Eucalypt, or gum trees, are one of Australia’s most iconic plants, even the scent of their oil evokes the bushland. Eucalypts have had a significant role in shaping our history, culture, landscape and even childhood memories.
The National Herbarium of NSW has a collection of eucalypts (Eucalyptus, Angophora and Corymbia) that would fit comfortably under the shade of one decent sized gum tree. It contains 73,664 specimens, samples of the genetic variation of the eucalypts through time and space.
Through botanists like Joseph Maiden, Lawrie Johnson and Ken Hill the collection has been at the forefront of Eucalypt taxonomy for 120 years. This collection helps to describe many species and our understanding of the relationships between those species. More recently, we have targeted numerous eucalypt species as part of our Restore and Renew project and call on citizen scientists to help us map natural tree hollows for Hollows as Homes. Here are a few reasons why we love eucalypts.
They provide a safe habitat
There are around 300 species in Australia that are reliant on tree hollows for shelter, nests or a temporary resting spot along their journey. Mammals, birds, reptiles, insects and frogs seek out hollows and are particularly fond of eucalypts. Hollow creation is a slow process, especially in Australia where we rely on fungus to eat away at trees rather than an efficient wood pecker. Eucalypts have a long life span allowing more than enough opportunity for a fungi feast helping to create homes for our wildlife.
They are resilient
Eucalypts have evolved to live in dry environments with long dry spells and have many adaptations to withstand fire such as:
- insulated seeds which open only in response to fire
- oils in the leaves help fuel a fire thus making it more intense and detrimental to less fire-adapted species and giving an advantage to eucalypts
- ‘epicormic buds’ under thick bark are ready to sprout new stems and leaves after a fire
- because eucalypts have leaves low in protein and high in toxins they are predated on by few species except the Koala and eucalyptus leaf beetles like the Chrysomelidae.
The diverse flower and fruit
There are over 700 species of eucalypt and their diversity is reflected in the shapes and sizes of their fruits – from large gumnuts of mottlecah, Eucalyptus macrocarpa a Western Australian mallee gum to the tiny capsules of forest giants on the east coast such as the mountain ash, Eucaltyptus regnans.
The brush-like flowers of most Eucalyptus allow open rewards for a wide diversity of animal pollinators, such as insects, birds and mammals. Some Australian species such as E. forrestiana appear to focus exclusively on bird pollinators. Their bizarre long, red, and pendulous flowers make it difficult for insects to access nectar, saving the reward for birds.