Results for grey ironbark showed similarities to spotted gum with regard to the impact of logging, but the species differed markedly in other aspects of nectar production. But not every year is as good as 2005, with flowers measured in 2003 providing a strong contrast.įew trees were in flower and nectarivores, especially birds and honeybees, left virtually no nectar behind by mid-morning.īeekeepers reported that hive bees were not producing honey under these conditions. Honey productivity was found to be comparable across the three different logging histories: recently logged, regrowth and mature. The study surveyed local beekeepers with questionnaires and found that honey yields in 2005 were extremely high: a typical 1000 hectares of spotted gum forest flowering from April-August yielded five tonnes of honey. Most importantly, nectar was not a limited resource in 2005, when the research was undertaken, as extensive flowering was recorded across the south coast. During good seasonal conditions logging history had a marked. However, because current logging practices result in a mosaic landscape, where some areas are logged and others are left untouched, the impact is far less.Īn estimate of nectar production at a ‘compartment’ scale found a recently logged compartment produced half the amount of nectar as a compartment of mature forest. Under drought conditions little nectar was produced per flower regardless of logging history. When the amount of nectar produced by whole forest stands is estimated on the basis of individual flower measurements and counts of flowers and trees, the study found that mature forest produced almost 10 times as much sugar per hectare as recently logged forest. Nectar in flowers bagged overnight was measured to determine how much nectar they produce.īoth large and small trees were measured in forest with different logging histories: recently logged, regrowth and mature (more than 50 years since logging).Īfter measuring thousands of flowers, the study concluded that nectar production in Spotted Gum on a per flower basis was not affected by logging history nor tree size. Using cranes and cherry-pickers, flowers in forest canopies over 30 metres high on the NSW south coast were accessed. The two eucalypt species chosen for research, Spotted Gum Corymbia maculata and Grey Ironbark Eucalyptus paniculata, are of prime importance to nectarfeeding wildlife, the timber industry and beekeepers. Indeed, beekeepers have expressed concern about the effects of logging on nectar production, especially the perception that young trees do not produce as much nectar as mature trees. While Forests NSW has a number of management practices in place to retain nectar-producing trees during logging operations, there has been no information on how much nectar is produced by retained trees or young trees regrowing after logging. State forests provide the major honey resource for the beekeeping industry in NSW.
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