Daniel MetcalfeOxford University Centre for the Environment

daniel.metcalfe@ouce.ox.ac.uk

Comprehensive monitoring of carbon allocation and cycling

across the Amazon basin

Objectives

1) Establish baseline of current forest carbon storage and allocation

2) Monitor ongoing changes in forest carbon cycling

Increasing COIncreasing CO22 “fertilizer” in the “fertilizer” in the

atmosphereatmosphere

0 0.1 0.2 0.3 0.4 0.5 0.6

NW Amazonia

NE Amazonia

N Congo

E Indonesia

SW India

W Africa

C Amazonia

SW Amazonia

Cameroon

W Indones

S Congo

C America

SE Amazonia

Rate of Temperature Change (oC/decade)

SENSITIVITY: TEMPERATURESENSITIVITY: TEMPERATURE

Malhi and Wright (2004), Philosophical Transactions of the Royal Society

↓ precipitation ↑ atmospheric CO2 levels

↓ photosynthesis & ↑ soil respiration

↑ temperature

↑ terrestrial CO2 emissions↑ replacement of forest with savannah

IPPC 2007 working group 1 report

Dry seasonlength

+-

Current trends: spatial variation

Field Sites

Caxiuana

Tanguro

Noel Kempff

Kosnipata

Iquitos

Tambopata

Comparisons • Drought• Soil type• Fire• Altitude

Ecosystem respiration Net primary production

Rstem

Rleaf

Rsoil

Pcanopy

Pstem

ProotRcwd

Mleaf

Mroot

Mstem

Constructing bottom-up carbon budgets

Rsoil

Rroots

Rmycorrhizae

Rsom

Rlitter

Soil CO2 efflux partitioning

Constructing bottom-up carbon budgetsGPPflux tower = 30.4; Predicted GPP = 29.9 � 4.8Manaus, Brazil

R leaf = 10.0 � 4.0

R stem = 4.2 � 1.0

R CWD = 2.5� 0.3

R total = 29.3 � 4.7

R aut = 19.8 � 4.6

R het = 9.6 � 1.2

NPPtotal = 10.1 � 1.4

NPPAG = 7.3 � 1.3

NPPBG = 2.8 � 0.7

Fdoc = 0.19 � 0.07

DFine litterfall = 3.6 � 0.7

DCWD= 3.4� 1.0

R roots = 5.6 � 2.0

Predicted R soil = 12.6±2.3

Measured R soil = 12.1 � 1.7

DRoot = 2.8 � 0.7

R soil het.=7.1 � 1.1

NPP coarse roots = 0.8 � 0.2

NPP fine roots = 2.1 � 0.7

NPP stem = 2.58 � 0.06

NPP VOC = 0.13 � 0.06NPP leaves,flowers,fruit = 3.6 � 0.7

NPP branch turnover = 1.0 � 1.0

Equipment contruction & installation

Ecosystem respiration Net primary production

Rstem

Rleaf

Rsoil

Pcanopy

Pstem

ProotRcwd

Mleaf

Mroot

Mstem

Pcanopy

Pstem

Mleaf

Mstem

Foliage densityFoliage density

ClassificationClassification

OutputsOutputs

Specific leaf areaSpecific leaf area

Threshold image to calculate area

Fill in eaten leaf area to quantify herbivory

Leaf morphology

Variation with canopy height

Leaf dark respiration

Leaf light respiration

Ecosystem respiration Net primary production

Rstem

Rleaf

Rsoil

Pcanopy

Pstem

ProotRcwd

Mleaf

Mroot

Mstem

Stem Dynamics

Measurements1)Below and above 10cm DBH2) Basic data (species, DBH, height wood density)3) Mode of death4) Respiration......basal vs contruction respiration

Res

pira

tion

Growth

Biomass change / Mg ha-1 yr-1

0

2

4

6

8

10

12

14

16

18

-4 -3 -2 -1 0 1 2 3 4 5 6

No

. plo

ts

1.22 ± 0.42 Mg ha-1 yr-1

Histogram of rate of biomass change over the 1980s and 1990s as observed in 59 RAINFOR plots. The mean change is 1.22±0.42 Mg biomass ha-1 year-1. From Baker et al (2004), Philosophical Transactions of the Royal Society of London.

Current trends: Increasing biomass

Changes in tree recruitment (green) and mortality as observed in RAINFORold-growth forest plots in recent decades. Forests appear to be becoming Increasingly dynamic. From Phillips et al (2004)

An

nu

al r

ate

of

stem

m

ort

alit

y/re

cru

itm

ent

(%)

Year

Current trends: Increasing dynamism

Ecosystem respiration Net primary production

Rstem

Rleaf

Rsoil

Pcanopy

Pstem

ProotRcwd

Mleaf

Mroot

Mstem

Ecosystem respiration Net primary production

Rstem

Rleaf

Rsoil

Pcanopy

Pstem

ProotRcwd

Mleaf

Mroot

Mstem

TECHNIQUES: RHIZOTRONSTECHNIQUES: RHIZOTRONS

1.1. In situIn situ measurement measurement2.2. High temporal frequencyHigh temporal frequency3.3. Record root growth, Record root growth,

mortality, longevitymortality, longevity

RHIZOTRONS: CONVERTING LENGTH TO MASS RHIZOTRONS: CONVERTING LENGTH TO MASS

Calculate cross-sectional root area

Multiply area by length/width of plot to derive volume

Multiply volume by root density

Frequent root mass production (t ha-1)rhizotron screenrhizotron screen

rootsroots

Source: Bernier & Robitaille. (2004), Plant and Soil.

