Data from: Morphological and moisture availability controls of the leaf area-to-sapwood area ratio: analysis of measurements on Australian trees

1. The leaf area-to-sapwood area ratio (LA:SA) is a key plant trait that
links photosynthesis to transpiration. The pipe model theory states that
the sapwood cross-sectional area of a stem or branch at any point should
scale isometrically with the area of leaves distal to that point.
Optimization theory further suggests that LA:SA should decrease toward
drier climates. Although acclimation of LA:SA to climate has been reported
within species, much less is known about the scaling of this trait with
climate among species. 2. We compiled LA:SA measurements from 184 species
of Australian evergreen angiosperm trees. The pipe model was broadly
confirmed, based on measurements on branches and trunks of trees from one
to 27 years old. Despite considerable scatter in LA:SA among species,
quantile regression showed strong (0.2 < R1 < 0.65) positive
relationships between two climatic moisture indices and the lowermost (5%)
and uppermost (5–15%) quantiles of log LA:SA, suggesting that moisture
availability constrains the envelope of minimum and maximum values of
LA:SA typical for any given climate. 3. Interspecific differences in plant
hydraulic conductivity are probably responsible for the large scatter of
values in the mid-quantile range and may be an important determinant of
tree morphology.