Wood phenology: from organ-scale processes to terrestrial ecosystem models

Transcription

1 Wood phenology: from organ-scale processes to terrestrial ecosystem models Nicolas Delpierre Université Paris-Sud, Orsay, France

2

3 Phenology = study of the timing of detectable phase transitions between tissue states associated with major functional changes Organ phenology (leaf, fruits, wood, fine roots, CN reserves) Inter-organ phenological coordination Terrestrial Ecosystem Models need proper representations of phenological processes

4 Slide from Henri CUNY, ETH Zurich Seasonality of wood formation (Conifers) Phloem Cambium Late wood Early wood 2008 ring Phloem Cambium 2007 ring 2007 ring April Year 2008 October

5 Slide from Henri CUNY, ETH Zurich Seasonality of wood formation (Conifers) end of cell maturation Phloem Cambium Late wood Cambium 2007 ring start of cambium division Phloem Early wood 2007 ring 2008 ring April Year 2008 October

6 Terrestrial Ecosystem Models need representations of wood phenology Guillemot et al., under review

7 Wood phenology is largely ignored in TEMs Model Application scale Wood start Wood end CASA-CNP globe = leaves = leaves ED2.1 globe = leaves = leaves ISAM globe = leaves = leaves OCN globe =f(t), generic CLASS Forest stand =f(t), generic ANAFORE Forest stand = leaves = leaves CASTANEA Forest stand = leaves prescribed CASSIA Forest stand =f(t), specific Most Terrestrial Ecosystem Models consider key phenological events of wood to be simultaneous to leaf pheno. Summer growth end Evergreen species Delpierre et al., 2016, AFS

8 Coordinated phenology at the tree scale Typical patterns of leaf / wood phasing leaf = wood (leaf << wood) diffuse-porous deciduous wood < leaf ring-porous decid.+ conifers Michelot et al., 2012 Tree Phys Delaporte, 2010 (Master s thesis)

9 leaf phenology wood phenology LU Chêne LU Charme start halt FR-Fon Oak forest (France, temperate zone) Quercus petraea + Carpinus betulus Delpierre et al., 2016, New Phytol.

10 Estimating C allocation to wood db ( j, y) dv ( j, y) dt dt r B= biomasse (kg C m -2 ) V= volume (m 3 m -2 ) r=masse volumique (kg C m -3 ) Chêne, Barbeau Vallet et al., 2006 FEM

11 Normalized r(y) Estimating C allocation to wood db( j, dt y) dv ( j, dt y) r( y) B= biomasse (kg C m -2 ) V= volume (m 3 m -2 ) r=masse volumique (kg C m -3 ) Densité moyenne du cerne 3 r kg DM / m

12 Estimating C allocation to wood db( j, dt y) dv ( j, dt y) r( j, y) B= biomasse (kg C m -2 ) V= volume (m 3 m -2 ) r=masse volumique (kg C m -3 ) Tree ring % Tree ring % Cuny et al., 2014 NP

13 Still no such quantification in Angiosperms (PhD thesis A. Anandrianantenaina, B. superv. C Rathgeber) FR-Fon, Quercus petraea

14 Annual wood growth does not depend on C inputs Delpierre et al., 2016, New Phytol.

15

16 positive correlation p-value>0.10 negative correlation

17 Delpierre et al., 2016, New Phytol. AWG start (DOY) AWG halt (DOY) Annual wood growth depends on wood phenology start halt

18 Environmental determinants of wood phenology Delpierre et al., 2016 AFS summer spring spring summer end

19 Environmental determinants of wood phenology Ending phases of wood growth may respond to water stress Higher sensitivity than photosynthesis (Hsiao et al., 1976) Quercus petraea, FR-Fon Oak forest ( ) summer spring Delpierre et al., 2016 New Phytol.

20 Modelling the phenology of wood formation (deciduous trees) Quercus petraea, FR-Fon Oak forest ( ) wood start wood halt «spring warming» and «water stress integral» models simulate the interannual variability of wood phenophases Delpierre et al., 2016 New Phytol.

21 Modelling the phenology of wood formation (evergreen trees) wood start P. mariana, Canada (Qc) RMSE= 6 days P. mariana, Canada RMSE= 5 d observed predicted P. abies, Germany P. abies, Germany RMSE= 8 d «spring warming» model Delpierre, Lireux, Köstner, Rossi, unpublished

22 GLOBOXYLO consortium PhD thesis Ségolène LIREUX (superv. N Delpierre & C Rathgeber)

23 RMSD (gc/m²/yr) Wood phenology influences C allocation a constant allocation coefficients a i variable allocation coefficients a i b Delpierre et al. 2016, AFS Wood phenology modifies the seasonal C allocation pattern Crucial impact on simulated annual wood growth

24 Thank you for your attention CL2.03/AS4.19/BG1.21 «Phenology and seasonality in climate change and ecology» - EGU Vienna, 2016/04/18