Comparison of ecosystem and soil CO2 efflux in a beech (Fagus Sylvatica L.) forest

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Comparison of ecosystem and soil CO2 efflux in a beech

(Fagus Sylvatica L.) forest

Jérome Ngao, Bernard Longdoz, André Granier

To cite this version:

Jérome Ngao, Bernard Longdoz, André Granier. Comparison of ecosystem and soil CO2 efflux in

a beech (Fagus Sylvatica L.) forest. International symposium : Forests soils under global and local

changes : from research to practice, Sep 2004, Bordeaux, France. 1 p., 2004. �hal-02828196�

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COMPARISON OF ECOSYSTEM AND SOIL CO

₂

EFFLUX

IN A BEECH (

Fagus

Sylvatica

L

.

) FOREST

J

.

NGAO,

B. LONGDOZ,

A.

A. GRANIER

GRANIER

UMR Ecologie Ecophysiologie Forestière, INRA Nancy, 54280 Champe

UMR Ecologie Ecophysiologie Forestière, INRA Nancy, 54280 Champenouxnoux

2.

2. SITE

SITE

4.

4. MAP OF FLUX MEASUREMENTS

MAP OF FLUX MEASUREMENTS

Soil COSoil CO₂2efflux (efflux (SSRR) : a major component of forest carbon balance) : a major component of forest carbon balance

Partitioning the ecosystem COPartitioning the ecosystem CO₂2efflux (efflux (RRecoeco).).

Eddy covariance (Eddy covariance (ECEC) technique for S) technique for SRRmeasurements instead of widely measurements instead of widely

used closed dynamic chamber (

used closed dynamic chamber (CDCCDC) technique typically limited by low ) technique typically limited by low turbulences in below

turbulences in below--canopy situations.canopy situations.

Difference between sampling areas SDifference between sampling areas S_RRand Rand Recoeco measurements.measurements.

OverOver--or underestimations of Sor underestimations of SRRcontribution to Rcontribution to Recoeco..

Aim of the study : (i) To compare RAim of the study : (i) To compare Recoecoand Sand SRRfluxes measured at the Hesse fluxes measured at the Hesse

state forest (57, France). (ii) Determinism of R

state forest (57, France). (ii) Determinism of Recoecovariationsvariations

1. CONTEXT

98.0

867

867 F

F

SOIL

ECOSYSTEM

2003

G

E

D

C

B

A

Global

79.1

70.2

74.9

60.2

100.7

75.6

79.6

100.0

100.0 Comparison

Comparison

with R

ecoeco

(%)

700

621

662

532

890

668

704

884

884 CO

CO

22

Efflux

(g

CC

.m

--22

)

0 2 4 6 8 10 0 30 60 90 120 150 180 210 240 270 300 330 360 Day of year (2003) C O2 e ff lu x ( gC .m -2.d -1) Global Soil Respiration Ecosystem Respiration

Fig. 1

0 1 2 3 4 5 6 7 0 60 120 180 240 300 360 420 480 540 600

Day of year (since 2003)

S o il C O 2 e ff lu x ( g C .m -2.d -1) A B C D E F G

Fig. 2

RR_eco_ecomeasured continously with the EC method measured continously with the EC method (Photo 1). Averaged every 30 minutes.

(Photo 1). Averaged every 30 minutes.

SSRRmeasured with the CDC (Licor 6200 system, measured with the CDC (Licor 6200 system,

Photo 2) in 7 plots (from A to G, Map)

3.

3. MEASUREMENT SYSTEMS

MEASUREMENT SYSTEMS

Photo 2 Photo 2 Photo 1 Photo 1 A A B B C C D D EE F F G G A A B B C C D D EE F F G G N E W S LAI 5 LAI 5--77 LAI 3 LAI 3--55 LAI 7 LAI 7--9.59.5 BOR BOR BO BO Bre Bre

Soil Type Hydromorphism Soil Type Hydromorphism

Measurements every 2 weeks. Within each plot, n=12.Measurements every 2 weeks. Within each plot, n=12.

Dominant Wind Direction

LocationLocation: 48°40’, 7°05’E: 48°40’, 7°05’E

Mean annualMean annualrainfall :rainfall :820820mmmm

Mean annual temperatureMean annual temperature::9.2°9.2°CC

Soil TypeSoil Type: : Stagnic luvisolStagnic luvisol

SpeciesSpecies: 90% : 90% BeechBeech((F. sylvaticaF. sylvaticaL.)L.)

AgeAge: 35 : 35 yearsyears Mean LAIMean LAI: 7.3: 7.3

Hesse

State Forest (Northeast France)

Nancy

Nancy HesseHesse N E W S

6. RESULTS

Tab. 1

7. CONCLUSIONS

-

PERSPECTIVES

Significant discrepancies between global mean SSignificant discrepancies between global mean SRRand Rand Recoeco((Fig. 1Fig. 1).).

Significant differences between plots on seasonal SSignificant differences between plots on seasonal SRRflux evolution (flux evolution (Fig. 2Fig. 2) and annual CO) and annual CO22efflux efflux values (

values (Table 1Table 1): The contribution of S): The contribution of S_R_Rto Rto R_eco_ecomay change with wind direction.may change with wind direction.

Effect of LAI or soil type on SEffect of LAI or soil type on S_RRdifferences?differences?

Wind direction during the RWind direction during the Recoecomeasurements (measurements (Fig. 3Fig. 3) highlights the potential CO) highlights the potential CO22sources:sources:

In progress

: Footprint analysis for determination of relative flux contrib: Footprint analysis for determination of relative flux contribution.ution.

To compare RTo compare Recoecowith selected and weighted Swith selected and weighted SRRvalues from the footprint analysisvalues from the footprint analysis

Thanks to Bernard, Chef, Anne, Fanta.Thanks to Bernard, Chef, Anne, Fanta.

Work supported by the CarboEurope IP and the Work supported by the CarboEurope IP and the GIP

GIP--ECOFOR.ECOFOR.

0 0.06 0.12 0.18 0.24 0.3 0 30 60 90 120 150 180 210 240 270 300 330

Fig. 3

Frequency Frequency N N Wind Direction (°) Wind Direction (°)