References 1. Zhang F.M., J.M. Chen, Y. Pan, R. A. Birdsey, S.H. Shen, W.M Ju, and L.M. He,...
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Transcript of References 1. Zhang F.M., J.M. Chen, Y. Pan, R. A. Birdsey, S.H. Shen, W.M Ju, and L.M. He,...
References 1. Zhang F.M., J.M. Chen, Y. Pan, R. A. Birdsey, S.H. Shen, W.M Ju, and L.M. He, Attributing carbon sinks in conterminous US forests to disturbance and non-disturbance factors from 1901 to 2010, Journal of Geographical Research, 2012, 117, doi:10.1029/2011JG001930.
2. Chen, W., J. M. Chen, and J. Cihlar (2000a), Integrated terrestrial ecosystem carbon-budget model based on changes in disturbance, climate, and atmospheric chemistry, Ecological Modelling, 135, 55-79.
3. Balshi, M. S., A. D. McGuire, P. Duffy, et al. (2009), Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century, Global Change Biology, 15, 1491-1510.
4. Balshi, M. S., A. D. McGuire, Q. Zhuang, et al. (2007), The role of historical fire disturbance in the carbon dynamics of the pan-boreal region: A process-based analysis. J. Geophys. Res, 112, G02029, doi:10.1029/2006JG000380.
Fangmin Zhang1, Jing M. Chen1, Richard A. Birdsey2, and Yude Pan2
1. Department of Geography, University of Toronto, 100 St. George Street, Room 5047, Toronto, Ontario M5S 3G3, Canada;2. Newtown Square Corporate Campus, USDA Forest Service, 11 Campus Blvd, Newtown Square, PA 19073, United States
( , , ) ( , , ) ( , , ) ( , , )
( , , ) ( , , ) ( , , ) / ( , , )wc cru cru
wc cru cru
T i j m T i j m T i j m T i j m for temperature
R i j m R i j m R i j m R i j m for precipitation
26
Future carbon stock changes of US forests with consideration of climate, atmospheric composition, disturbance and age effects
Stand age and disturbances are recognized as important factors influencing the short- and long- term forest C dynamics. In addition to these factors, climate, CO 2 and nitrogen deposition have had significant direct and indirect effects on C dynamics of US forests. Future C dynamics will continue to be affected by these factors, which should be considered in developing optimum forest management policies. We used the Integrated Terrestrial Ecosystem Carbon Model to project how these factors will affect US forest C stocks under the IPCC A2 and B2 future climate scenarios and three disturbance scenarios: (1) forest stand ages are fixed in 2010 and no disturbances would occur after 2010 (D fixedage), (2) forest stands are aging with no new disturbances after 2010 (Daging), and (3) forest disturbed area increases at a fixed annual fraction (1%) and then forest regrowth starts in the second year (D disturbed).
Methodology The Integrated Terrestrial Carbon Cycle Model (InTEC) was designed for the purpose of investigating the effects of changing climate, atmospheric composition, disturbances, and forest recovery on the long-term C and N cycles in forest ecosystems (Chen et al., 2000a, b, c, 2003; Ju et al, 2007; Zhang et al., 2011a, b). The advantage of this model is that it integrates the effects of both non-disturbance (climate, CO2 concentration, N deposition) and disturbance (i.e. direct C loss from harvest, fire and insect attacks, and subsequent forest recovery following disturbance events) on C dynamics.
Disturbance factorsfire, harvest, insect,
stand age
... ( )2nondis N,CO ,climate,f
Net Primary Productivity
(NPP)
, ,( )dis age species disurbancesf
Product C pools
Soil C pools (9)surface structural detritus, surface metabolic detritus, soil structural detritus, soil metabolic detritus,
woody litter, surface microbe, soil microbe, slow carbon, and passive
NEPor
NBP
Climate variabilityCO2 concentrationNitrogen deposition
Non-disturbance factors
Decomposition
Vegetation C pools (4)foliage, woody, fine root, and
coarse root
Harvest
Fig. 1 The framework of Integrated Terrestrial Ecosystem Carbon Model (InTEC).
