Chronosequence of soil respiration in ChEAS sites (sub-topic of spatial upscaling of carbon...
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Transcript of Chronosequence of soil respiration in ChEAS sites (sub-topic of spatial upscaling of carbon...
Chronosequence of soil respiration in ChEAS sites
(sub-topic of spatial upscaling of carbon measurement)
Jim Tang
Department of Forest Resources
University of Minnesota
Factors for simulating long-term forest carbon dynamics
• Natural variability and disturbance
• Human disturbance and management
• Climate change: T, precipitation…
• Increasing atmospheric CO2 concentration and nitrogen deposition -- fertilization
• Forest succession
Why chronosequence
• Our knowledge in understanding the influence of forest succession on carbon dynamics is limited.
• Most long-term carbon simulation models do not consider forest succession as a variable.
Forest stands with different ages
Old-growthMature
YoungClear-cut
Soil respiration measurement
Soil temperature in clear sites
DOY
120 140 160 180 200 220 240 260 280 300 320
Soi
l tem
pera
ture
(o C
)
4
6
8
10
12
14
16
18
20
22
24
26
28
Burned Blowdown Residual Regeneration
Soil temperature from young to old
DOY
120 140 160 180 200 220 240 260 280 300 320
Soi
l tem
pera
ture
(o C
)
4
6
8
10
12
14
16
18
20
22
24
26
28
YA IA MH OG
Soil temperature
Chronosequence of soil respiration in response to temperature
Young - old
Temperature (oC)
4 6 8 10 12 14 16 18 20 22
Soi
l res
pira
tion
(m
ol m
-2 s
-1)
0
1
2
3
4
5
6
7
8
9
10
YAIAMHOG
Q10 = 3.12
Q10 = 3.09
Q10 = 2.87
Q10 = 2.31
YA: Young aspen IA: intermediate aspen MH: mature hardwood OG: old-growth
Clear sites
Temperate (oC)
4 6 8 10 12 14 16 18 20 22
Soi
l res
pira
tion
(m
ol m
-2 s
-1)
0
1
2
3
4
5
6
7
8
9
10
Burned BlowdownResidualSeedling
Q10 = 1.92
Q10 = 3.40
Q10 = 5.49
Q10 = 2.34
Flu
x (
mol
m-2
s-1
)
1.0
1.5
2.0
2.5
3.0
Soil temperature
Tem
pera
ture
(o C
)
14
15
16
17
18
19Burned
Residual
Blowdown/seedling
YAIA MH
OG
Burned
BlowdownYA
IAMH
OGSeedling
Soil respiration at 10oCResidual
Mean soil respiration
Year
0 50 100 150 200 250 300 350
flux
(m
ol m
-2 s
-1)
3.0
3.5
4.0
4.5
5.0
Burned
Blowdown
YA IA
MH
OG
Seedling/residual
Chronosequence of soil respiration
Soil carbon storage
Car
bon
sto
rag
e (g
C m
-2)
0
2000
4000
6000
8000
10000
Soil nitrogen storage
Year
0 50 100 150 200 250 300 350
Nitr
oge
n st
ora
ge (
gN m
-2)
0
100
200
300
400
500
600
a.
c.
y = k0 xk1 ek2x, r2 = 0.994
Blowdown
Residual
Regeneration
Burned
YA
IA MH
OG
Blowdown
Residual
Regeneration
Burned
YA IAOG
MH
Annual change of soil carbon
dC/d
t (g
C m
-2 y
r-1)
0
100
200
300
b.
Regeneration
YAIA MH OGy = 0
y = k0 xk1 ek2x(k1x
-1+ k2)
Chronosequence of soil carbon content, annual change of soil carbon, and nitrogen content
Soil Woody debris Stem Leaf Ecosystem
Res
pira
tion
(gC
m-2
y-1
)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
YAIA MH OHD OHL
1089
1295
1027
935
54105 109
69
225
148132209
809
1043
742
628
4530
837
1894
949
YA: young aspen, IA: intermediate aspen. MH: mature hardwood, OHD: old-growth hardwood, OHL: old-growth hemlock
Tang et al., 2006. Agri. For. Met., in press
Cumulative respiration and components
Odum, 1969, Science Ryan et al. 1997, Ad. Eco. Res.
Young Mautre Old
An
nu
al ca
rbo
n f
lux
NEP
GPP
Ecosystem Respiration
NEP
Young Mautre Old
GPP
Ecosystem Respiration
Successional pattern of carbon flux: two conceptual models
Simulate long-term large-scale soil carbon
Year
1900 1950 2000 2050 2100
Car
bon
stor
age
(gC
m-2
)
0
2000
4000
6000
8000
10000
12000
Clearcut
100
Total soil Carbon
Slow soil C
Passive soil C
Active soil C
Measured C
Century model
Published work
Chamber (mol m-2 s-1)
0 1 2 3 4 5 6 7 8 9 10
Ed
dy
cova
rian
ce ( m
ol m
-2 s-1
)
0
1
2
3
4
5
6
7
8
9
10
y = 1.292x - 0.862,r2 = 0.96
y = x
Eddy Covariance vs. chamber measurements
Tang et al., 2006. Agri. For. Met., in press
Sap flow vs. tower measurement of water flux
Tang et al., 2006. J. Geophys. Res.-Biogeosciences
EC = 65% ET in the growing season
ET (mm day-1)
0 1 2 3 4 5
EC (
mm
day
-1)
0
1
2
3
4
5
No rain Rain
No rain: y = 1.80x0.41, r2 = 0.55
Rain: y = 1.03x, r2 = 0.65
D (kPa)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
WU
E (
mg
g-1
)
0
5
10
15
20
25
30
y = 4.40 + 15.69e-5.94x
r2 = 0.72, p< 0.0001
Water use efficiency (WUE = GPP/EC) response to D (VPD)
Tang et al., 2006. J. Geophys. Res.-Biogeosciences
Work in progress
Diurnal patterns of soil respiration
Year 2005
• Validate nighttime eddy covariance data, and correspondingly, daytime GPP;• Parameterize the soil respiration model.
Time
0 2 4 6 8 10 12 14 16 18 20 22 24
Flu
x (
mol
m-2
s-1
)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4Riley Creek May 2, 2006 Year 2006
Time of Day
15 20 25 30 35 40 45
Flu
x (
mol
m-2
s-1)
1
2
3
4
5
6
7
Lost D207 Ameba D208 Willow D209
July