Vessel diameter and related hydraulic traits of 31 Eucalyptus species arrayed along a gradient of water availability.

We present two comprehensive data sets that describe xylem vessel diameters and related sapwood traits for species of Eucalyptus from arid and semi-arid woodlands and forests in Australia. Between 2009 and 2014, sapwood of mature trees was sampled in south-western, south-eastern and eastern Australia. One additional species was sampled from tropical north-western Australia.

Climate determines vascular traits in the ecologically diverse genus Eucalyptus.

Current theory presumes that natural selection on vascular traits is controlled by a trade-off between efficiency and safety of hydraulic architecture. Hence, traits linked to efficiency, such as vessel diameter, should show biogeographic patterns; but critical tests of these predictions are rare, largely owing to confounding effects of environment, tree size and phylogeny. Using wood sampled from a phylogenetically constrained set of 28 Eucalyptus species, collected from a wide gradient of aridity across Australia, we show that hydraulic architecture reflects adaptive radiation of this genus in response to variation in climate.