TECHNIQUES: INFRA-RED GAS ANALYZERTECHNIQUES: INFRA-RED GAS ANALYZER

CO2

IRGAIRGA

1.1. Record soil respirationRecord soil respiration

2.2. Remove litter, measure respiration againRemove litter, measure respiration again

3.3. Remove soil core, roots from core. Measure Remove soil core, roots from core. Measure root respiration.root respiration.

4.4. Subtract root and litter respiration from total Subtract root and litter respiration from total soil respirationsoil respiration

isolate litter isolate litter contributioncontribution

estimate root estimate root contributioncontribution

estimate residual estimate residual respiration (i.e.: from respiration (i.e.: from soil organic matter)soil organic matter)

Soil CO2 efflux partitioning

No litterControl 2 × litter

Control

No roots or mycorrhizae

No roots

Key websites- The Amazon Forest Inventory Network:

http://www.geog.leeds.ac.uk/projects/rainfor/- Project for the Advancement of Networked Science in Amazonia:

http://www.eci.ox.ac.uk/projects/panamazonia/- Large Scale Atmosphere-Biosphere Experiment in Amazonia:

http://www.lbaeco.org/lbaeco/

Daniel MetcalfeDaniel Metcalfedaniel.metalfe@ouce.ox.ac.ukdaniel.metalfe@ouce.ox.ac.uk

Caxiuana

Tanguro

Noel KempffAndesTransect

Iquitos

Lloyd (1999), Functional Ecology.

The The current effect of CO effect of CO22 fertilizer on fertilizer on

terrestrial ecosystemsterrestrial ecosystems

Synthesis of results

1.1. Good evidence for drought-induced decline in Good evidence for drought-induced decline in photosynthesis, photosynthesis, but this is balanced out by a decline in soil this is balanced out by a decline in soil COCO22 efflux. efflux. What accounts for inter-annual patterns?

2.2. Some evidence for drought-induced changes in mortality Some evidence for drought-induced changes in mortality and reproduction, and reproduction, but massive variability. massive variability.

3.3. Overall, the forest appeared suprisingly resilient to droughtOverall, the forest appeared suprisingly resilient to drought

BUT

Other poorly quantified components of the carbon cycleOther poorly quantified components of the carbon cycle

Robustness of the modelled “Amazon Robustness of the modelled “Amazon drought”drought”

Short-term model predictions:Short-term model predictions: Climate & Carbon Climate & Carbon

Differences amongst regionsDifferences amongst regions

Long-term model predictions:Long-term model predictions: Vegetation Vegetation

Long-term model predictions:Long-term model predictions: vegetation vegetation

↑ atmospheric CO2 levels↓ precipitation

↓ photosynthesis & ↑ soil respiration

↑ temperature

↑ terrestrial CO2 emissions

e.g.: see Cox et al. (2000), Nature.

↑ replacement of forest with savannah

Results from the first two years: soil moisture

Results from the first two years: canopy properties

Results from the fifth year: canopy properties

Results: tree dynamics

Mortality over 3 yearsMortality over 3 years

Control: 2.4% of pop.Control: 2.4% of pop.

TFE: 1.5% of pop.TFE: 1.5% of pop.

BUT

Control: 1.3 t C haControl: 1.3 t C ha-1-1

TFE: 2.1 t C haTFE: 2.1 t C ha-1-1

↑ atmospheric CO2 levels↓ precipitation

↓ photosynthesis & ↑ soil respiration

↑ temperature

↑ terrestrial CO2 emissions

e.g.: see Cox et al. (2000), Nature.

↑ replacement of forest with savannah

Overlooked components of the C cycle

Leaf dark respiration

TEMPORAL TRENDS: RESPIRATIONTEMPORAL TRENDS: RESPIRATION

Model uncertainty caused mainly by lack Model uncertainty caused mainly by lack of information about below-ground of information about below-ground processesprocesses

Source: Lloyd & Prentice (1998), Nature.

RHIZOTRONS: RESULTS RHIZOTRONS: RESULTS

surge in both growth surge in both growth and mortality during and mortality during

the wet seasonthe wet season

Additional surge on Additional surge on the Drought plot the Drought plot

coinciding with the coinciding with the first big rain eventsfirst big rain events

? ? ?

SYNTHESIS: ABOVE- & SYNTHESIS: ABOVE- & BELOW-GROUND DATABELOW-GROUND DATA

0

1

2

3

4

5

6

7

control drought

tC h

a-1

yr-1

litter- rep.

litter- leaveslitter- wood

stemroot

Treatment differences in stem wood Treatment differences in stem wood production are relatively small compared production are relatively small compared

to root and litter fall productionto root and litter fall production

The drought treatment alters ecosystem The drought treatment alters ecosystem carbon cycling, e.g.: the balance between carbon cycling, e.g.: the balance between carbon entering the soil via litter fall, and carbon entering the soil via litter fall, and

leaving via microbial respirationleaving via microbial respiration

Accounts for 45% of the worlds tropical forestAccounts for 45% of the worlds tropical forest

Stores 40% of carbon residing in terrestrial vegetationStores 40% of carbon residing in terrestrial vegetation

Hosts a large proportion of global biodiversityHosts a large proportion of global biodiversity

Malhi & Grace (2000), TREE.