First measure of N2O emissions from effluent disposal to Myrtaceae trees. N2O production was 80% lower beneath Kunzea robusta than bare soil areas. K. robusta had 5-fold higher nitrate but aerobic soil limited denitrification. Effluent irrigation to established K. robusta stands may mitigate farm N2O losses. Environmental benefits of reduced N2O emissions warrants further study of Myrtaceae.