Growth rhythms and productivity of a coastal subtropical eucalypt forest

Growth of plant parts in different species in Eucalyptus signata dominated forest in Queensland occurs at different times. Measurement of increments in root basal diameter combined with previously obtained regressions of root weight on root diameter allows separate estimation of the growth of woody root parts on a seasonal basis for the first time. The growth of lateral and of tap roots as well as of stems and leafy twigs, were separately measured on three tree species every 6 weeks for 2 years. Net primary productivity for the forest is estimated at 26 t ha-1 yr-1, of which 66% is aboveground production, and 78% is contributed by a single species. This productivity rate is unexpectedly high, and may reflect a growth stimulus due to release of nutrients following a recent fire.