how big is it?
It varies in size.
Eucalyptus
Eucalypts vary in size and habit from shrubs to tall trees. 
where do you find australian green tree frog? Australia and New Guinea does it has any scientific name? Yes, "Ranoidea caerulea". is it under any threat or needs to be conserved? Yes, it is a threat in suburban areas by pollution and by predation by domestic animals. in which research is it used? UNANSWERABLE where is the above mentioned latter place situated? It is located in Melanesia in the southwestern Pacific Ocean. what other kind of wild life or plant life does it support? The flora includes  "Podocarpus", "Araucaria" and "Agathis," and several species of "Eucalyptus". is there any hybrids available of the last one? Yes, "E. chrysantha",  "E. rivalis" and  "E. erythrandra".
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Eucalyptus [SEP] Size and habit
Eucalypts vary in size and habit from shrubs to tall trees. Trees usually have a single main stem or trunk but many eucalypts are mallees that are multistemmed from ground level and rarely taller than . There is no clear distinction between a mallee and a shrub but in eucalypts, a shrub is a mature plant less than tall and growing in an extreme environment. "E. vernicosa" in the Tasmanian highlands, "E. yalatensis" on the Nullarbor and "E. surgens" growing on coastal cliffs in Western Australia are examples of eucalypt shrubs. The terms "mallet" and "marlock" are only applied to Western Australian eucalypts.