/10.1016/j.gloenvcha.2017.01.002 CrossRefGoogle Scholar
- Giovannelli A, Deslauriers A, Fragnelli G, Scaletti L, Castro G, Rossi S, Crivellaro A (2007) Evaluation of drought response of two poplar clones (Populus×canadensis Mönch ‘I-214’ and P. deltoides Marsh. ‘Dvina’) through high resolution analysis of stem growth. J Exp Bot 58:2673–2683. https://doi.org/10.1093/jxb/erm117 CrossRefPubMedGoogle Scholar
- Girardin MP, Bouriaud O, Hogg EH, Kurz W, Zimmermann NE, Metsaranta JM, de Jong R, Frank DC, Esper J, Büntgen U, Guo XJ, Bhatti J (2016a) No growth stimulation of Canada’s boreal forest under half-century of combined warming and CO2 fertilization. Proc Natl Acad Sci U S A 113:E8406–E8414. https://doi.org/10.1073/pnas.1610156113 CrossRefPubMedPubMedCentralGoogle Scholar
- Grossnickle SC (2000) Ecophysiology of northern spruce species: the performance of planted seedlings. NRC Press, Ottawa ISBN 0-660-17959-8, 407 pGoogle Scholar
- IPCC (2013) Climate change 2013: the physical science basis. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA 1535 pGoogle Scholar
- IPCC (2014) Climate Change 2014: Mitigation of Climate Change. In: Edenhofer O, Pichs-Madruga R, Sokona Y, Farahani E, Kadner S, Seyboth K, Adler A, Baum I, Brunner S, Eickemeier P, Kriemann B, Savolainen J, Schlömer S, von Stechow C, Zwickel T, Minx JC (eds) Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USAGoogle Scholar
- Mencuccini M, Salmon Y, Mitchell P, Hölttä T, Choat B, Meir P, O'Grady A, Tissue D, Zweifel R, Sevanto S, Pfautsch S (2017) An empirical method that separates irreversible stem radial growth from bark water content changes in trees: theory and case studies. Plant Cell Environ 40:290–303. https://doi.org/10.1111/pce.12863 CrossRefPubMedGoogle Scholar
- Zimmermann U et al (1994) Xylem water transport: is the available evidence consistent with the cohesion theory? Plant Cell Environ 17:1169–1118. https://doi.org/10.1111/j.1365-3040.1994.tb02015.x CrossRefGoogle Scholar