Family: Myrtaceae
Origin, Description & Uses
Cider gum (Eucalyptus gunnii) is a fast-growing tree native to southeastern Australia, particularly Tasmania. It is well known for its smooth, peeling bark, rounded silvery-blue juvenile leaves, and tolerance of cooler climates compared to many other eucalyptus species. The tree can reach substantial heights and is often planted as an ornamental for its attractive foliage, as well as for windbreaks, shade, and occasional timber use. It also produces a sweet sap historically used to make a fermented beverage, which gives the tree its common name.
Risks & Threats
Although Eucalyptus gunnii is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that raise concern for tropical island ecosystems. Like many eucalyptus species, it grows rapidly, can outcompete other vegetation, and produces leaf litter that may alter soil chemistry and reduce native plant regeneration. Its high water use and potential to contribute to increased fire risk are additional concerns, particularly in sensitive or drought-prone areas. These characteristics suggest that, if introduced more widely, it could negatively impact native habitats and biodiversity.
High Risk Traits:
- Naturalized in England and New Zealand
- Genus has a reputation for naturalizing and invasiveness
- Forms dense thickets in native range of Tasmania
- Able to hybridize with other Eucalyptus species
- Self-compatible (although vigor is reduced)
- Wind-dispersed seeds
- Seeds persist in capsules on tree for several years
- Resprouts from lignotubers following damage fire or other damage
Low Risk Traits:
- Despite ability to spread, no negative impacts have been documented in introduced range
- Cold climatic requirements may limit the ability to spread in high elevation areas of the tropics
- Palatable to browsing animals (would require protection from ungulates to establish)
- Landscaping and ornamental value
- Juvenile coppice foliage is used in the cut-foliage trade
