Climate and drought effects on forest carbon balance: lesson from three case studies

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Climate and drought effects on forest carbon balance:

lesson from three case studies

Denis Loustau, Damien Bonal

To cite this version:

Denis Loustau, Damien Bonal. Climate and drought effects on forest carbon balance: lesson from three case studies. Changement climatique, agriculture et forêt. Symposium bilatéral franco-allemand, May 2014, berlin, Germany. 22 p. �hal-02792932�

Climate and drought effects on forest carbon balance:

lesson from three case studies

Denis Loustau (1) Damien Bonal (2)

and colleagues

(1) Inra, ISPA, Villenave d’Ornon, France (2) Inra, EEF, Nancy , France

Ambassade de France, Berlin, June 7^th, 2014.

• With leap year adjustment: 2012 growth rate is 1.9% and 2013 is 2.4%

• Source

Global fossil fuel emissions

Full range of IPCC individual scenarios Averages

1990 1995 2000 2005 2010 2015

(GtC yr^-1)

5 6 7 8 9

10 A1B

A1FI RCP 8.5

A2

B1

B2 Carbon Dioxide Information Analysis Center

IAEA

Scenarios:

Data:

Number of hot days.yr

in France

2000 2070

Ruesch, et al. 2008. New IPCC Tier-1 Global Biomass Carbon Map For the Year 2000.

Scharlemann, J., Hiederer, R., Kapos, V. (2009). UNEP-WCMC & EU-JRC, Cambridge, UK.

Threatened areas include the largest terrestrial carbon stocks.

• Biomass in tropics

(Philips et al. 2009, 2010, Lewis et al, 2011)

• Soil carbon

(permafrost & boreal zone)

(Schuur et al. 2008, Muskett et Romanovsky, Natural Science, 2011)

1. Tropical forests

2. Broadleaved forests

3. Fast growing pine forest

Climate and drought effects on forest carbon balance:

case studies

 Soil carbon and water

 Growth and Biomass

Bioenergy forests (Estrées-Mons)

Broadleaved temperate forest (Nancy)

Coniferous forests (Bordeaux, Marseille)

INRA long term forest network

(1996- )

Nancy

Marseille - Bordeaux

Kourou

Lusignan

Clermont Mons

 Phenology

 Radiative balance

 Energy balance

 Hydrology

 Fluxes of CO2, O3, N,..

Broadleaved tropical forest (Kourou)

[ F-ORE-T ]

Observatoire de Recherche en Environnement Fonctionnement des écosystèmes forestiers

Integrated Carbon Observation System

The Guyaflux site in French Guiana (Europe) (French overseas department)

1. Amazonian forest: stand scale impacts.

2005

2005

2004

2004

Aug Sept Oct Nov Aug Sept Oct Nov

Aug Sept Oct Nov

Source

Sink

gC m^-2 for 92

days Dry 2004 Dry 2005

RE 975.6 888.6

GPP 1008.4 953.2

NEE 32.7 64.6

R

GPP

• Counter-intuitive increase in net CO₂ uptake during drought

- explained by a larger decrease in ecosystem respiration -.

Carbon Flux and Balance

NEE (=R

– GPP

)

1. Amazonian forest: immediate impacts at stand level.

2005 2004

Phillips et al. 2010 New Phytol.

• Large scale inventories have shown Amazonian rainforests were converted into a source of carbon by the 2005 drought (Philipps et al. 2009, Science)

• The increase in tree mortality correlates with drought intensity.

1. Amazonian case: delayed drought impacts at large-scale.

S L Lewis et al. Science 2011;331:554-554

1. Amazonian case: large-scale potential impacts.

• 2010 drought had a larger extend and severity;

• Repeated drought events have been leading the Amazonian rainforest

from a weak sink (Mahli, Grace, Lewis,…) to a source;

• Annual stem growth () is more resilient to concurrent soil water deficit than CO2 exchanges ( )

• But next year growth is severely depleted (Granier , unpublished)

Wet year Driest year Dry year

2. Drought effects observed in temperate forest:

instantaneous impacts.

Integrated Carbon Observation System

- 35 y-old beech forest in N-E France

carbon cycle monitored since 1996.

50 100 150 200 250

Ringwidth (10^-5 m)

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Oak Forests in Haguenau (Alsace) –

Bréda & Badeau, 2008, Geosciences

Dieback &

recovery Mortality

drought drought

Defoliation by Bombyx

• Droughts render individuals more vulnerable to subsequent stresses (defoliation by caterpillar)

2. Drought effects observed in temperate forest:

Long-term predisposition to mortality by previous drought.

Towers, 1998

Top view 2006 Ground view 1999

Chronosequence of Pine sites, SW France.

- Ecological and tree inventories from 1987 - Water balance 1988 -2008

- CO₂ flux from 1996 to 2008 - ¹⁴C Soil carbon dating in 2002

3. Drought effects observed in temperate forest:

Interaction with management in fast growing pine forests.

