Family: Myrtaceae

Origin, Description & Uses:
Eucalyptus cloeziana, commonly known as Queensland messmate, is a tall hardwood tree native to eastern Australia, particularly Queensland and parts of New South Wales. It typically grows straight and upright, with a dense crown and rough, fibrous bark along the trunk. The leaves are lance-shaped and aromatic, as is characteristic of many eucalyptus species, and the tree produces small white flowers that attract pollinators. Queensland messmate is highly valued for its strong, durable timber, which is resistant to decay and termites, making it a popular choice for construction, poles, flooring, and outdoor applications. It is also occasionally planted in forestry operations and as a windbreak or shade tree in suitable climates.

Risks & Threats:
This species is considered low risk in Hawaiʻi and similar tropical regions, as it has not shown a tendency to spread aggressively or become invasive. While it produces seeds, natural regeneration outside of managed plantings is limited. As with other eucalyptus species, it may pose minor concerns such as increased leaf litter or competition for water in certain settings, but these impacts are generally localized and manageable. Overall, Eucalyptus cloeziana is unlikely to pose significant ecological threats when properly sited and maintained.

High Risk Traits:

• Broad climate suitability (elevation 0-1500 m; rainfall 500-2300 mm)
  
• History of repeated introductions outside native range
  
• Congeneric weeds present (other Eucalyptus species are weedy)
  
• Tolerates partial shade
  
• Produces viable seed
  
• Capable of natural hybridization
  
• Propagules dispersed intentionally by people
  
• Propagules adapted for wind dispersal
  
• Tolerates fire, drought, and coppices

Low Risk Traits:

• No evidence of naturalization or weediness
  
• No spines, thorns, or burrs
  
• Not allelopathic, parasitic, or toxic
  
• Predominantly outcrossing (not self-compatible)
  
• No vegetative reproduction
  
• Long minimum generative time (approx. 9 years)
  
• No evidence of accidental or animal-mediated dispersal