Assuming disturbances cause stand-replacement, and forests start to recover immediately in the year after disturbances. Forests experience a pulse of C losses in a disturbance year, the remaining biomass C is transferred to woody litter, surface metabolic detritus and surface structural detritus (Chen et al., 2003). After disturbances, forest stands start to regenerate immediately, net C change becomes more positive and reaches a peak as plants regenerate and soil detritus decays.
Future Projections
Scenario I: with fixed age and no disturbances --------Forests will not be disturbed and keep stand age in 2010.
Scenario II : with age change and no disturbances -------Forests will be aging without new disturbances until 2100.
Scenario III: with age change and disturbances ------Forests will be disturbed with new disturbances to 2100. Disturbance rate is 1% per year by regions. Disturbance occurred in oldest forests and followed by younger forests.
Three disturbance scenarios: Two climate scenarios: GCGM2 A2 and B2
0
4
8
12
16
1900 1940 1980 2020 2060 2100
Nitr
ogen
dep
sitio
n(k
g N
ha-1
)
Year
Under A2 climatesUnder B2 climates b
0
200
400
600
800
1900 1940 1980 2020 2060 2100
[CO
2] (p
pmv)
Year
Under A2 climatesUnder B2 climates
a
States
0
b
States
0
d
PrecipitationTemperature
States
0
a
States
0
a
8 7 6 5 4 3 2
OC States
0
c
oC
B2
A2
Accumulated NBP under A2 climate scenario (2011-2100)
20
80
-1
81Climate
N+CO2
Total (22 Pg C)
Dis.
Non-dis.
%-9
109
11
99Climate
N+CO2
North (5 Pg C)
Dis.
Non-dis.
%
-40
140
-13
152Climate
N+CO2
Rocky Mountain (2 Pg C)
Dis.
Non-dis.
%
6
94
6
88Climate
N+CO2
West Coast (1 Pg C)
Dis.
Non-dis. %
4060
-5
65Climate
N+CO2
South (14 Pg C)
Dis.
Non-dis.
%
0
States
-10
-5
0
5
20
10
-20
Kg C m-2
West Coast
Rocky MountainNorth
South
Total: 22 Pg C
With age change and disturbances
0
States
-10
-5
0
5
20
10
-20
Kg C m-2
With fixed age and no disturbances
West Coast
Rocky Mountain
North
South
Total: 41 Pg C
6931
-8
39Climate
N+CO2
South (24 Pg C)
Dis. Non-dis.
%
4
96
-6
102Climate
N+CO2
Rocky Mountain (3 Pg C)
Dis.
Non-dis. %
40 60
6
54Climate
N+CO2
West Coast (3 Pg C)
Dis.
Non-dis. %
43 57
6
51Climate
N+CO2
North (11 Pg C)
Dis.
Non-dis.
%
55 45
-3
48
Climate
N+CO2
Total (41 Pg C)Dis.Non-dis.
%
25
75
-9
84Climate
N+CO2
Total (18 Pg C)
Dis.
Non-dis.
%
54 46
-18
65Climate
N+CO2
South (11 Pg C)
Dis. Non-dis.
%
-39
139
-13
152Climate
N+CO2
Rocky Mountain (2 Pg C)
Dis.
Non-dis. %
-42
142
6
136Climate
N+CO2
West Coast (1 Pg C)
Dis.
Non-dis. %
3466
9
57Climate
N+CO2
North (5 Pg C)
Dis.
Non-dis.
%
0
States
-10
-5
0
5
20
10
-20
Kg C m-2
With age change and no disturbances
Total: 18 Pg C
West Coast
Rocky Mountain
North
South
Accumulated NBP under B2 climate scenario (2011-2100)
0
States
-10
-5
0
5
20
10
-20
With age change and no disturbances
Kg C m-2
Total: 13 Pg C
West Coast
Rocky Mountain
North
South
-3
103
2578Climate
N+CO2
North (3 Pg C)
Dis.
Non-dis.
%
6733
-21
54Climate
N+CO2
South (9 Pg C)
Dis. Non-dis.
%
-73
17310
163Climate
N+CO2
West Coast (1 Pg C)
Dis.
Non-dis. %
-77
177
16
161
Climate
N+CO2
Rocky Mountain (1 Pg C)
Dis.
