Gum trees have been planted in New Zealand for a long time due to their adaptability, fast growth rate and valuable timber.
With more than 800 species, the Eucalyptus range is diverse for the ornamental garden or arboreta, but usually only a few reliable species are chosen commercially for forestry.
One of the fastest and tallest forestry species is Eucalyptus regnans from Tasmania and Victoria, in southeastern Australia.
In fact, so tall, it is the tallest angiosperm (flowering plant) in the world today, being a similar height to the coniferous Pseudotsuga menziesii, and superseded only by the coast redwood, Sequoia sempervirens.
The tallest Eucalyptus regnans has been named ''Centurion'' by Forestry Tasmania, and measures 99.6m tall, with a girth of 14m.
Taken out of its native habitat Eucalyptus regnans still has the potential to be a giant.
New Zealand's tallest tree is this species and is right on our doorstep, located in the valley at the bottom of Orokonui Ecosanctuary.
About 100 years old, it has now reached a height of over 81m but has the potential to exceed 100m.
Many magnificent, mature specimens of Eucalyptus can be seen in Dunedin Botanic Garden.
Eucalyptus regnans and other potential giants are planted in the arboretum in the upper botanic garden, below the aviary.
• Dylan Norfield is collection curator of the Geographic Collection and Arboretum at Dunedin Botanic Garden.
