Family: Pinaceae

Origin, Description & Uses:
Picea engelmannii, commonly known as Engelmann spruce, is a tall evergreen conifer native to western Canada, the western and west-central United States, and northeastern Mexico. It is typically found in cool mountain forests at higher elevations, where it can form extensive stands with fir and pine species. This spruce is recognized for its narrow, conical shape, bluish-green needles, and small hanging cones. Engelmann spruce is widely valued as a timber tree for lumber, plywood, and specialty wood products, including musical instruments due to its light, resonant wood. It is also planted as an ornamental tree in colder climates and is appreciated for its attractive form and evergreen foliage.

Risks & Threats:
Engelmann spruce is considered a low risk species for Hawai‘i and is not known to naturalize in the islands. Because it is adapted to cold, high-elevation continental climates, it is generally poorly suited to tropical island environments and has limited potential to spread aggressively in Hawai‘i. There is little evidence that this species poses significant ecological threats such as displacing native vegetation or altering natural ecosystems. As with many non-native plants, care should still be taken to avoid planting near sensitive natural areas, but overall Engelmann spruce is regarded as a relatively low concern species for tropical Pacific ecosystems.

High Risk Traits:

• History of repeated introductions outside native range (e.g., Hawaii, Europe, New Zealand)
  
• Congeneric weeds exist (e.g., Picea sitchensis)
  
• Creates a fire hazard in natural ecosystems
  
• Shade tolerant
  
• Forms dense thickets / pure stands
  
• Produces viable seed
  
• Hybridizes naturally
  
• Self-compatible (self-fertilization possible)
  
• Reproduces by vegetative fragmentation (layering)
  
• Seeds adapted for wind dispersal
  
• Dispersed intentionally by people

Low Risk Traits:

• Not naturalized beyond native range (no evidence from Hawaii, Europe, British Isles)
  
• Not a garden, agricultural, or environmental weed
  
• No spines, thorns, or burrs
  
• Not toxic to animals or humans (no allergy reported)
  
• Unpalatable to grazing animals (low forage value)
  
• Requires cold, humid, high-elevation climate; not suited to tropical/subtropical regions
  
• Narrow soil tolerance (prefers deep, well-drained loamy soils)
  
• No substantial reproductive failure in native habitat
  
• Propagules not likely dispersed unintentionally or as produce contaminant
  
• No evidence of seed survival through animal gut
  
• No prolific seed production (<1000/m²)
  
• No persistent seed bank (>1 year) – seeds lose viability quickly
  
• Does not tolerate fire (easily killed)