Family: Pinaceae

Origin, Description & Uses
Pinus elliottii, commonly known as slash pine, is native to the southeastern United States and has been widely planted in tropical and subtropical regions for forestry, windbreaks, erosion control, and ornamental landscaping. This fast-growing evergreen conifer is recognized by its tall straight trunk, long glossy needles grouped in bundles, and large woody cones. Slash pine is valued for timber, pulpwood, resin production, and its ability to tolerate a range of soil conditions, including sandy and seasonally wet areas. In Hawaii, it has become naturalized on Kaua‘i, O‘ahu, and Moloka‘i.

Risks & Threats
Although slash pine has useful forestry and landscape applications, it is naturalized in Hawaii and possesses traits that are cause for concern. This species can spread beyond planted areas through abundant seed production and may establish dense stands that compete with native vegetation, alter soil conditions, and increase fire risk by contributing flammable needle litter and woody debris. Pine invasions can also change habitat structure and ecosystem processes in sensitive tropical environments. Ongoing evaluation is needed to better understand its long-term impacts in Hawaii, and caution is recommended when planting this species to help prevent further spread into natural areas.

High Risk Traits:

• Naturalized beyond native range (SE USA)
  
• Environmental weed in Australia
  
• Congeneric weeds exist (Pinus pinaster)
  
• Widely introduced & regenerates naturally across multiple continents
  
• Creates fire hazard via fuel accumulation
  
• Tolerates wide range of soils (sand, clay, acidic, infertile, seasonally wet)
  
• Produces viable seed with rapid germination
  
• Hybridizes naturally with several Pinus species
  
• Wind-dispersed seeds (up to 75 m)
  
• Intentionally spread by people for forestry

Low Risk Traits:

• Not allelopathic or parasitic
  
• Not toxic to animals or humans
  
• Shade intolerant
  
• Minimum generation time ~7 years
  
• Very low self-fertility (~2.5% viable)
  
• No persistent seed bank (>1 year)
  
• Not dispersed as contaminant or by birds