Integrated Carbon Observation System

-14 -7 0 7 14

0 91.5 183 274.5 366

Reco (gC m^-2)

GPP (gC m^-2)

-14 -7 0 7 14

0 91.5 183 274.5 366

Reco (gC m^-2)

GPP (gC m^-2)

-6 -3 0 3

6 NEE(gC m^-2)

-6 -3 0 3

6 NEE(gC m^-2)

01/01 01/04 01/07

Standard year Dry year

Bilos Bray

01/10

dd/mm

-14 -7 0 7 14

0 91.5 183 274.5 366

Reco (gC m^-2)

GPP (gC m^-2)

-14 -7 0 7 14

0 91.5 183 274.5 366

Reco (gC m^-2)

GPP (gC m^-2)

-6 -3 0 3

6 NEE(gC m^-2)

-6 -3 0 3

6 NEE(gC m^-2)

01/01 01/04 01/07

Standard year Dry year

Bilos Bray

01/10

dd/mm

Regenerating stand

Mature stand

• Drought turns NEE from sink into source

• Heterotrophic respiration is maintained

• Soil is still partly wet !

• Ecosystem NEE depleted but not reversed

• Respiration is strongly affected

• Soil is 100% dry

3. Drought effects observed in temperate forest:

Interaction with management in fast growing pine forests.

Cumulative CO₂ balance ^{(gC . m-2)}

-3000 -2000 -1000 0 1000 2000 3000

01/200001/200101/200201/200301/200401/200501/200601/200701/200801/200901/201001/2011

+ 807

- 2658

Dry year

Le Bray Bilos

clearcut

Deep plowing

SOWING

Deep plowing

Wind storm Mortality

20%

Thinning - 20%

- 3%

- 5%

Deep plowing + weeding + thinning

Wet Standard

clearcut

Plowing

• No significant post-drought effects

• Drought maintains young forest as a net source of carbon

• Temporal fluctuations in mature stand NEE are controlled by climate

3. Drought effects observed in temperate forest:

Interaction with management in fast growing pine forests.

GO+ model

• Biophysics

• Biogeoclemistry

• Carbon, water cycles

• Tree growth & production

• Management

• Harvest

Gridded data sets

• Soil class

• Forest area (species, age)

• Climate

Numerical investigations for the French Pine Forests case

X =

Soil Inventory Species & age distribution

Climate

1. Transitory mode:

predictions mapped over country area

• Management scenarios

• Soil class

• 1970-2100

Tillage NPK Stocking Thinnings Parts harvested

Age at clearcut

Pine Extensive ^(P60) 0 0 ^{1600 4 Stem 60}

Pine Standard ^{(P45) X} + ^{1600 6 Stem 45}

Pine Intensive ^{(P30) XXX} +++ ^{1600 1}

Stem Crown Stump

30

3. Drought effects modelling in temperate forest:

Mapping the interaction between climate and management in fast growing pine forests.

Predicted GPP according to management class 1970-2100 (as forced by A2 Scenario downscaled by model ARPEGE).

Gross Primary

Production ^{(gC.m-2.yr-1)}

Management class:

P30 P45

P60

Tillage /fertilisation/plantation:

Thinning / disking :

3000 2000 1000

0 1000 km

3. Drought effects modelled in temperate forest:

Mapping the interaction between climate and management in fast growing pine forests.

(Loustau et al., AGU 2013)

2

4 3

3000 1

2000 1000 0 3000 2000 1000 0

Centre

Mediterrannean Pyrenean Foremounts

Atlantic

1000 km

Gross Primary Production

(gC.m^-2.yr^-1)

Manag^t class:

P30 P45 P60

1. Transitory mode

predictions:

mapping over country area (9600 grid points)

• Management scenarios

• Soil class 80

• 1970-2100

Plots of Soil

Carbon (gC.m

) P30

P45

P60

• NEE map

• Soil C plots

1000

0 -1000

Plots of Biomass Stock (kg dm .m

) P30

P45

P60

Centre

Mediterrannean Pyrenean Foremounts

Atlantic

• NEE map

• Standing

Biomass plots

DGWP₃₀ (W.m^-2)

3. Overall impacts of forest conversion on GWP

Global warming potential of management intensification from P60  P30

-2.00E-03 -1.00E-03

0.00E+00

1985

2015

2045

2085

CO

Albedo

3. Drought effects modelled in temperate forest:

Management impacts on climate are weakened under future drier climates

(Loustau et al., EGU 2014)

Main points to take home.

• All forest types are exposed to droughts

• Trees respond at a range of time scale from hour to century

• How far does drought weaken the biosphere carbon sink is unknown.

• Release of carbon from declining forests will feed-forward the climate

disturbance

INRA ISPA SUPPORT

• Denis Loustau

• Virginie Moreaux*

• Alexandre Bosc

• Delphine Picart

• Christophe Moisy

INRA EEF

• Damien Bonal

• Nathalie Bréda

• Bernard Longdoz

• André Granier

* (present address San Diego University)