Family: Pinaceae

Abies concolor, commonly known as silver fir or white fir, is a majestic conifer native to mountainous regions of the western United States and northern Mexico—ranging from the southern Cascades and Sierra Nevada to the Rockies and high-elevation mixed conifer forests. In the wild, it can reach heights of 60 to 200 feet and live for centuries, featuring silvery-blue to green, flattened needles and upright, ornamental cones. In landscape settings, it is prized for its graceful, symmetrical form, attractive foliage, shade tolerance, and adaptability to a variety of soil types and moisture regimes.

In Hawaiʻi, Abies concolor has not shown invasive tendencies. It requires cool winters and is not well suited to lowland tropical conditions. There are no records of it naturalizing in the state or elsewhere in tropical regions. While it is not currently recognized as an invasive threat in Hawaiʻi or other Pacific Islands, its ecological behavior warrants monitoring should it be introduced into new environments.

High Risk Traits:

• Elevation range exceeds 1000 m in temperate climates, demonstrating environmental versatility
  
• Naturalized in New England; possible escape in Denmark
  
• Other Abies species are regarded as invasive
  
• Potentially allelopathic
  
• Flammable and may increase fire risk where grown
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Forms pure stands within native range
  
• Hybridizes with other Abies species
  
• Produces wind-dispersed seeds
  
• Larger trees may be resistant to fire

Low Risk Traits:

• No reports of negative impacts where introduced or naturalized
  
• Unarmed (no spines, thorns or burrs)
  
• Palatable to grazing animals (although palatability may be low)
  
• Non-toxic
  
• Landscaping and ornamental value (Christmas Trees)
  
• Not reported to spread vegetatively
  
• Long time to reproductive maturity (40+ years)
  
• Will not form a persistent seed bank