Free access
Issue
Ann. For. Sci.
Volume 48, Number 2, 1991
Page(s) 225 - 234
DOI http://dx.doi.org/10.1051/forest:19910209
Ann. For. Sci. 48 (1991) 225-234
DOI: 10.1051/forest:19910209

Variations de la croissance radiale de Quercus ilex L en fonction du climat

SH Zhang and F Romane

CNRS, centre Emberger, BP 5051, 34033 Montpellier cedex 1, France

Résumé - La croissance radiale du chêne vert (Quercus ilex L), espèce dominante dans beaucoup de formations végétales du Bassin méditerranéen, est étudiée en relation avec les précipitations et les températures. L'analyse (analyses factorielles, procédure ARMA, etc) permet de montrer que l'existence des faux cernes, phénomène fréquent chez cette espèce, est favorisée par des précipitations estivales. L'épaisseur des cernes est aussi liée positivement aux précipitations estivales, alors que les températures des mois d'octobre à décembre précédant la saison de croissance sont liées négativement à cette épaisseur. Cette espèce est donc capable de profiter des précipitations estivales, alors qu'elle paraît «indifférente» aux conditions climatiques printanières, c'est-à-dire à celles de la phase principale de croissance.


Abstract - Diameter growth of Quercus ilex L and the interannual variability of climatic characteristics. Diameter growth of Quercus ilex L, the dominant sclerophyllous species in much of the Mediterranean basin vegetation, was studied in relation to precipitation and temperature. The study site in Montpellier (Southern France) has a Mediterranean climate. Eleven trees, grown from acorns in 1963, were cut in 1984 and the rings studied at 3 levels (ground, 0.5 and 1 m above the ground). The data were analyzed by the ARMA procedure which gives the part of the total variation due to the autocorrelation processes. A multiple regression between the factors of a principal component analysis (PCA) of the monthly climatic data (rainfall and temperature) and the residuals issuing from the ARMA procedure then suggested that the large annual rings were due to a particular rainfall distribution during the year, the late summer precipitation promoting a large annual growth diameter (table II). The presence or absence of false rings (table I) was also analyzed by PCA (figs 2 and 3). The false rings were positively correlated to a large annual growth diameter corresponding to a high summer rainfall (fig 4), while the relationship with the temperature preceding the growing season was negative. It therefore appears that this species is relatively unaffected by spring climatic conditions, ie which generally indicate the main growth phase, but that it is able to take advantage of the interannual climatic variations of the region.


Key words: ring / Mediterranean climate / diameter growth / precipitation / Quercus ilex L / temperature

Mots clés : cerne / climat méditerranéen / croissance radiale / précipitations / Quercus ilex L / température