Foliage projective covers of overstorey and understorey strata of mature vegetation in Australia

At maturity, both overstorey and understorey foliage projective covers (FPC) tend to reach steady‐state values which are correlated with the evaporative coefficient (k) in the water balance equation of the soil‐plant‐atmosphere continuum. Overstorey FPCs of mature communities increase linearly from 20 to 85% along the moisture gradient from arid to humid regions. Understorey FPCs in mature communities are relatively constant along the same moisture gradient, increasing only slightly from 40 to 47%. Plant communities which have overstorey FPCs different from the norm, appear to show a compensatory decrease or increase in understorey FPC so that the sum of the FPCs of overstorey and understorey is equal to that predicted for the region.