Growth of a poplar short rotation coppice under elevated atmospheric CO2 concentrations (EUROFACE) depends on fertilization and species

Abstract

Growth and woody biomass production of three Populus species (P. nigra L. clone Jean Pourtet, P. alba L. clone 2AS-11 and P. x euramericana clone I-214), were followed during the first growing season after coppice of a short rotation coppice culture exposed to elevated atmospheric CO2 concentrations by means of Free-Air Carbon dioxide Enrichment (FACE), and to a nitrogen (N) fertilization treatment. FACE significantly increased the number of shoots per stool, but did not significantly increase height nor total basal area per stool. In September, FACE significantly increased the Leaf Area Index (LAI) with 5.5 to 16.4%, depending on species. FACE significantly stimulated the woody biomass production by up to 25%, but the stimulation of P. alba and P. x euramericana was restricted to the fertilized treatment. Significant differences between species were observed. We concluded that coppice diminished the FACE effect, that the positive FACE effect was restricted under lower soil fertility, and that species differed in their response to FACE.