Relationships between hydraulic traits and habitat preference for six Acer species occurring in the French Alps

Xylem hydraulic properties and vulnerability to cavitation were studied in six Acer species which occur, in the French Alps, along a soil moisture gradient from the moist valleys to the drier mountain stands. The results obtained suggest that a relationship existed between hydraulic properties and the species moisture preference. Maples located in dry zones (A. opalus, A. monspessulanum) proved more resistant to drought-induced cavitation than species that occurred in an irrigated area (A. negundo, A. pseudoplatanus, A. platanoides, A. campestre). The most vulnerable species to cavitation (A. negundo, A. pseudoplatanus, A. platanoides, A. campestre) showed the highest hydraulic conductances, whereas more cavitation-resistant species (A. opalus, A. monspessulanum) had the lowest conductances. This suggests a trade-off between hydraulic efficiency and cavitation vulnerability. The possible ecological significances of these data are discussed in relation to the distribution of Acer species in their natural habitats.