Family: Simaroubaceae

Ailanthus excelsa, commonly called Indian tree of heaven or ardu, is a fast-growing deciduous tree native to India and parts of Southeast Asia. It is valued in its home range for timber, shade, and medicinal uses, and is sometimes planted in other regions as a hardy ornamental or for reforestation. The tree can reach impressive heights, with a tall, straight trunk and large, feathery compound leaves. Its ability to tolerate drought, poor soils, and harsh conditions has made it a popular planting choice in arid and semi-arid landscapes.

However, this same resilience could allow Ailanthus excelsa to spread aggressively outside its native range. Related species, such as Ailanthus altissima (tree of heaven), are known to be invasive worldwide, raising concern that Ailanthus excelsa may also pose a risk if widely planted in Hawaiʻi. The tree produces numerous wind-dispersed seeds, grows quickly, and can outcompete native plants in disturbed areas. While not currently naturalized in the Hawaiian Islands, caution is warranted before cultivation to prevent potential ecological impacts.

High Risk Traits:

• Grows in tropical climates
  
• Naturalized in Sudan
  
• Ailanthus altissima has become invasive
  
• Pollen may be allergenic to susceptible individuals
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively by suckers
  
• Seeds dispersed by wind, water and intentionally by people
  
• Able to coppice and resprout after cutting

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Provides fodder for livestock
  
• Ornamental
  
• Light demanding species (may be relatively Shade-intolerant)
  
• Seeds may lose viability in <1 year
  
• Herbicides may provide effective control