DECIDUOUS QUERCUS IN THE MEDITERRANEAN REGION - TREE-RING CLIMATE RELATIONSHIPS/

Comparisons are made between ring-width response functions relating to precipitation and temperature in 72 Quercus populations (e. afares Po mel, Q. canariensis Willd., Q. pubescens Willd. and and. robur L.) Sit uated in the north and south of the western Mediterranean region. A mu ltivariate procedure applied to the whole set of response functions al lows a distinction to be made of three types of response function acco rding to the species considered. Analogies and differences between cod ed response functions are revealed by the calculation of a mean respon se, firstly for each species and for the genus, secondly for the group s of response functions derived from the multivariate analysis. For al l the populations, and hence for the entire Quercus genus, a direct re sponse to summer precipitation and an inverse response to temperature, especially minimum temperature, are obtained for the summer period. F or the other seasons, each species is characterized by a particular be haviour conditioned by the characteristics of the habitat.