relationships between gpp, npp, nep, ra, rh and re in forest ecosystems sebastiaan luyssaert with...

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Sebastiaan Luyssaert

with contributions of 40+ research groups

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• Forest play an important role in the global C-cycle

• Since 1970 ongoing effort to estimate production and respiration

• Considerable uncertainties remain

• Assembled a comprehensive global database

Introduction

Objectives

• Explain some important feature of the database

• Identify data gaps

• Present relationships GPP, NPP, NEP, Ra, Rh and Re

• Present CO2-budgets per biome

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Sebastiaan Luyssaert and contributions of 40+ research groups

The database

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• Consistent NPP data

• Consistent uncertainty

• Ancillary information

Sebastiaan Luyssaert and contributions of 40+ research groups

The database

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Expert judgement accounting for :

- Applied methodology

- Number of observations

• Consistent NPP data

• Consistent uncertainty

• Ancillary information

Sebastiaan Luyssaert and contributions of 40+ research groups

The database

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• Consistent NPP data

• Consistent uncertainty

• Ancillary information

- Coordinates, elevation, climatic region,

growth form, management, tree species- Observed MAT, APS, LAI, age, height,

BA, diameter, density, biomass- Monthly temperature, precipitation,

rainy days, cloud cover data CRU- Modelled radiation components, air

humidity, N-deposition, soil composition- NDVI

Sebastiaan Luyssaert and contributions of 40+ research groups

Data

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• 2000+ flux observations

• 380 sites

• 130 GPP, Re & NEP

• 250 NPP

• 130 Rh & Rs

• 35 Ra

Sebastiaan Luyssaert and contributions of 40+ research groups

Data gaps

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• For GPP, NPP, NEP & Re

need:

- Boreal ecosystems

- Tropical ecosystems

Sebastiaan Luyssaert and contributions of 40+ research groups

Data gaps

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

• For Ra & Rh need:

- All biomes except temperate

humid

Sebastiaan Luyssaert and contributions of 40+ research groups

Dependence of GPP

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Sebastiaan Luyssaert and contributions of 40+ research groups

• High GPP: warm wet

• Low GPP: cold dry

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

?

Dependence of GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

?

Dependence of GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

?

Dependence of GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of GPP, NPP, Re and Rh

• GPP ~ MAT, LAI, P

• NPP ~ MAT, LAI, Rg

• Re ~ MAT, LAI, P

• Rh ~ MAT, ?

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NEP

• NEP ~ GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NEP

• NEP ~ GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NEP

NEP ?

• Age

• Management

Sebastiaan Luyssaert and contributions of 40+ research groups

source

sink

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NPP/GPP

Ra, insuf. data

• NPP/GPP

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NPP/GPP

• NPP/GPP data

• NPP/GPP max

production

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NPP/GPP

NPP/GPP unmanaged

sites

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Dependence of NPP/GPP

Management > Temp

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Components of the CO2-balance

• Benchmark for model validation

• Closure problem

Sebastiaan Luyssaert and contributions of 40+ research groups

Closure of the CO2-balance

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Global CO2-balance

• Uncertainty when models

follow the observations

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Conclusions

• Database of field-observations available for model validation

• Missing 2 out of 8 climate regions

• Climate dependence of GPP, NPP, Re but not of NEP

• NPP/GPP ratio is not 0.475

• Substantial closure terms indicate shortcomings of field-observations

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

We want more...

• Presentation Denis Lousteau: Management effects on the annual

carbon balance of forests

• Poster Ilaria Inglima: NPP drives Rh in forest ecosystems

• Task force presentations Martin Jung: Comparison of models and

observations

Sebastiaan Luyssaert and contributions of 40+ research groups

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

ContributorsI. Inglima, M. Jung, M. Reichstein, D. Papale, S. Piao, E.-D. Schulze, L. Wingate, G. Matteucci, M. Aubinet, C. Beer, C. Bernhofer, K.G. Black, D. Bonal, J.Chambers, P. Ciais, K.J. Davis, E.H. Delucia, A.J. Dolman, A. Don, B. Gielen, J. Grace, A. Granier, A. Grelle, T. Griffis, T. Grünwald, G. Guidolotti, P.J. Hanson, R. Harding, D. Hollinger, P. Kolari, B. Kruijt, W. Kutsch, F. Lagergren, T. Laurila, B. Law, G. Le Maire, A. Lindroth, F. Magnani, M. Marek, J. Mateus, M. Migliavacca, L. Misson, L. Montagnani, J. Moncrieff, E. Moors, J.W. Munger, E. Nikinmaa, D. Loustau, G. Pita, C. Rebmann, A.D. Richardson, O. Roupsard, N. Saigusa, M.J. Sanz, G. Seufert, L. Soerensen, J. Tang, R. Valentini, T. Vesala and I. Janssens

Funding

Belgian Research Foundation (FWO), CarboEurope-IP and Antwerp University

Sebastiaan Luyssaert and contributions of 40+ research groups