Canopy Dynamics of Eucalyptus maculata Hook. II. Canopy Leaf Area Balance

Abstract

The leaf area balance of a regenerated stand of E. maculata was monitored for a period of 2½ years on the basis of repetitive non-destructive measurements of production and loss of leaf area in sample branches of a group of trees representative of the forest. Leaf area loss measured in sample tree canopies was closely correlated with forest leaf fall (litter) and verified the phenological harmony between the sample group and the forest. Production and loss of leaf area from sample trees were scaled to the mean annual forest leaf fall to estimate production and loss at forest dimensions.

Basal area of E. maculata tree bole was closely correlated with canopy leaf area. Basal area ratio (sample/forest) remained constant and was used to adjust sample group leaf area (determined by direct measurement) to forest dimensions for calculation of the forest leaf area balance.

Basal area as an estimator of leaf area was insensitive to seasonal variations but provided a valuable reference datum. Leaf area index (LAI) of the eucalypt overstorey determined from basal area virtually remained unchanged. LAI of forest eucalypts estimated from the detailed leaf area balance fluctuated between 2.65 and 3.12. Maximum values of LAI were attained at the peak of growth seasons when rates of leaf production were high relative to leaf loss. Estimated annual production and loss of leaf area were not equal.