Canopy Dynamics of Eucalyptus maculata Hook. III Effects of Drought

Abstract

The severe 7-month drought in coastal and adjacent tablelands regions of New South Wales in the latter half of 1980 caused heavy leaf-shedding, wilting of persistent foliage and bark-splitting in forest eucalypts. Defoliation of individual sample trees of E. maculata ranged from 50 to 97% of pre-drought leaf area. Leaf area index of a stand of E. maculata was reduced from c. 4.3 to 0.8. E. maculata was less susceptible to drought than E. globoidea and E. pilularis but more susceptible than E. Paniculata in mixed forest on the same site.

Rapid recovery of the canopy occurred in autumn after the break of the drought and leaf areas of all sample trees attained pre-drought values or above by summer 1981-82.

Leaf-shedding in response to severe water deficit appears to have been of adaptive significance in enhancing tree survival in a drought of this duration.