C-LAMP Free Air CO₂ Enrichment (FACE) Simulations

Forrest Hoffman and Jim Randerson
Updated September 9, 2008

Background

Websites

• Aspen FACE Experiment
• Duke University FACE Experiment
• EuroFACE
• Oak Ridge Experiment on CO₂ Enrichment of Sweetgum

Papers

• Norby et al., 2005, Forest response to elevated CO₂ is conserved across a broad range of producitivty
• Hickler et al., 2008, CO₂ fertilization in temperate FACE experiments not representative of boreal and tropical forests
• McMurtrie et al., 2008, Why is plant-growth response to elevated CO₂ amplified when water is limiting, but reduced when nitrogen is limiting? A growth-optimisation hypothesis
• Iversen et al., 2008, Nitrogen limitation in a sweetgum plantation: implications for carbon allocation and storage

C-LAMP Experiment Descriptions

• Experiment 1.6: Free Air CO₂ Enrichment (FACE) control run
• Experiment 1.7: Free Air CO₂ Enrichment (FACE) transient run

Global FACE Analysis

Dynamics of Global Carbon Fluxes

Net Primary Production (NPP)

Net Ecosystem Exchange (NEE)

Number of Grid Cells	Plant Functional Type	CASA′ Model									CN Model
		Exp 1.6, 1997-2001			Exp 1.7, 1997-2001			Difference			Exp 1.6, 1997-2001			Exp 1.7, 1997-2001			Difference
		NPP (gC m-2 y-1)		Total NPP (PgC y-1)	NPP (gC m-2 y-1)		Total NPP (PgC y-1)	NPP mean increase	βL	Total NPP (PgC y-1)	NPP (gC m-2 y-1)		Total NPP (PgC y-1)	NPP (gC m-2 y-1)		Total NPP (PgC y-1)	NPP mean increase	βL	Total NPP (PgC y-1)
		mean	standard deviation		mean	standard deviation					mean	standard deviation		mean	standard deviation
676	not vegetated	58.43	104.49	2.75	73.73	128.15	3.50	26.19%	0.65	0.76	29.45	84.59	1.48	33.26	93.65	1.67	12.96%	0.32	0.19
38	needleleaf evergreen temperate tree	1332.66	328.49	2.35	1539.69	402.22	2.73	15.54%	0.38	0.38	659.92	148.90	1.22	713.97	160.46	1.32	8.19%	0.20	0.10
150	needleleaf evergreen boreal tree	641.27	135.69	4.80	723.73	145.03	5.44	12.86%	0.32	0.65	277.17	84.89	2.10	300.10	90.62	2.28	8.27%	0.20	0.18
0	needleleaf deciduous boreal tree
164	broadleaf evergreen tropical tree	2186.85	231.90	25.39	2506.13	241.76	29.19	14.60%	0.36	3.80	1178.80	210.14	14.04	1321.25	218.96	15.71	12.08%	0.30	1.66
16	broadleaf evergreen temperate tree	1400.37	397.32	0.95	1563.87	478.89	1.08	11.68%	0.29	0.13	851.02	213.40	0.59	906.69	226.41	0.63	6.54%	0.16	0.04
10	broadleaf deciduous tropical tree	1571.34	227.32	1.12	1891.29	254.09	1.35	20.36%	0.50	0.23	842.76	284.36	0.62	951.57	322.27	0.70	12.91%	0.32	0.08
15	broadleaf deciduous temperate tree	1039.47	200.82	1.02	1222.67	236.40	1.20	17.63%	0.44	0.18	710.09	161.24	0.71	770.46	161.17	0.77	8.50%	0.21	0.06
0	broadleaf deciduous boreal tree
0	broadleaf evergreen shrub
64	broadleaf deciduous temperate shrub	350.97	223.33	1.65	450.51	271.65	2.12	28.36%	0.70	0.47	102.26	86.50	0.49	114.51	105.55	0.55	11.98%	0.30	0.06
347	broadleaf deciduous boreal shrub	166.51	104.47	2.00	185.88	114.74	2.26	11.63%	0.29	0.26	34.19	70.17	0.40	35.20	72.10	0.41	2.94%	0.07	0.01
165	c3 arctic grass	391.84	144.57	2.55	442.15	155.00	2.93	12.84%	0.32	0.38	142.44	100.24	0.91	150.96	105.77	0.97	5.98%	0.15	0.06
449	c3 non-arctic grass	783.91	431.15	20.76	939.50	500.00	25.10	19.85%	0.49	4.35	374.29	237.79	10.00	410.56	253.82	10.97	9.69%	0.24	0.97
341	c4 grass	1371.54	514.75	25.25	1608.62	571.96	29.67	17.29%	0.43	4.42	517.30	342.57	9.50	576.19	384.98	10.56	11.38%	0.28	1.06
71	corn	818.24	280.34	4.04	970.73	319.56	4.81	18.64%	0.46	0.77	488.09	195.36	2.41	515.54	203.15	2.54	5.62%	0.14	0.13
0	wheat
3492	Global	464.30	646.36	94.62	542.89	747.65	111.37	16.93%	0.42	16.75	210.08	334.92	44.46	231.61	371.18	49.07	10.25%	0.25	4.60
1830	All Vegetated	864.40	675.38	91.87	1008.70	776.86	107.87	16.69%	0.41	16.00	390.00	378.45	42.99	429.66	420.74	47.40	10.17%	0.25	4.41
393	Forests	1422.87	730.17	35.63	1629.38	839.23	40.99	14.51%	0.36	5.36	744.71	437.78	19.29	825.47	491.13	21.41	10.84%	0.27	2.12
411	Shrubs	195.23	146.14	3.65	227.09	177.99	4.38	16.32%	0.40	0.73	44.79	76.91	0.89	47.55	83.24	0.96	6.15%	0.15	0.07
955	Grasses	925.99	561.36	48.56	1092.49	646.15	57.70	17.98%	0.44	9.14	385.30	294.26	20.41	424.85	325.97	22.50	10.27%	0.25	2.09
71	Crops	818.24	280.34	4.04	970.73	319.56	4.81	18.64%	0.46	0.77	488.09	195.36	2.41	515.54	203.15	2.54	5.62%	0.14	0.13
69	Temperate Forests	1284.62	345.74	4.32	1476.38	410.32	5.01	14.93%	0.37	0.69	715.14	183.07	2.52	770.94	191.87	2.72	7.80%	0.19	0.20
174	Tropical Forests	2151.47	272.02	26.51	2470.79	281.12	30.54	14.84%	0.37	4.02	1159.49	227.96	14.67	1300.00	240.87	16.41	12.12%	0.30	1.74
150	Boreal Forests	641.27	135.69	4.80	723.73	145.03	5.44	12.86%	0.32	0.65	277.17	84.89	2.10	300.10	90.62	2.28	8.27%	0.20	0.18

