The leaf economics spectrum
Mass-based leaf traits
The six mass-basis leaf traits varied by one to two orders of magnitude
across the data set. LMA ranged from 14 to 1,500 gm22 and
LL from 0.9 up to 288 months. Amass ranged from 5 to
660 nmol g21 s21; dark respiration from 2.2 to 65 nmol g21 s21.
Nmass ranged from 0.2 to 6.4%; Pmass from 0.008 to 0.6%. Considered
pairwise, all leaf traits were highly correlated (Table 1).
These correlations have been reported previously from smaller data
sets6–10,23. Here we have generalized the patterns over many more
species, sites and vegetation types.
We moved beyond pairwise consideration of traits to determine
the extent to which leaf economic traits covary in multidimensional
trait space. This covariation can be quantified as the proportion of
total trait variation explained by the first principal axis in a principal
components analysis. In two-trait space, the principal axis is the
long axis of the ellipse resulting from two correlated traits. In threetrait
space, the principal axis is the long axis of an ellipsoid. In multidimensional
trait space, the principal axis describes the main axis of
variation through a hyperellipsoid24. A remarkable 82% of all
variation in Amass, LMA and Nmass across species lay along the
first principal axis in three-trait space (Fig. 2a). Because some of the
residual 18% must be measurement variation, 82% represents a
minimum estimate of the dominance of this single spectrum in
explaining variation across plant species worldwide. Further threedimensional