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. euramericana clone I-214), were followed during the first growing season after coppice of a short rotation coppice culture exposed to elevated atmospheric CO 2 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. 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. free-air carbon dioxide enrichment / N-fertilization / short rotation coppice culture / Populus / growth Rsum -La croissance de taillis de peuplier courte rotation dans une atmosphre concentration en CO 2 leve dpend de la fertilisation et de l'espce. La croissance et la production ligneuse de biomasse de trois espces de peuplier (Pinus nigra L. clone J. Pourtet, P. alba L. clone 2AS-11 et P. euramericana clone I-214) ont t suivies pendant la premire saison de croissance aprs la coupe du taillis courte rotation expos une concentration leve en CO 2 , au moyen d'un systme FACE et une fertilisation azote. Le FACE accrot significativement le nombre de pousses par pied. En septembre, le FACE a augment l'indice foliaire (LAI) de 5,5 16,4 % selon les espces. FACE stimule significativement la production de biomasse ligneuse (25 %) mais pour P. alba et P. euramericana cette stimulation ne concerne que le traitement fertilis. Des diffrences significatives ont t observes entre les espces. Nous concluons que le taillis amoindrit l'effet du FACE, que l'effet positif du FACE tait limit pour un sol peu fertile et que les espces diffrent dans leur rponse au FACE.