Family: Myrtaceae
Eucalyptus camaldulensis, (red river gum or red gum) is a large evergreen tree native to Australia. In its native habitat, it plays a crucial ecological role, providing habitats for bats, snakes, and birds. The tree’s debris contributes to important fish habitats along riverbanks. Additionally, it serves as a timber source in plantations and a honey source for beekeepers. Introduced to Hawaiʻi in the 1800s, it was first planted in Ulupalakua, Maui, and Eucalyptus Ridge on Tantalus Mountain, Oʻahu, becoming one of the most commonly planted Eucalyptus trees in the islands. The Division of Forestry planted 429,000 trees by 1960, and more were added by private landowners. It has been declared invasive in several locations, including South Africa, California, Jamaica, Spain, and Hawaiʻi. It has naturalized on the islands of Kauai, Oʻahu, Molokai, Maui, and Hawaiʻi. It poses challenges in the environment due to its flammability, rapid maturation, and self-fertilizing properties.
High Risk Traits:
- Broad climate suitability
- Grows, and spreads, in regions with tropical climates
- Naturalized on Kauai, Oahu, Molokai, Maui, and Hawaii (Hawaiian Islands), and elsewhere
- An environmental weed in South Africa, invading and modifying riparian habitats
- Other Eucalyptus species are invasive
- Allelopathic
- Highly flammable (may increase fire risk)
- Tolerates many soil types
- Reproduces by seeds
- Hybridizes with other Eucalyptus species
- Capable of selfing (with reduced seed set)
- Reaches maturity in 3 years
- Seeds dispersed by water, wind and intentionally by people
- Coppices after cutting, but reported to be killed by fire
Low Risk Traits:
- Despite widespread planting and naturalization, not reported as an environmental weed in the Hawaiian Islands
- Unarmed (no spines, thorns, or burrs)
- May be browsed by animals if other foods are unavailable
- Thrives in full sun (dense shade may limit ability to establish and spread)
- Not reported to spread vegetatively
- Forms a small short-lived seed bank
