Pet. Ether (65°-69°C) extracts ofEucalyptus olidaL. Johnson et K. Hill leaves and stems from 3-5 year old trees in a trial planting generally contained very high levels (>91% of oil yield) of methyl cinnamate (MC). Some trees had low (0%) or variable levels (0-21%) of MC, highlighting the need to explore selection of proven clones for plantation-scale production of MC. Leaf age and time of harvesting affected MC levels and yields, and also oil yields, which peaked in younger leaves in mid summer. In general, higher MC yields were more closely related to high yields of oil in the foliage rather than high levels of MC in the oil.