Non-dis. %
34
66
-6
72Climate
N+CO2
Total (13 Pg C)
Dis.
Non-dis.
%
0
States
-10
-5
0
5
20
10
-20
With fixed age and no disturbances
Kg C m-2
Total: 35 Pg C
West Coast
Rocky MountainNorth
South
5149
1237Climate
N+CO2
North (10 Pg C)
Dis.Non-dis.
%
79
21-9
30ClimateN+CO2
South (21 Pg C)
Dis.
Non-dis. %
6
94
11
83Climate
N+CO2
Rocky Mountain (3 Pg C)
Dis.
Non-dis. %
47 53
9
44Climate
N+CO2
West Coast (2 Pg C)
Dis.
Non-dis. %
6535
-1
36Climate
N+CO2
Total (35 Pg C)Dis.
Non-dis. %
27
73
4
69
Climate
N+CO2
Total (17 Pg C)
Dis.
Non-dis.
%
0
States
-10
-5
0
5
20
10
-20
Kg C m-2
With age change and disturbances
West Coast
Rocky Mountain
North
South
-13
113
2786
Climate
N+CO2
North (4 Pg C)
Dis.
Non-dis.
%
51 49
-6
54Climate
N+CO2
South (11 Pg C)
Dis.
Non-dis.
%
9
91
9
83Climate
N+CO2
West Coast (1 Pg C)
Dis.
Non-dis. %
-79
179
17
162
Climate
N+CO2
Rocky Mountain (1 Pg C)
Dis.
Non-dis.
%Total: 17Pg C
Projections for future carbon sinks and sources
0
10
20
30
40
50
2011 2031 2051 2071 2091
Accu
mul
ated
NBP
(Pg C
)
Year
Solid lines are under A2 climate scenarioDot lines are under B2 climate scenario
-1200
-900
-600
-300
0
300
2011 2021 2031 2041 2051 2061 2071 2081 2091
Accu
mul
ated
NBP
(Tg C
)Year
(a) North region
-1200
-900
-600
-300
0
300
2011 2021 2031 2041 2051 2061 2071 2081 2091
Accu
mul
ated
NBP
(Tg C
)
Year
With age change and no disturbancesWith fixed age and no disturbancesWith age change and disturbances
A22 climates
B22 climates
-200
0
200
400
600
800
2000 2020 2040 2060 2080 2100
NBP
(Tg C
yr-1
)
Year
Under A2 climate scenario
-200
0
200
400
600
800
2000 2020 2040 2060 2080 2100
NBP
(Tg C
yr-1
)
Year
Under B2 climate scenario
Preliminary ResultsResults showed that age and disturbance effects would continue to have important roles in determining changes of C stocks. Under both climate scenarios, US forests would be larger C sinks at the end of 21st century than the current level in the 2000s under the Dfixedage and Ddisturbed scenarios. However, US forests would become a smaller C sink or a C source under the Daging scenario. Increasing CO2 and nitrogen deposition enhance the C sink regardless of disturbance scenarios. However, both of these effects would become saturated during the period of 2051-2100 under the Dfixedage scenario. Disturbances and age effects have positive contributions to C accumulation during the period of 2011-2050 and negative contributions during the period of 2051-2100. These results indicate that managing forest stand age structures in appropriate ways could increase C stock accumulation.
Fig. 4 Changes of carbon sinks and
sources of conterminous US
forests in response to two climate and three disturbance scenarios.
Fig. 2 Mean temperature and precipitation anomalies for the period of 2081-2100 relative to the period of
1991-2010.
Fig. 3 Changes of atmospheric CO2 concentration and nitrogen deposition
from 2011-2100.
Fig. 5 Accumulated carbon sinks and
sources of conterminous US
forests in response to two climate and three disturbance scenarios
Fig. 6 Distributions of carbon accumulation conterminous US forests and percentages attributed to the separated effects of disturbance and non-disturbance factors in different regions during 2011-2100 under
A2 climate scenarios and three disturbance scenarios.
Fig. 7 Distributions of carbon accumulation conterminous US forests and percentages attributed to the separated effects of disturbance and non-disturbance factors in different regions during 2011-2100 under
B2 climate scenarios and three disturbance scenarios.