Global Maps of Net Primary Production (NPP) Response

Net Primary Production (NPP) for Control Run (Experiment 1.6)

Net Primary Production (NPP) for Transient Run (Experiment 1.7)

Difference in Net Primary Production (NPP) for Transient-Control (Experiment 1.7-Experiment 1.6)

Percent Change in Net Primary Production (NPP) Between Transient and Control

βL Response Between Transient and Control

Zonal Mean Net Primary Production (NPP) Response

Zonal Mean Net Primary Production (NPP) Data: zonal_mean_npp.dat

Dynamics of Global Carbon Stocks

Leaf Carbon

Wood Carbon

Fine Root Carbon

Coarse Woody Debris Carbon

Litter Carbon Note: The sudden drop in litter carbon in the CASA′ simulations is due to the reassignment of a microbial pool from the litter group to the soil group in 1997.

Soil Carbon Note: The sudden rise in soil carbon in the CASA′ simulations is due to the reassignment of a microbial pool from the litter group to the soil group in 1997.

Site Net Primary Production (NPP) Response

Site Name	Longitude (°E)	Latitude (°N)	Measurement		CASA′ Model			CN Model
			NPP Increase	βL	NPP Increase	βL	Score	NPP Increase	βL	Score
DukeFACE	-79.08333	35.96666	28.0%	0.69	16.4%	0.41	0.26	6.2%	0.15	0.65
AspenFACE	-89.61666	45.66666	35.2%	0.87	15.6%	0.39	0.39	12.4%	0.31	0.48
ORNL-FACE	-84.33333	35.90000	23.9%	0.59	17.3%	0.43	0.16	5.2%	0.13	0.64
POP-EUROFACE	11.80000	42.36666	21.8%	0.54	20.0%	0.49	0.04	5.7%	0.14	0.59
4 Site Mean			27.2%	0.67	17.3%	0.43		7.4%	0.18
Total M Score							0.79			0.41

Sites on Global NPP Percent Change and β_L Response Maps

Percent Change in Net Primary Production (NPP) Between Transient and Control

βL Response Between Transient and Control

FACE Site and Corresponding Grid Cell Characterization

Site Name	Longitude (°E)	Latitude (°N)	Overstory Vegetation	Nearest Longitude (°E)	Nearest Latitude (°N)	Plant Functional Types
DukeFACE	-79.08333	35.96666	Evergreen loblolly pine (Pinus taeda L.)	281.25000	34.88252	1.1% not vegetated 33.1% needleleaf evergreen temperate tree 14.5% broadleaf deciduous temperate tree 0.4% broadleaf deciduous temperate shrub 20.2% c3 non-arctic grass 11.4% c4 grass 19.3% corn
AspenFACE	-89.61666	45.66666	Multispecies assemblage dominated by Populus spp. (Populus tremuloides Michx., Acer saccharum Marsh., Betula papyrifera Marsh.)	270.00000	46.04473	4.5% not vegetated 15.3% needleleaf evergreen temperate tree 1.9% needleleaf evergreen boreal tree 30.8% broadleaf deciduous temperate tree 2.7% broadleaf deciduous boreal tree 24.2% c3 non-arctic grass 1.6% corn
ORNL-FACE	-84.33333	35.90000	Deciduous sweetgum (Liquidambar styraciflua L.)	275.62500	34.88252	23.3% needleleaf evergreen temperate tree 0.1% needleleaf evergreen boreal tree 28.9% broadleaf deciduous temperate tree 0.1% broadleaf deciduous boreal tree 26.3% c3 non-arctic grass 8.3% c4 grass 13.0% corn
POP-EUROFACE	11.80000	42.36666	Multispecies assemblage dominated by Populus spp. (Populus alba L., P. nigra L., P × euramericana Dode Guinier)	11.25000	43.25420	2.2% not vegetated 13.3% needleleaf evergreen temperate tree 0.3% needleleaf evergreen boreal tree 11.0% broadleaf deciduous temperate tree 0.8% broadleaf deciduous boreal tree 3.8% broadleaf deciduous temperate shrub 0.6% c3 arctic grass 40.8% c3 non-arctic grass 5.2% c4 grass 22.1% corn