Figure 2 . Vegetation PCA biplots. (A ) PCA biplot of
all study trees (N = 72) classified by Treatment. (B ) PCA
biplot of control trees (N = 24) classified by Farm. The ellipses show
the 95% confidence variance for the mean value. The first PCA separates
trees the from different treatments: low cover of short grass (Control),
high cover of short/medium height grass (one-year exclusion), and high
cover of high grass (ten-years exclusion). The second PCA (only control
trees) segregates the three farms on basis of their vegetation at their
standard livestock densities. Variable arrows are displayed to show
differences in grass cover height between farms.