Family: Myrtaceae

Origin, Description & Uses:
Eucalyptus robusta, commonly known as swamp mahogany, is native to eastern Australia. It is a tall evergreen tree that can grow up to 30 meters (about 100 feet) in height and is recognized by its rough, fibrous bark and glossy, lance-shaped leaves. The tree produces clusters of creamy white flowers that attract bees and other pollinators. Swamp mahogany is valued for its durable timber, which is used in construction, furniture, and fencing, and it is also planted for shade, windbreaks, and erosion control in wet or poorly drained soils. Its adaptability to moist conditions makes it a practical choice for landscaping in tropical regions.

Risks & Threats:
In Hawaii, Eucalyptus robusta is naturalized but is considered low risk. While it grows well in wet areas, it does not generally spread aggressively beyond cultivation. There are minimal ecological concerns associated with this species compared to higher-risk Eucalyptus species. However, like all non-native trees, it’s important to monitor planting locations to prevent potential impacts on native plant communities. Choosing native or low-risk alternatives for sensitive habitats is always recommended to support local biodiversity.

High Risk Traits:

• Naturalized in Hawaiʻi: Kauaʻi, Oʻahu, Molokaʻi, Lanaʻi, Maui, Hawaiʻi
  
• Self-compatible: Reproduces via self-pollination
  
• Prolific, wind-dispersed seeds: ~452,000 viable seeds/kg
  
• Broad soil tolerance: Grows in clays, sands, saline, and waterlogged soils
  
• Fire-adapted: Recovers well after fire
  
• Unpalatable to livestock: Low palatability for browsing animals
  
• Congeneric weeds: Other Eucalyptus species are weedy in Australia
  
• Susceptible to pests: Host for Cylindrocladium stem canker

Low Risk Traits:

• Slow to mature: Flowers in 2–5 years
  
• Shade-intolerant: Requires full sun
  
• No evidence of dense thicket formation
  
• No toxicity to animals or humans reported