Net carbon storage in a poplar plantation (POPFACE) after three years of free-air CO2 enrichment.
A high-density plantation of three genotypes of Populus was exposed to an elevated concentration of carbon dioxide ([CO(2)]; 550 micromol mol(-1)) from planting through canopy closure using a free-air CO(2) enrichment (FACE) technique. The FACE treatment stimulated gross primary productivity by 22 and 11% in the second and third years, respectively. Partitioning of extra carbon (C) among C pools of different turnover rates is of critical interest; thus, we calculated net ecosystem productivity (NEP) to determine whether elevated atmospheric [CO(2)] will enhance net plantation C storage capacity. Free-air CO(2) enrichment increased net primary productivity (NPP) of all genotypes by 21% in the second year and by 26% in the third year, mainly because of an increase in the size of C pools with relatively slow turnover rates (i.e., wood). In all genotypes in the FACE treatment, more new soil C was added to the total soil C pool compared with the control treatment. However, more old soil C loss was observed in the FACE treatment compared with the control treatment, possibly due to a priming effect from newly incorporated root litter. FACE did not significantly increase NEP, probably as a result of this priming effect.
Gielen
B
B
University of Antwerpen, Campus Drie Eiken, Dept. of Biology, Research Group of Plant and Vegetation Ecology, Wilrijk, Belgium. birgit.gielen@ua.ac.be
Calfapietra
C
C
Lukac
M
M
Wittig
V E
VE
De Angelis
P
P
Janssens
I A
IA
Moscatelli
M C
MC
Grego
S
S
Cotrufo
M F
MF
Godbold
D L
DL
Hoosbeek
M R
MR
Long
S P
SP
Miglietta
F
F
Polle
A
A
Bernacchi
C J
CJ
Davey
P A
PA
Ceulemans
R
R
Scarascia-Mugnozza
G E
GE
D018533:Biomass; D002245:Carbon Dioxide; D018517:Plant Roots / Q000502:physiology; D032107:Populus / Q000502:physiology*; D012987:Soil; D014197:Trees / Q000502:physiology*
D012987:Soil; D002245:Carbon Dioxide