  An analysis of data from 212 permanent sample plots provided no evidence of
any decline in rainforest productivity after three cycles of selection logging
in the tropical rainforests of north Queensland. Relative productivity was
determined as the difference between observed diameter increments and
increments predicted from a diameter increment function which incorporated tree
size, stand density and site quality. Analyses of variance and regression
analyses revealed no significant decline in productivity after repeated
harvesting. There is evidence to support the assertion that if any permanent
productivity decline exists, it does not exceed six per cent per harvest.
