Elevated CO2 concentration, fertilization and their interaction: growth stimulation in a short-rotation poplar coppice (EUROFACE).
We investigated the individual and combined effects of elevated CO2 concentration and fertilization on aboveground growth of three poplar species (Populus alba L. Clone 2AS-11, P. nigra L. Clone Jean Pourtet and P. x euramericana Clone I-214) growing in a short-rotation coppice culture for two growing seasons after coppicing. Free-air carbon dioxide enrichment (FACE) stimulated the number of shoots per stool, leaf area index measured with a fish-eye-type plant canopy analyzer (LAIoptical), and annual leaf production, but did not affect dominant shoot height or canopy productivity index. Comparison of LAIoptical with LAI estimates from litter collections and from allometric relationships showed considerable differences. The increase in biomass in response to FACE was caused by an initial stimulation of absolute and relative growth rates, which disappeared after the first growing season following coppicing. An ontogenetic decline in growth in the FACE treatment, together with strong competition inside the dense plantation, may have caused this decrease. Fertilization did not influence aboveground growth, although some FACE responses were more pronounced in fertilized trees. A species effect was observed for most parameters.
Liberloo
Marion
M
Research Group of Plant and Vegetation Ecology, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium. marion.liberloo@ua.ac.be
Dillen
Sophie Y
SY
Calfapietra
Carlo
C
Marinari
Sara
S
Luo
Zhi Bin
ZB
De Angelis
Paolo
P
Ceulemans
Reinhart
R
D018533:Biomass; D002245:Carbon Dioxide; D005308:Fertilizers; D018515:Plant Leaves / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D032107:Populus / Q000254:growth & development*; D014197:Trees / Q000254:growth & development*
D005308:Fertilizers; D002245:Carbon Dioxide