Family: Pinaceae

Origin, Description & Uses
Pinus pinaster, commonly known as cluster pine or maritime pine, is a large evergreen conifer native to western and central Mediterranean regions of southern Europe and North Africa. This fast-growing pine typically develops a tall, straight trunk with a broad, irregular crown and long paired needles. It is valued for timber, pulpwood, erosion control, dune stabilization, and resin production, and has also been planted as an ornamental and windbreak tree in suitable climates worldwide. Its tolerance of dry, sandy, and nutrient-poor soils has contributed to its widespread cultivation outside its native range. In Hawaiʻi, this species has become naturalized on Maui.

Risks & Threats
Although planted for forestry and landscaping purposes, Pinus pinaster possesses traits associated with invasive behavior and is considered a high-risk species in Hawaiʻi. It produces abundant wind-dispersed seeds, establishes readily in disturbed environments, and can spread into natural areas where it may compete with native vegetation and alter ecosystem processes. Dense stands of maritime pine can change soil chemistry, increase fire risk through the accumulation of flammable needles and litter, and reduce habitat quality for native plants and animals. Because this species is already naturalized in Hawaiʻi and could detrimentally impact tropical island ecosystems, planting is discouraged. When suitable, low-risk or native alternative tree species should be selected instead.

High Risk Traits:

• Broad climate suitability and Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Naturalized on Maui (Hawaiian Islands) and elsewhere
  
• Environmental weed in higher elevation of Hawaiian Islands and in South Africa
  
• Other Pinus species are invasive
  
• Pollen is a potential allergen
  
• Highly flammable; increases fire risk in natural ecosystems
  
• Tolerates many soil types
  
• Forms dense stands
  
• Reproduces by seed
  
• Self-compatible
  
• Seeds dispersed by wind, intentionally by people and possibly by animals
  
• Prolific seed production
  
• Seeds may form a persistent seed bank
  
• Produces serotinous cones. Seeds may remain viable on trees for several years

Low Risk Traits:

• Primarily a tree of temperate and Mediterranean climates; may limit invasiveness to higher elevation in the tropics
  
• Unarmed (no spines, thorns, or burrs)
  
• Palatable to grazing animals
  
• Does not tolerate shade
  
• Not reported to spread vegetatively
  
• Reaches maturity in 6+ years
  
• Mechanical control is effective (will not resprout if cut below lowest branches)
  
• Does not tolerate fire
  
• Natural enemies present in Hawaiian Islands (Eurasian pine adelgid ("aphid") (Pineus pini)