Family: Cupressaceae

Origin, Description & Uses:
Sequoia sempervirens, commonly known as California redwood, is native to the foggy coastal regions of southwestern Oregon and western California. It is the tallest tree species in the world, capable of reaching heights exceeding 300 feet (90 meters), and is renowned for its massive trunk, reddish-brown bark, and remarkable longevity. California redwoods are prized as ornamental and specimen trees in parks, large landscapes, and arboreta, where they provide dramatic visual appeal and shade. Their wood is also highly valued for its durability, resistance to decay, and use in construction, outdoor structures, and specialty wood products.

Risks & Threats:
California redwood is considered a low-risk species for Hawaiʻi. It is adapted to cool, moist climates with frequent fog and generally does not thrive or spread aggressively in the tropical environments found across most of the Hawaiian Islands. The species is not known to be invasive in Hawaiʻi and has not demonstrated a tendency to naturalize or displace native vegetation. While any introduced plant should be monitored when cultivated outside its native range, California redwood poses little risk to Hawaii’s natural ecosystems and can be a suitable choice for appropriate landscape settings where its large mature size can be accommodated.

High Risk Traits:

• Widely introduced globally for timber and ornament
  
• Resprouts vigorously after fire or logging
  
• Produces viable seed starting at 5–15 years
  
• Seeds wind-dispersed and intentionally spread by people
  
• Wood dust causes allergic reactions (asthma, dermatitis)

Low Risk Traits:

• Not naturalized beyond a single site in New Zealand
  
• No evidence of weediness or invasiveness
  
• Suited only to temperate, coastal climates
  
• No allelopathy, toxicity to animals, or major pests
  
• Does not form thickets or spread vegetatively
  
• Seeds disperse only short distances and do not persist in soil